Optimizing Feeding Behavior and Feed Intake Rick Grant W.H. Miner Agricultural Research Institute Chazy, NY 12921 Introduction Adequate consumption of feed ensures survival, productivity, and profitability of dairy cattle, consequently an understanding of feed bunk management and facility components affecting feeding behavior is critical. Feeding is the predominant behavior of ruminants as shown by the fact that feeding activity has priority over rumination whenever the causal factors of the two activities conflict (Metz, 1975). Well-designed cattle management systems accommodate natural feeding behavior to improve animal comfort and well-being. For example, accessibility of feed during times of the day when cows want to eat, e.g. when leaving the milking parlor, promotes greater feeding activity in dairy cattle (Menzi and Chase, 1994). Likewise, proper animal grouping strategies within dairy herds will reduce competition for feed at the bunk or manger and improve feed intake. For any dairy enterprise, the feeding and housing facilities must promote intense, aggressive feeding behavior by the herd. Researchers at Michigan State University (Dado and Allen, 1994) observed that higher producing, older cows consumed more feed, ate larger meals more quickly, ruminated longer and more efficiently, and drank more water than lower producing, younger cows. To achieve this intensity of feeding behavior, the cow’s environment must be such that it ensures cow comfort, non-disrupted feeding activity, and natural social behavior. Aggressive feeding behavior results in greater dry matter intake, optimal milk production and reproduction, higher feed efficiency, and improved herd health (Grant and Albright, 1997). Feeding Behavior and Dry Matter Intake: The Big Picture The essential components of physiological control of feed intake have been reviewed (NRC, 1987; 2001). Whether intake is controlled primarily by ruminoreticular fill or some metabolic feedback mechanism (realistically it will be a combination), psychogenic factors, as discussed by Mertens (1994), certainly will modulate dry matter intake. Psychogenic regulation of feed intake involves the cow’s behavioral responses to inhibitory and stimulatory factors in the feed or feeding environment separate from the diet’s energy or fill value. Palatability, social interactions, and learning behavior are integral components of psychogenic modulation of feed intake. Figure 1 depicts the concept of control and modulation of dry matter intake in dairy cattle. Factors that modulate intake can be optimized by the dairy producer to promote intense feeding behavior and maximum dry matter intake, particularly during the periparturient period. In contrast, ruminoreticular fill and chemostatic mechanisms are a function of body size, production level, age, and physiological state of the cow and cannot be influenced readily by the dairy producer.

Figure 1. Control and modulation of dry matter intake in dairy cattle (The Big Picture). Social Dominance and Competition Cattle Management Feeding Strategy Environment Feeding System Herd Health MODULATION Chemostatic Mechanism

Feeding Behavior Dry Matter Intake Number of meals Meal length CONTROL Eating rate Ruminoreticular Fill Chemostatic Mecha nism

Feeding Behavior and Dry Matter Intake Daily feed intake comprises the number of meals consumed daily, the length of each meal, and the rate of eating. By adjusting the number of daily meals and the average meal size (length x rate of eating), the cow can adjust daily dry matter intake. High-producing cows allowed continuous access to a total mixed ration eat 9 to 14 meals per day; lower producing cows consume 7 to 9 meals per day (Grant and Albright, 1995). Even though the definition of what constitutes a meal differs among researchers, evidently the eating patterns of high-producing, early lactation cows differ substantially from those of lower producing, later-lactation cows. In addition, cattle are crepuscular, or in other words, they are most active at sunrise and sunset (Albright, 1997). Periods of major feeding activity usually occur during these times. Recent research with cows in free-stall housing confirmed that feed alley attendance was consistently higher during the day and early evening compared with late night and very early morning hours (DeVries et al., 2003). Understanding how to optimize the feeding behavior of the dairy cow, particularly the transition cow during the periparturient period, within a given feeding environment is crucial to making profitable dairy management recommendations. Important differences exist for cows housed in free-stall versus tie-stall barns. For example, cows housed and fed in tie stalls have more eating bouts than cows in free stalls fed at a manger that provided 0.76 cm per cow, although total eating times were similar (Colenbrander et al., 1991). Albright (1993) extensively reviewed feeding behavior of dairy cows for competitive and noncompetitive situations. The most intensive investigation of feeding behavior since is that of Dado and Allen (1993; 1994). In their primary study, 12 Holstein cows (6 primiparous) averaging 63 days in milk were offered a common diet and monitored for 21-day periods

with an automated data acquisition system to continuously measure feed and water intake and associated chewing behavior. In the noncompetitive environment of this study, milk production was correlated positively with dry matter and water consumption within and across parities. For multiparous cows, milk production was related positively to meal size (r = 0.78) and length of eating bouts (r = 0.75), but was unrelated to meal number and eating rate. A similar observation was made for nonlactating dairy cows by Metz (1975). For primiparous cows, milk production was related positively to meal number (r = 0.55) and eating rate (r = 0.87) but unrelated to meal size. High-producing cows achieved greater dry matter intake by increasing meal size, with less time spent eating and ruminating per unit of intake. Results of Dado and Allen (1994) suggested that different mechanisms may be controlling individual meals and total daily dry matter intake between cows of different parity, ruminal capacity, or body weight. Behavioral Characteristics of Highly Effective Cows Natural behavioral characteristics of the high-producing cow include aggressive eating habits and consuming large amounts of high-quality forage and feed (Grant and Albright, 1995). As an example, the dry matter intake attained by Beecher Arlinda Ellen varied from 4.4 to 6.7% of body weight during the lactation in which she produced 25,248 kg of milk. In research reviewed by Grant and Albright (1995; 2000), the following ingestive characteristics of highly effective and productive dairy cows were summarized:

• Greater feed intake. The highest milk producing cows (multiparous) consumed 25

kg/d of dry matter, but the lowest producing cows (primiparous) consumed only 19.1 kg/d. Average milk production for the highest and lowest producing cows was 38.0 and 29.0 kg/d, respectively.

• Consumed larger meals. The most effective cows ate larger meals rather than more meals per day. The average high-producing cow ate 2.3 kg of dry matter per meal, while the low producing cows ate only 1.7 kg.

• Faster eating rate. Highest producing cows ate faster than low producers. Highest producing cows consumed 5 kg of dry matter during each hour of eating, but the low cows ate only 3.8 kg/h.

• Ruminated longer. Highest producing cows ruminated 23 min/d longer than low producing cows. The highest producing cows had fewer rumination bouts, but they lasted longer than the low producers.

• Ruminated more feed. Highest producing cows ruminated more feed per hour of rumination time. These cows ruminated 3.2 kg of dry matter per hour of rumination versus 2.7 kg of dry matter for the lowest producing cows. The high producing cows did not ruminate faster (chew their cud faster); they were more efficient because they processed more total feed per unit of time.

• Consumed more water. Highest producing cows drank 26 L more water per day than low producing cows. High producing cows not only drank more often (15 versus 13 times/d), but they also had a larger drink size of 7.2 L versus 5.4 L per drinking bout.

• Greater behavioral intensity. When the highest producing cows were eating, drinking, or ruminating, they performed this activity with more intensity than other cows. These highly productive cows are capable of getting a greater amount of

ingestive and ruminative work done in a shorter period of time than lower producing cows.

We need to keep in mind that these data were gathered for cows in tie-stalls with no competition for resources. But, they are the best data we have right now, and provide a good place to start for targets for aggressive feeding, drinking, and ruminative behavior. The bottom line is that the most highly effective cows accomplish a greater amount of ingestive and ruminative work in a shorter period of time. This intensity of behavior should be the goal for every dairy producer; therefore, our objective must be to assemble management practices that encourage aggressive feeding behavior, effective rumination, and greater water consumption.

Table 1. Summary statistics for milk production and feeding behavior of primiparous and multiparous lactating Holstein cowsa

Primiparous Multiparous All cows Variable

Mean CV Mean CV Mean CV (%) (%) (%) Milk production, kg/d b 28.7 15.5 37.5 13.7 33.1 19.7 DMI, kg/d b 20.0 13.6 24.8 11.3 22.8 16.1 NDF intake, kg/d b 6.2 13.8 7.6 11.4 7.0 16.1 Meal size, kg DM 1.8 17.0 2.5 29.8 2.2 30.6 Eating bouts/day 11.3 17.3 10.8 25.4 11.0 22.1 Eating bout length, min 25.9 22.2 31.1 33.4 28.8 31.3 Eating time Min/d 284 16.5 314 16.8 301 17.3 Min/kg of NDF 51.1 22.4 44.3 14.4 47.2 20.1 Eating chew/day 18,276 22.8 19,25

6 16.9 18,832 19.6

Eating chew rate,chews/min 62.7 7.4 60.8 8.7 61.6 8.3 Ruminating bouts/day 15.4 17.5 12.9 13.3 14.0 17.8 Ruminating bout length,min b 29.7 15.9 36.0 19.9 33.3 20.9 Ruminating time Min/d 453 18.3 460 14.8 457 16.3 Min/kg of NDF 74.1 20.9 60.9 19.0 66.6 22.3 Ruminating chews/day 29,645 21.5 28,94

6 17.6 29,248 19.3

Ruminating chew rate, /min 64.4 10.7 61.8 7.2 62.9 9.1 Total chewing time Min/d 738 13.9 774 11.4 758 12.6 Min/kg of NDF b 120.7 15.6 102.0 13.8 110.1 17.0 Total chews/day 47,921 19.1 48,20

1 14.3 48,080 16.4

Water intake, L/d b 63.2 19.5 89.5 15.0 77.6 23.8 Drinking bout size, L 5.4 33.2 7.2 43.8 6.4 43.1 Drinking bouts/day 13.0 35.9 14.9 41.9 14.0 40.2 Drinking time, min/d 17.7 37.4 19.1 20.0 18.5 28.7 Drinking rate, L/min 3.9 31.0 4.6 11.0 4.3 22.4

aTable from Dado and Allen (1994). bMeans differ between parities ( P < 0.05).

Several studies have found that primiparous cows (first-calf heifers) eat more slowly than older cows (Campling and Morgan, 1981; Beauchemin and Rode, 1994). The greater time needed for younger cows to masticate feed ought to be an important consideration for feeding strategies designed to promote dry matter intake. Greater feed availability and reduced

competition at the feed bunk should increase dry matter intake by primiparous cows, especially during the transition period. In fact, several studies have demonstrated 10 to 15% improvements in dry matter intake and milk yield when primiparous cows are grouped separately from older cows.

Targets for Dry Matter Intake

The two goals for dry matter intake in dairy cattle are 1) to maximize intake of a well-formulated ration, and 2) to reach maximum dry matter intake as soon as possible after parturition. The new National Research Council publication on Dairy Cattle Nutrient Requirements (Dairy NRC, 2001) states that peak milk yield occurs by 4 to 8 weeks postpartum, but peak dry matter intake doesn’t occur until about 10 weeks postpartum. This lag between peak milk and peak feed intake is the major nutritional challenge of feeding the early lactation cow. Any management routine that improves intake earlier in lactation will reduce the severity of negative energy balance and result in healthier and more productive cows. Rate of increase in dry matter intake during early lactation is a primary determinant of energy intake and energy balance (Grant and Albright, 1995). Dry matter intake increases by approximately 1.5 to 2.5 kg/wk during the first 3 weeks of lactation (Kertz et al., 1991). Differences in feed intake between multi- and primiparous cows partly explain this range in the rate of dry matter intake increase postpartum. Kertz et al. (1991) compiled data from 469 cows and observed that older cows had a greater rate of increase in dry matter intake for the first 5 weeks of lactation than first-lactation cows. This difference alone suggests that primiparous cows should be grouped and managed differently from older cows. The target rate of increase in dry matter intake for primiparous cows during the first 3 wk of lactation is 1.4 to 1.8 kg/wk. For multiparous cows, the target rate of increase is 2.3 to 2.7 kg/wk. Table 2 presents the target dry matter intake for primi- and multiparous cows for the first 5 wk of lactation. Table 2. Dry matter intake (kg/d) for 545-kg primiparous and 636-kg multiparous cows.

Week Primiparous Multiparous 1 14.1 16.6 2 15.9 19.3 3 17.3 21.1 4 18.2 22.3 5 18.9 23.9

The Dairy NRC (2001) uses the following equation to predict dry matter intake: DMI (kg/d) = (0.372 x FCM + 0.0968 x BW0.75) x (1 – e(-0.192 x (WOL + 3.67))) where FCM = 4% fat-corrected milk (kg/d), BW = bodyweight (kg), and WOL = week of lactation. The term with WOL adjusts for depressed feed intake that occurs in early lactation. There are no adjustments made for parity (age of animal) or heat stress with this equation. It is assumed that using the correct body weight and milk production will automatically adjust the equation for differences in intake due to age or environmental conditions.

Feeding Area Design and Feeding Behavior The design and layout of the feeding area play an important role in facilitating the naturally aggressive feeding behavior that we just described and maximum dry matter intake. Major considerations include:

• Bunk or manger space available per cow • Manger surface, height, and slope • Configuration of the feed barrier and headlocks • Accessibility and availability of feed to the cow • Alley width and flooring behind feed manger

These components of the feeding facility must be assembled in a manner that allows the cow unhindered access to feed, encourages aggressive, intense feeding behavior, and accommodates normal social interactions within a group of cows. Alley Width and Living Space Alley width and feeding behavior. On-farm observations suggest that the amount of space available to the dairy cow between the feed manger and the first row of stalls is crucial to achieving maximum feed intake and cow comfort. In field observations of ten dairy herds in Nebraska during the summer of 1997 (Grant and Albright, 1997), in most cases farms with the highest dry matter intake and productivity had alleys of sufficient width so that two cows could walk comfortably in opposite directions behind the row of cows standing and eating at the feed line. In addition, cows were able to exit a stall without interference from, or interfering with, cows that were eating. With insufficient space, either from poor barn design or overcrowding, normal movement of cows in the alley behind the feed manger disrupts eating activity, precipitates fights, and interferes with intense, focused feeding activity. Many free stall barns designed today in the USA provide floor space of approximately 3.7 to 5.1 m2 per cow, excluding free stall and drinking areas. The alley between the feeding line and the first row of free stalls should be at least 4.3 m wide to allow comfortable cow movement and avoid interference with feeding activity. Another major consideration is comfort of the first row of stalls; if cows stand half-in and half-out of the stalls, they will obviously reduce the usable alley space behind the feed manger. Cattle gridlock. With insufficient alley space, overcrowding, or uncomfortable stalls, cows can experience what we’ve termed “grid lock”. Essentially, the cow finds herself in a situation where movement is extremely difficult, and thus her access to feed, water, stalls and other resources is limited. We have observed this situation with two on-farm studies in Nebraska during the summer of 2000 (Grant, unpublished data); both farms had free stall barns with 3.1-m alleys between the feed line and the first row of free stalls. The degree of overcrowding of stalls ranged from 17 to 22%, and there was 0.17 to 0.42 linear meters of bunk space per cow. Both herds experienced low feed intake and milk production. During a 2-h time period following the morning delivery of feed, we observed that cows were unable to move about freely in the barn to reach waterers, access the fresh feed, or lie down in a stall. Hence, the term grid lock. It is probable that this problem increases in severity as facilities become overcrowded, particularly older facilities that were designed originally with inadequate alley widths.

Figure 2 shows data from a commercial dairy of the percentage of cows standing, or idling, in the alleys and crossovers. This group of cows was well-managed, with no overcrowding of feed or stalls, and illustrates that very few cows should be in the alleys rather than resting or eating. The bottom line is that cows should be in the alleys only when “in transit.” Figure 2. Data from a commercial dairy showing percentage of cows in

crossovers and alleys. Although number of cows varies throughout the day depending on management routines occurring, the point here is that few cows should be standing in alleys for extended periods of time. The average % in alleys for this farm was 5% of cows.

Feed Bunk or Manger Design Elevation of feed bunk. Many dairies use fenceline feeding systems in which cows eat with their heads in a natural grazing position. Evidence exists that cows eating with their heads in a downward position secrete 17% more saliva than cows eating with their heads held horizontally, which could result in better ruminal function (Albright, 1993). This observation makes sense given that the dairy cow is by nature a grazing animal. Cows exhibit more rooting behavior in shallow, elevated bunks or troughs. Albright (1993) observed lactating dairy cows once weekly for feed tossing behavior when they were fed a total mixed ration. Approximately 10% of the cows observed participated in this behavior. The amount of feed wasted was 0 to 5% each week. Feed tossing was especially prevalent in summer during periods of heavy fly concentrations, but it occurred in winter as well. When given the choice of eating from an elevated bunk with the floor either 28 or 76 cm from ground level, or from the same trough at ground level, cows chose the lower level. Also, the group fed at ground level exhibited no feed tossing behavior. It appears that the optimally constructed feed bunk or manger is at a height that allows cows to consume feed in a natural grazing position. Although rare, feed tossing behavior can still occur with cows in self-locking stanchions with their heads in the head down position. Cows will also consume more feed when the ration is offered in a fenceline feed manger versus an elevated feed bunk that the animals can move around completely (Albright, 1993). Manger slope and surface. Data summarized by Grant and Albright (2000) indicated that the floor of the feed manger should be level or slope no more than 1 to 2% along the length of

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the feed bunk. When mangers have slopes of >3 to 5%, cows shift and move in the direction of the slope. This movement is continual and interferes with feeding activity. Concrete mangers that have been renovated with epoxy finishes, wood, or tile aid feed consumption (Albright and Grant, 2000). Over time, lower pH silages can etch and pit concrete, which exposes the cow’s tongue and mouth to rough and sharp edges. Also, on-farm observations suggest that providing a smooth finish to the front side of the stem wall facing the feed will reduce the chance of feed lodging in small crevices, creating odors, and reducing feed consumption. A smooth finish on all surfaces that come into contact with feed reduces abrasion and also odors thereby stimulating feed intake. Bunk Space and Competition for Feed Mature cows. A major consideration when managing dairy cattle is the proper amount of feeding space allowed per animal to ensure that feeding behavior is not affected adversely. When lactating cows are fed at a bunk or manger, the critical length of bunk space per cow, below which excessive competition occurs, varies with group size and amount and availability of feed. Several early reports established that little change occurred in feeding behavior when bunk space was reduced from 0.61 to 0. 31 m per cow (reviewed by Albright, 1993). A reduction in bunk space from 0.49 to 0.09 m per cow to increase competition strengthened the correlation between dry matter intake and the dominance value of the individual cow (cited in Dairy NRC, 2001). Albright (1993) postulated that a gradual reduction in bunk or manger space for an established group of cows may be better tolerated than adaptation of a new group to limited manger space. Table 3 summarizes the relationship between bunk space and feeding behavior. Table 3. Bunk space and feeding behavior of lactating dairy cows.1

Bunk space (m) Effect on dry matter intake (DMI) <0.20 Reduced eating time and DMI 0.20 to 0.51 Increased competition; variable

effect on DMI >0.51 to 0.61 No measurable effect on DMI 1Data summarized from Albright (1993), Friend and Po lan (1974), Friend et al. (1977), Manson and Appleby (1990), and Menzi an d Chase (1994).

Although current recommendations for linear feed bunk space are 0.61 m per cow, research results and on-farm observations of high producing herds with large group sizes indicate that 0.21 m per cow is near the critical bunk space. One should consider, however, the difference between minimum bunk space that can be tolerated in existing facilities with excellent management and desired bunk space in newly designed facilities. Barns tend to become overcrowded with time, and improperly designing a barn with regard to bunk space may not be advisable. The actual optimal bunk space will be a function of feed availability throughout 24 hours, relative to when cows want to eat, and the degree of crowding and competition placed on the cows by grouping strategy. Competition for feed and feed intake. When a competitive situation exists at the feed bunk, dominant cows typically spend more total time eating than cows of lower social rank, resulting in greater feed intake. Recently, Swedish researchers (Olofsson, 1999) evaluated the

effect of increasing competition from one to four cows per total mixed ration feeding station. As competition per feeder increased, cows exhibited shorter average eating times and accelerated eating rates. Similarly, visits to the feeding station increased in direct proportion to greater aggression during feeding. However, feed intake was unchanged. In contrast, when cows were fed limited amounts of feed, dominant cows consumed 14% more feed than submissive cows. This divergence increased to 23% as competition increased from one to four cows per feeding station. Under conditions of limited feed availability, competition escalates and feed intake of submissive cows suffers. In addition, when competition increased from one to four cows per feeding station, a higher proportion of the feed consumption occurred during the night (1800 to 0600 h). The cows also spent a smaller proportion of time standing during the night with greater competition for feed. As level of competition increased, cows of low social rank tended to adjust behaviors to a greater extent than did the more dominant cows. Instead of eating, the subordinate cows were observed standing and lying more often around milking time, when eating would have been preferred. The early research on feeding space and behavior evaluated small groups of cows (50 to 60 or fewer) at low to moderate levels of milk production. Application of these results to modern dairies requires observations of larger groups of cows at higher levels of milk production and feed intake. The traditional rule of thumb of 0.65 m of bunk space per cow is the minimal amount of space required for all cows to eat at one time. However, the advent of total mixed rations and proper feed bunk management raises questions regarding the adequacy of this relationship. Menzi and Chase (1994) conducted a field study using two commercial dairy herds in New York state to examine feeding behavior and bunk use for high-producing herds. Both herds were producing in excess of 10,400 kg of milk yearly, were milked three times daily, used 6-row drive-through free stall barns, and were fed a total mixed ration two or three times daily, with 88 to 90 cows in each group. The groups of cows observed for each farm had the highest feed intake and milk production per cow, and therefore should have exerted the greatest feeding pressure on the bunks. Cows in these groups averaged 40 kg of milk per day, with a dry matter intake of at least 23 kg/d. A video camera was mounted above and slightly behind the feeding area to provide the best view of feeding activity. Each herd was videotaped for a 24-h period during August when high temperatures were 80.6oF and low temperatures were near 60.8oF. Using the videotape, a feed bunk usage score was developed where 0 represented no animals at the feed bunk and 10 indicated that the bunk space was entirely occupied with no additional room for animals to eat. In these herds, cows increased bunk usage after feeding, when feed was pushed up, or when returning from the milking parlor. Feed bunk management that provided fresh feed throughout 24 hours, within reach of the cows, promoted numerous, smaller meals throughout the day. We have noticed similar feeding behavior in herds that we observed in Nebraska and New York state. Transition cows. A recent on-farm study (Buelow, 1999, personal communication) showed that close-up dry cows (within 2 weeks of parturition) had the greatest feed intake when the

occupancy of headlocks was 80 to 90%. A decline in feed intake was noticeable even at 100% occupancy indicating that these transition cows are extremely sensitive to competition for feed. Dairy Heifers. Much less is known about the need for feeding space and the feeding behavior of dairy heifers at various ages and body sizes. Maintaining adequate growth of a group of heifers, and also of the individual heifers within a group, depends on the housing and feeding systems, and their impact on cow comfort and behavior. To achieve growth rates that allow parturition at 24 months of age requires that bunk space should not limit feed intake. Previous recommendations were based on heifers with much slower rates of gain than currently desired. Recent research (Longenbach et al., 1999) evaluated the amount of feed bunk space required by dairy heifers at various ages grown at uniformly rapid rates of gain to achieve adequate body size and weight for parturition by 24 months of age. Three groups of heifers were defined by an average age of 4, 11.5, and 17 months. Bunk space of 0.15, 0.31, and 0.47 m per heifer was evaluated. Heifers were fed a total mixed ration at restricted intakes to achieve an average daily gain of either 0.82 kg/d (4 and 11.5 months of age) or 0.91 kg/d (17 months of age). The authors concluded that, based on the observed feeding and growth responses of each group, the following feed bunk space recommendations are optimal for rapidly growing Holstein heifers fed a total mixed ration in either a free stall or loose housing system: 0.15 m for 4 to 8 months, 0.31 m for 11.5 to 15.5 months, and 0.47 m for 17 to 21 months of age. Feed Barrier Design: Restraint with Headlocks Self-locking stanchions (headlocks) are commonly used in commercial dairies to restrain cattle for various management tasks such as 1) artificial insemination, 2) pregnancy checking, 3) monitoring herd health, and 4) top dressing a supplement. This system of restraining cattle in the feeding area can be abused, and thus compromise cow comfort when cows are allowed to remain in the headlocks beyond the period of time actually necessary for the management routine. Effect of head locks on behavior and performance. To investigate the effect of restraint using self-locking stanchions, 64 Holstein cows from peak to end of lactation were restrained in these stanchions for approximately 4 h/d for four periods in a modified switchback design (Bolinger et al., 1997). Milk production, somatic cell count, and total daily feed intake were unaffected by the restraint. Behaviorally, cows that were locked up spent significantly more time lying down after release from the headlocks. For cows that were locked in stanchions, eating frequency over 24 h was significantly reduced, but dry matter intake was not affected (i.e. they were slug feeding). Total rumination frequency over 24 h was not affected, but restrained cows ruminated less during the following day (which could exacerbate the effect of slug feeding). Grooming was significantly increased during all times that cows were not locked up, and was considered to be a behavioral need. Grooming was also one of the first behaviors performed following release. Acts of aggression were elevated during all periods following restraint. Although the proper use of self-locking stanchions for restraint does not

seem to substantially affect the overall well-being of the cow, there appears to be a real potential to impact feeding and ruminating behavior adversely. Behavior while locked up. Figure 3 illustrates cow behavior over time when locked into headlocks. Within ~1 hour, cows will have finished eating, and after ~45 minutes to one hour, cows will gradually begin to ruminate. It appears that, for the herds we have evaluated, the percentage of cows ruminating while locked in stanchions levels off at approximately 40% of cows in the headlocks. A question to ponder: what effect does extended time in headlocks have on the cow’s daily time budget? Based on this research, it may be that more than one hour will interfere with the cow’s time budget.

Figure 3. Eating and ruminating behavior over time when cows are locked in stanchions at the manger with fresh feed available (Matzke and Grant, 2003).

Headlocks versus Post and Rail Systems Several recent studies have examined the impact of headlocks versus post and rail feeding systems on feed intake and cow behavior. Batchelder (2000) evaluated the effect of head locks versus post and rail feeding with either 0 or 30% overcrowding. In this study, regardless of degree of overcrowding, there was a 1 kg/cow/day reduction in dry matter intake for cows using headlocks. This research was done in a 4-row barn and feed was pushed up 3 to 5 times between each milking. In contrast, Brouk et al. (2001) observed no effect of headlocks versus post and rail feeding systems on feed intake or milk production for primi- or multiparous cattle. Cattle in this study had been previously exposed to headlocks, and the effect of headlocks on naïve cattle remains unknown. In practice, it is a good idea to leave several feeding spaces open (as simply post and rail) at the ends of the feed manger

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when installing headlocks; this space then serves as an easier place for hesitant cows to feed and also provides an easy point for people to enter or exit the pen rapidly. Another major consideration with post and rail systems is that it necessitates that cows spend more time away from the pen for management routines, and so cows have less access time for resources such as feed, water, and stalls. Feed Barrier Design: Pressure Exerted During Feeding Feed barriers and mangers should provide free access to feed without risk of injury or discomfort. Feed mangers or barriers should also allow undisturbed feeding activity and minimize feed wastage. Additionally, cows can be restrained by some feed barriers such as self-locking stanchions as was just discussed. A relationship may exist between the layout of the feeding area, particularly feed barrier design, and the number of injuries for cattle. The barrier between the cows and their feed is often constructed in such a way that cows press hard against the barrier when attempting to reach their feed, thereby increasing the risk of injury or discomfort. Remember that cows have a natural aggressive feeding drive that will be frustrated if we force them to push hard against a feed barrier for extended periods of time to reach feed. A well-designed feeding system should result in cows needing to exert the lowest pressure against the feeding barrier while consuming feed. Pressures of <500 newtons have no effect on the cow, pressures of 500 (~112 pounds) to 1,000 (~225 pounds) newtons may cause harm, and pressures >1,000 newtons may cause acute damage (Hansen and Pallesen, 1998). These researchers evaluated the effect of the pressure exerted by dairy cows on self-locking feeders on feeding activity and cow comfort. Measurements taken during both day and night showed that >80% of the pressure occurred within the first hour after feeding. Peaks in pressure occurred when remaining feed in the manger was outside of the cow’s reach. Almost no pressures >500 newtons were recorded during the first minutes of a meal, as the cow ate the feed within its reach. Pressure against the feed barrier gradually increased as the cow tried to consume the feed at the outer limits of its reach. Importantly, cows gave up trying to reach feed after about 14 minutes, and left the feed manger. This observation reinforces the importance of pushing up feed frequently within the reach of the cow. It also points out the importance of when feed is pushed up. If cows are forced to push against a feed barrier for 15 minutes or more, the research suggests that they will then lie down, and will not return to the manger even if feed is subsequently pushed up. Oftentimes, feed is pushed up too late, even if it is 4 to 6 times daily, and consequently dry matter intake suffers. When accumulated pressure distribution was analyzed, the pressure on the feed barrier was >500 newtons for about 76 seconds, which could be harmful in the long term. A pressure >1000 newtons lasted for 43 seconds, which can cause acute tissue trauma. The highest pressure was recorded when cows reached straight for the feed. The effect was more pronounced as manger width increased, and feed could be pushed more easily beyond the reach of the cows. Hansen and Pallesen (1998) also evaluated the angle of the feed barrier, either vertical or with a 20o slope outward. The sloping feed barrier increased the cow’s reach and reduced

pressures exerted on the barrier by the cow. There was a 98.7% probability that pressure >500 newtons would be placed on the feed barrier when vertical versus tilted out at the 20o angle. This research indicated that cows willingly will place pressures >2,000 newtons against a feed barrier to reach as much feed as possible. At this amount of pressure, injury can easily occur. Therefore, feed should always be within easy reach of the cow (pushed up as needed). Mounting self-locking stanchions in a 20o angled position increased the cow’s reach by 0.14 m, with no increase in pressure, and enabled a wider feeding area in front of the cow (Hansen and Pallesen, 1998). Angling a feed barrier can result in a maximum reach that is up to 25% greater than that obtained with a vertical feed barrier. In the USA, when feed barriers are tilted outward, a common recommendation is 15o. A practical consideration is the width of the feeding alley, and how much this width is reduced by angling out the feed barriers; in some cases, the alley may become too narrow for feeding equipment to easily deliver feed. The bottom line is that feed accessibility needs to be assured, by pushing up feed and, if desired, by tilting the feed barrier. Feeding Strategies to Improve Ruminal Function and Feed Intake The feeding strategies used within any given feeding area design will also impact feeding behavior and feed intake. Although feed intake is controlled by a combination of ruminoreticular fill and chemostatic mechanisms, feeding strategy plays a major role in modulating feeding behavior. Feeding strategy refers to feeding frequency, feed availability and accessibility, degree of feed restriction, feeding sequence, and the feeding system. Feeding Frequency Gibson (1984) summarized 35 experiments on feeding frequency in lactating cows, noting that automated feeding systems offered the benefit of “little and often” feeding. In these studies, milk production increased only 2.7% and milk fat 7.3% when feeding frequency increased above once or twice daily. Intake increased sufficiently to explain some, but not all, instances of increased milk fat production. Of 11 experiments summarized by Gibson (1984) in which feed was offered for ad libitum intake, dry matter intake increased in response to feeding frequency in seven of the experiments. Importantly, most studies in this review involved multiparous cows, with no inference to heifers. Few reports stated the stage of lactation for experimental cows and so no inference can be drawn regarding the effect of feeding frequency on dry matter intake at various stages of lactation. Robinson (1989) pointed out the disparity between research results under carefully controlled feeding conditions and observations of commercial dairies regarding beneficial effects of increased feeding frequency. For a benefit to accrue from greater feeding frequency, existing fluctuations in diurnal patterns of ruminal metabolites and pH must negatively affect efficiency of microbial growth and fermentation. Benefits of increased feeding frequency, such as enhanced dry matter intake, involve attenuation of these fluctuations.

Dairy cattle fed a total mixed ration twice daily consumed 12.1 meals per day of 21 minutes each (Vasilatos and Wangsness, 1980). Approximately 25% of total eating time occurred within the first hour after feeding. If feed availability was restricted, more feed was consumed earlier in the feeding cycle. No definite effect of increased feeding frequency on dry matter intake or milk production existed when primiparous cows fed once daily consumed 10% of total feed intake within the first hour after feeding (Nocek and Braund, 1985). In this study, which began at 4 wk postpartum, diurnal patterns in ruminal metabolite concentrations were similar for cows fed from one to eight times daily. Table 4 summarizes the data from this study. Similarly, Robinson and McQueen (1994) found that a protein supplement fed either two or five times daily to early lactation dairy cows had no effect on dry matter intake because cows supplemented with five meals daily tended to consume the basal diet more rapidly after both the morning and afternoon feedings, which resulted in similar diurnal patterns of ruminal metabolites. As Robinson (1989) correctly noted, “because cows are offered feed more frequently, it does not necessarily follow that they will consume feed more frequently. Thus, diurnal patterns in ruminal metabolite concentrations occurring when cows are offered feed less frequently are not necessarily correctable by offering feed more frequently.” Another question is, what is the effect of once versus twice daily feeding, compared with two or more than two daily feedings? In practice, feeding more than twice daily is often not practical, especially when cows are fed in multiple groups.

Table 4. Effect of total mixed ration feeding frequency on intake, production, and ruminal function.1 Item 1x/day 2x/day 3x/day 4x/day DMI, kg/d 17.9 17.8 17.8 18.6 DMI (0600 to 1800), % of daily 67.4 64.6 61.3 62.2 Water intake, L/d 67.9 71.7 70.9 76.6 Milk yield, kg/d 27.5 27.5 28.4 28.4 Milk fat, % 3.85 3.73 3.68 3.80 Milk protein, % 3.25 3.35 3.33 3.35 4% FCM, kg/d 27.6 26.0 27.0 28.1 FCM/DMI, kg/kg 1.54 1.46 1.51 1.51 Ruminal pH 6.23 6.11 6.09 6.12 1 Summarized from Nocek and Braund (1985).

In commercial dairy herds, more total feed may be consumed during the first 2 to 6 hours after feeding than in research studies (Robinson, 1989). Potential reasons include insufficient bunk space for all cows to eat simultaneously, which increases consumption rate (i.e. slug feeding); reduces daily eating time; and lengthens periods of empty feed bunks at the end of a feeding cycle. Failure to feed cows for ad libitum intake (>5% refusal) will reduce dry matter intake similarly to insufficient bunk space. Heaney (1970) concluded from a review of voluntary intake trials that maximum intake could be measured with confidence when feed refusals were between 5 and 15%. However, a practical consideration on-farm would be subsequent use of refused feed for large numbers of cattle. Dairy producers may feed for only 2 to 3% feed refusal to minimize this problem. But, it is generally poor practice to feed to an “empty bunk” on dairy farms. Feedlot cattle fed to a clean bunk had reduced frequency of meals (4.5 vs. 8.2 meals/day) and greater average meal size (3.5 vs. 1.6 kg/meal) than cattle fed for ad libitum consumption (Milton, 1998). Milton (1998) also reported that deviations of 2 to 4 hours from a normal feeding schedule greatly increased the risk of acidosis in feedlot cattle. Dietary fermentability (feed bunk stability) and management of the feeding process (bunk cleaning, adequate bunk space, ad libitum access to feed) may influence productive benefits of feeding frequency (Table 4). Feeding a total mixed ration with greater frequency promotes a greater response when dietary fermentability is medium to high and feeing management is poor. Improved dry matter intake associated with greater feeding frequency will likely be more important in eliciting a productive response than improvements in ruminal fermentative efficiency.

Table 4. Projected benefits of increased feeding frequency of total mixed rations. Stage of lactation and diet fermentability Feeding management Relati ve response 1

Early (0-12 wk) High Good + + + High Poor + + + + + Medium Good + + Medium Poor + + + + Low Good + Low Poor + + Mid (13-24 wk) High Good + + High Poor + + + Medium Good + Medium Poor + + Low Good Low Poor + Late (25-44 wk) High Good High Poor + Medium Good Medium Poor Low Good Low Poor 1 Small (+) to large (+ + + + +) effect of feeding f requency on dry matter intake and performance of dairy cattle. Feed Accessibility and Availability

Albright (1993) asserted that accessibility of feed may be more important that the actual amount of nutrients provided. Feed intake and milk production may improve when cows are allowed access to feed when they want to eat, such as when leaving the milking parlor. A primary goal of the feeding program should be to ensure ad libitum access to feed, which allows for a greater margin of error in feeding management. Feed accessibility really has two components: 1) whether cows can reach the feed in the manger, and 2) how feed is distributed along the length of the manger. The first point refers to how often feed is pushed up and whether or not the feed barrier is angled, and the second point refers to how uniformly the feed is distributed in a manger. This point is especially important in larger facilities where cows may not routinely use the complete length of the feed line. Removal of feed access for 4.5 h/d reduced dry matter intake by 1.2 kg/d in a study by Goings and Braund (1975). However, cows were not adapted to reduced time of feed availability prior to behavioral observations. Erdman et al. (1989) noted that on some commercial dairies, feed access may be restricted to 12 h/d or less due to excessive time spent in milking and holding pens. These researchers used 32 cows averaging 132 days in milk to test effect of feed access time (8, 12, 16, or 20 h/d) on dry matter intake and milk production. Increasing access to a 40 or 60% corn silage total mixed ration, from 8 to 20 h/d, increased dry matter intake from 23.5 to 24.7 kg/d, but had no effect on intake as a

percentage of body weight. Eating time was not affected significantly by feed access time, although cows with 8 h of access time tended to spend less time eating. Table 5. Schedule of management activities for cows in a trial to examine effect of varying times of feed access on performance.1 Management activity 8 h/d 12 h/d 16 h/d 20 h/d Milking am 0230-0430 0230-0430 0230-0430 0230-043 0 Milking pm 1430-1630 1430-1630 1430-1630 1430-163 0 Exercise period 2 0700-0900 0900-1100 1100-1300 1130-1530 Feeding period 0230-0630 0230-0830 0230-1030 0230- 1130 Feeding period 1500-1900 1300-1900 1500-2300 1530- 0230 1 Table from Erdman et al. (1989). 2 Cows were turned out on a concrete lot for exercis e during this period.

Feed access time in excess of 20 h/d is a practical concern for dairy producers. When feed was offered for truly ad libitum consumption, and timing of feeding was consistent from day to day (Table 5), access to feed could be limited to 8 h/d with no adverse effects on dry matter intake and milk production. It is important to note that these were corn silage-based rations, and other forage sources could conceivably limit intake by gut fill when offered for only limited amounts of time each day. Feed bunks were never empty, and feeding periods consistently coincided with return of cows from milking (Table 5), a time shown by other researchers to be a period of peak feeding activity. Cows should not be without unspoiled feed for greater than 5 or 6 hours because rapid consumption of fresh feed could cause a depression in ruminal pH sufficient to inhibit microbial activity. Finally, the cows in this study averaged 26.0 kg/d of milk; whether higher producing cows, or cows in early lactation, would respond similarly has not been addressed. Feeding restriction can occur under a number of conditions (Grant and Albright, 1995). Aside from simply providing inadequate amounts of feed daily, other common, but less obvious, causes include: long holding area time; long time in exercise lot without feed; instable, highly fermentable silage; poor ventilation; slippery floors; inadequate or poorly maintained free stalls or comfort stalls; rough mangers; and overcrowding that results in inadequate stall or bunk space. Feeding Sequence Sequence of offering feeds may affect intake, ruminal function, and milk production, but a forage’s physical form and protein and starch degradabilities must be considered as well. Forage of medium to long chop length prolongs eating time, increases ruminal fiber load, and reduces intake of the subsequent meal, especially a concentrate fed separately from forage (as in a parlor). University of Arizona research showed that as alfalfa hay increased from 26 to 38% acid detergent fiber, cows consumed more meals per day, spent more time eating per day, and the time spent eating per meal increased. The amount of hay in the diet also affected eating activity with more time spent eating when hay was included in the diet at 50% versus 35%. Implications of this feeding behavior may be important in situations where bunk space is inadequate. When forage quality is low, more time will be required to consume feed. In overcrowded situations, competition for feed will restrict time cows have

to eat, thus reducing feed intake and milk production. Sorting is also a consideration with diets that contain long fibrous particles. Ruminal forage fill may reduce eating rate of the subsequent meal as well. Robinson (1989) speculated that when forage is fed first in the morning, the concentrate should contain relatively slowly degraded protein and rapidly fermented starch (barley, wheat, flaked corn) because the ruminal fiber mat traps grain particles and reduces ruminal escape. High moisture ear corn, a rapidly degraded starch source, has been fed before forage to improve dry matter intake slightly. Nocek (1992), using primiparous cows during weeks 4 to 19 of lactation, found that the feeding sequence of high-moisture ear corn + protein supplement (0700), ad libitum forage (alfalfa:corn silages, 1:1 dry basis) (1000), and high moisture ear corn + protein supplement (1800) promoted the highest dry matter intake. Cows fed this sequence ate 1 kg/d more dry matter, and slightly more dry matter as a percentage of body weight. Strategic feeding of protein and energy sources relative to forage can positively influence dry matter intake and milk production of dairy cattle. Stimulation of forage consumption is especially critical in feeding systems in which concentrates are fed before forage. If forage intake is limited (i.e. grain is overfed), ruminal acidosis may result with subsequent impairment of forage consumption. So, if several forages are available, the most palatable should be fed immediately after concentrates to stimulate feed intake. Less palatable forages can be offered later in the feeding cycle when appetite is greater. MacLeod et al. (1989) evaluated several concentrate feeding frequencies and sequences of hay and grain for diets based on hay crop silage consumed ad libitum. When hay was offered 2 h before or 0.5 h after concentrate, and was available 2 h before hay crop silage, dry matter intake and milk yield increased. The results suggest that inadequate effective fiber may limit dry matter intake, and if hay addition corrects the deficiency, intake will be stimulated. Sniffen and Robinson (1984) summarized work which showed that when roughage was fed 90 min after the concentrate rather than 90 min prior, there was a larger drop in ruminal pH and a reduction in cellulose digestion. Cows should not be provided with feeds containing high amounts of readily fermented proteins or carbohydrates first in the morning if cows have been without fresh feed for up to 6 h. In these cases, the rapid intake lasting for 15 to 30 min results in a high fermentation acid and ammonia load in the rumen. When forage is fed 1 to 2 h later, appetite will be depressed due to acidotic conditions in the rumen, and digestion of what has been consumed will be reduced due to low ruminal pH. Forage should be approximately 1 h prior to grain feeding in the morning. Feeding Strategies to Avoid Acidosis and Optimize Feed Intake A ration may be properly formulated on paper, but several management and housing factors can negatively influence the cow’s response including: 1) poor bunk management that allows sorting or slug feeding, 2) improper mixing and feed delivery, 3) overcrowding, and 4) anything that upsets the cow’s daily time budget.

Forage quality and feeding behavior. We know that a relationship exists between dietary NDF content and eating rate. Cows fed alfalfa-based rations containing from 19 to 25% ADF had increased time spent eating and greater meal lengths (Alhadrami and Huber, 1992). Clearly a feeding system that is overcrowded will have a greater potential negative impact as fiber content of the diet increases in terms of reducing feed intake. Feed sorting. Feed sorting can lead to ruminal acidosis, erratic feed intake, laminitis, low fat test, and increased risk of abomasal displacement. Shaver (2002) recently reviewed sorting behavior by dairy cows. In general, dairy cows tend to sort against larger particles (i.e. against coarse fiber), and this effect is most pronounced as alfalfa hay increases in the ration. Consumption of large particles (>0.75 inches or top screen of Penn State particle Separator) was less than predicted during the first 1 to 12 hours postfeeding, but greater than predicted from 13 to 24 hours after feeding. Several studies have shown that highest producing cows exhibit the greatest sorting behavior. What does this mean relative to the potential for acidosis? Cows lowest in the dominance hierarchy consume more NDF (forage) and less concentrate. So, we need adequate bunk space and proper grouping strategies for fresh cows and primiparous cows. Some producers “feed to an empty bunk” reasoning that this practice will eliminate sorting. And it does, on a group basis. But, do we really know if it eliminates sorting on an individual cow basis? This is an area that requires further research. Sorting can be evaluated using the Penn State Particle Separator. Samples are collected and sieved at feed delivery, at 6-12 hours after delivery, and the refusals just prior to fresh feed delivery. The weight of material on each sieve should be within 8% of the original ration if no significant sorting has occurred. In summary, sorting can depress digestive efficiency by causing subclinical acidosis or negative associative effects, consumption of high forage (NDF) diets, and increased variation in intake and ruminal fermentation. Meal Patterns. Ruminal pH decreases following meals with the rate of pH reduction increasing as meal size increases and as dietary NDF decreases (Shaver, 2002). Feed management practices that contribute to slug feeding (fewer and larger meals) include: 1) limited manger space, 2) limited feed access time, 3) restricted versus feeding for 3 to 5% refusals, 4) inconsistent feeding schedule, 5) infrequent ration push-up, 6) excessive competition for feed, and 7) heat stress. The combination of limited manger space (<0.45 m per cow) and feed access time (<20 h/d) results in a worse situation than either alone. The use of headlocks in situations of limited manger space exacerbates the problem because each lock-up and the cow in it takes up approximately 0.61 linear meters. When overcrowding of free-stalls occurs with limited manger space, the potential for acidosis and laminitis increases because cows will spend more time standing on concrete than lying in stalls. Feed Mixing and Feed Delivery. A study was conducted at Cornell University (Chase, 1998) that evaluated the effect of total mixed ration mixing time on effective fiber content of the diet. The rations contained 46% forage (55:45 corn silage:haylage) and 50% dry matter. During a 5-week feeding trial, the researchers evaluated the effect of 5 versus 30 minutes of mixing. In this trial, coarse particles were reduced from over 12% of the ration down to 4%, and milk fat percentage was reduced from 3.5% down to 2.7%. From this data, we can

calculate that 1) every 3 minutes past 5 minutes of mixing leads to a 1.2 percentage-unit reduction in particles on the top screen, and 2) every 3 minutes past 5 minutes of mixing leads to a 0.1 percentage-unit decrease in milk fat test. Overcrowding and Rumination. Batchelder (2000) evaluated 0 versus 30% overcrowding of stalls and feed manger in a switchback trial on a commercial dairy farm. All cows were fed the same diet. The square meters of space per cow, bunk space, and stalls/cow were all reduced by 30%. The % of cows eating post-milking was 45 to 66% with no overcrowding, but only 30 to 38% with 30% overcrowding. Overcrowded cows preferred free stalls versus eating after milking, and actually spent more time in the alley waiting to lie down than eating! With overcrowding, approximately 28% of cows were ruminating, but nearly 37% were ruminating with no overcrowding. What would be the potential impact of this difference in rumination on ruminal pH? More importantly, in an overcrowded situation, do we need to consider adjusting the forage NDF to NFC ratio to prevent acidosis from occurring? Taking Advantage of Natural Dairy Cow Behavior to Improve Feed Intake: Pulling It All Together Effective troubleshooting of feeding problems requires you to consider the three major activities of dairy cattle – eating, rumination, and resting – and to realize that all three behaviors are interconnected. When resting (lying) and eating activity are restricted simultaneously, cows often choose to rest rather than eat when allowed access to these two resources again (Metz, 1985). In fact, 1.5 hours of extra standing time were associated with a 45-min reduction in feeding time. More recently, Daniels et al. (2003) observed that milk yield on day 8 postpartum was significantly affected by resting time on day 6 prepartum. The implications of this type of behavioral data on transition cow management are immense. We need to focus on the housing conditions and management routines used with dry cows because their comfort and ability to rest will impact feed intake and productivity in that critical time period following calving when the cow is attempting to achieve maximum dry matter intake and maintain health. Dairy Cow’s Daily Time Budget A cow needs to accomplish certain behavioral activities during each 24-h time period – i.e. her daily time budget. Table 6 illustrates a simplified daily time budget for lactating dairy cattle. As you can see, the dairy cow requires about 3 to 5 h/d for consumption of feed, 7 to 10 h/d for ruminating, 30 min/d for drinking, and approximately 12 h/d lying or resting time. Depending on the cow and her environment, the daily feed intake will be divided into 9 to 14 meals. Albright (1993) summarized similar time budget data for a cow (Beecher Arlinda Ellen) during the lactation in which she set a world record for milk production while housed primarily in a box stall.

Table 6. Daily time budget for lactating dairy cow. Activity Time devoted to activity per day Eating 3 to 5 h (9 to 14 meals/d) Ruminating 7 to 10 h Drinking 30 min Milking parlor 2 to 3 h Lying/resting 12 to 14 h

The data indicated that she spent 6.25 h/d eating, 13.9 h/d resting (lying), and 8 h/d ruminating (7.5 h/d while lying and 30 min/d while standing). We conducted a study (Matzke, 2003) recently at University of Nebraska in which we compared the time budget of the top-10% of cows (by milk) in a group versus the group average time budget. These “elite” cows rested for 14 h/d, with very little time devoted to idling in alleys and standing in stalls. It is interesting that these elite cows, as well as Beecher Arlinda Ellen (the first cow to produce >50,000 lb of milk in a lactation), both rested for 14 h/d. One could speculate that the actual requirement for resting is close to 14 h/d, rather than approximately 12 h/d as commonly proposed. In a subsequent section, I’ll present evidence of the importance of resting to cow well-being and productivity, and how she likely has a specific requirement for resting. In fact, I argue that resting is “vitamin R”, rather than rumensin®! It is clear that cows need to accomplish certain behavioral activities each day, and we cannot allow our management routines to interfere. If we tally up the required number of hours each day to satisfy the basic behavioral needs, it approaches 20 h/d: 5 h/d for eating + 11 h/d for lying/resting (includes 6 h of rumination) + 4 h/d for rumination while standing + 30 min/d for drinking. If we add in only 30 min/d for other activities such as grooming and other interactions, the total time required in the budget is 21 h/d (Grant et al., 1990; Grant, 1999). Given this time need, it is easy to see how our management practices can very easily perturb the cow’s normal time budget. Overcrowding and excessive time in holding pens are two common ways of upsetting the time budget. Typically, the first thing that a dairy farmer does each morning is to organize the day’s activities; create a time budget so that all critical activities are accomplished that day in a timely manner. Unfortunately, too many farmers do not consider that the cow also has a list of daily activities that must be accomplished to ensure productivity and well-being. A fundamental question for cattle production is “how often do we take advantage of natural cow behavior versus simply taking advantage of the cow?” Table 6 illustrates several common examples of ignoring natural cow behavior and the management routine that frustrates the cow’s natural behavior. Table 6. Examples of ignoring natural cow behavior. Behavior Management routine Eating with head down Elevated feed bunk Grooming Excessive time in lock-ups Aggressive feeding Infrequent push-ups Resting and rumination Limited access to comfortabl e stalls

Nebraska Time Budget Research Trials

During the past several years, we have conducted a series of on-farm observations to develop realistic time budgets for lactating cow and to measure the impact of selected management routines on these time budgets. In addition, we have observed the behavior of primi- and multiparous cows in commingled groups to determine what strategies heifers may use to accommodate living with older multiparous cows. The studies were conducted on two commercial dairies. Farm A was a 6-row free stall barn (3 rows per group of cows) with headlocks and 89 usable stalls per pen. The herd was milked three times/day and cows were locked in headlocks for 3 hours daily. Farm B was a 4-row free stall barn (2 rows per group) with a post and rail feeding system. There were 150 usable stalls per group. The herd was milked three times daily, and there was a palpation rail outside of the pen. Cows in the experimental pens were observed every 20 minutes continuously for 48 hours (or 72 hours for one period on Farm B). For Farm B, there was a very noticeable effect of time spent away from the pen on resting behavior. During observation 1, cows were spending as much as 7 hours daily away from the pen due to milking because the parlor was too small for the size of the cattle groups; prior to observation 2, the group was split into two smaller groups. The major effect was on resting time which increased from only 36% of the day to 49% of the day. At the same time, milk production in the group of cows increased by nearly 4 kg/d. This increase in milk production reflected greater resting activity. Having properly sized groups of cows relative to parlor size, especially with a management rail, is critical to allow cows adequate time for resting.

Figure 4. Time budget of activities for Farm A showing daily patterns of feeding and resting.

For both dairies, heifers in commingled pens spent more time standing and eating at the manger than older cows. They also spent less time lying in stalls and more time standing in

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the alleys. For Dairy B, when the group was split to reduce time spent away from the pen, time spent lying in stalls increased by 10.7% for multiparous cows, but by 17.4% for primiparous cows. These data suggest that, in commingled groups, management routines that negatively impact time budgets are going to have a much greater negative effect on heifers. Practical considerations raised by this type of research include: time budgeting is important; what are the ramifications of headlocks versus post and rail feeding systems; are commingled groups always counterproductive from the heifer’s standpoint; a simple management change (such as splitting a pen) can have profound effects on behavior and productivity; and do thumb rules apply to every situation or do we need to modify them for the specific set of conditions that exist on every dairy. Rumination and Resting: Cornerstones of Dairy Cow Well-being As early as 1928, researchers were investigating the importance of resting and the implications of adequate lying time for cow comfort, health, and productivity (Fuller, 1928). Recognized benefits of adequate resting activity include: reduced stress on feet, reduced lameness, increased blood flow to the mammary gland, increased feeding activity, and greater overall cow health. The advantages of adequate rumination activity are obvious and involve maintenance of ruminal conditions conducive to efficient microbial fermentation. When cows are resting, approximately 50% of those cows should be ruminating in a well-designed barn, although we have observed considerable variation in well-managed commercial dairies. Although effective fiber usually drives rumination activity, social stress, such as overcrowding and excessive competition for feed and stalls, can reduce rumination and feeding activity. Rumination and Resting Ewbank (1978) speculated that rumination acts as an anti-boredom activity in adult cattle. During the rumination process, considerable self-stimulation and inwardness occurs. When cows are ruminating, whether lying or standing, they are quiet and relaxed with their heads down and eyelids lowered. Although cows can ruminate while standing, they ordinarily lie down with their chests against the ground (Albright, 1987; 1993). The self-stimulatory aspects of rumination may provide the physiological rest and rejuvenation normally provided by deep sleep. Cows spend substantially less time sleeping than do humans, dogs, and horses. Cattle are drowsy for about 7 to 8 h/d (Ruckebusch, 1972). Cassida and Stokes (1986) observed that 55% of total lying time for dairy cattle occurred between 10:00 pm and 4:00 am. Balch (1955) concluded that, if cattle sleep, their sleep is of a short and transient nature. Merrick and Sharp (1971) used electroencephalograph readings to conclude that cattle rest without loss of vigil or consciousness. Ruckebusch et al. (1974) presented evidence that cows do indeed practice rapid eye movement sleep (“true sleep”) in short, 2 to 8 minute periods. In theory, sleep serves two major functions: 1) recuperation for physiological and psychological restoration and 2) increased response thresholds to prevent disturbance of rest from insignificant environmental stimuli. Some recumbency is necessary to prevent fatigue. Cattle deprived of resting (lying down) compensate for loss of rapid eye movement sleep by engaging in non-rapid eye movement (“quiet”) sleep while standing (Arave and Albright, 1981).

Requirement for resting. Cows attempt to maintain a rather fixed amount of lying time, and their well-being is impaired when lying time is restricted for several hours (Metz, 1985). Earlier, the variability in the behavior of individual cows in comfort tests influenced resting habits more than the type of stall – free stall, tie stall, or stanchion. Overcrowding of stalls by 25% can result in reductions in lying time of up to 2 hours. Resting Postures To categorize postural differences in resting dairy cattle, Coe et al. (1990) observed 80 bull calves at 20-min intervals from 1900 to 0330 h at 5, 10, and 17 wk of age. They also observed 68 lactating cows at 15-min intervals from 1900 to 0330 h twice (3 months apart) in winter in two barns in northern Indiana with 40 calves housed in stalls (0.93 m2 each) and 40 in eight group pens. (6.5 m2 or 1.3 m2 each), all with slatted wood flooring. Cows were housed in 64 free stalls (2.8 m2 each) on bedded wood or bedded concrete. As part of a larger study, each calf was observed for various resting postures (Table 6). No significant differences existed between calf postures in stalls or pens, so the data were pooled. For both calves and cows, the results demonstrated that sternal recumbency with their eyes open is the most common resting position. Resting with the head on the neck, leg, or flank is less prevalent in the adult bovine. Lateral recumbency is similar in both calf and adult, but environment may influence this behavior. Upright posture is more prevalent with advancing maturity of cattle. Table 6. Resting postures of cows and calves (% of total observations). Postures Cows Calves ---------(%)------------ Erect, eyes open 74.2 58.6 a Erect, eyes closed 10.0 7.2 a Head on neck 6.2 18.5 a Head on leg or flank 0.4 13.2 a Head on stalls or floor 7.5 0.6 a Lateral, on side 1.7 1.8 aThe t-test for significance ( P <0.01) signified that values for calves were different from cows for various postures excep t lateral recumbency.

Normal Resting Positions To allow for normal resting behavior, the stalls (or other resting area) should provide cows with: 1) ability to stretch their front feet forward, 2) ability to lie on their sides, with unobstructed space for neck and head, 3) ability to rest head against their sides without hindrance from a partition, 4) ability to rest with legs, udders, and tails on platform, ability to stand or lie without fear or pain from neck rails, partitions, or supports, and 6) ability to rest on clean, dry, and comfortable bedding (Anderson, 2002). Anderson (2002) suggests that we need to be concerned with “cow ergonomics”; in other words, the improvement of cow health and performance through the careful design of her work environment. Restrictive stalls can lead to restlessness. Restlessness leads to excessive leg movements and more abrasions. Stall design and maintenance should promote a more restful lying experience to

help prevent hock sores in free stalls (Anderson, 2002). Research indicates that cows with their head on flank are most likely to be experiencing REM sleep (Gerard et al., 1993) and therefore receiving the greatest physiological rest and rejuvenation. Economic Significance of Resting and Rumination: Feeding and Milk Yield Inadequate rumination, especially with the highly digestible diets commonly fed to dairy cattle, will often result in inadequate buffering of the fermentation acids produced and ruminal acidosis occurs. Ruminal acidosis results in lameness and reduced mobility, off-feed problems, reduced milk fat output, poor body condition, and even poorer reproductive performance. The acidic conditions in the rumen result in lower efficiency of milk production. The economic losses sustained on a dairy can be tremendous if the diet is inadequate in effective fiber and rumination suffers. However, we cannot forget that the feeding and housing environment also can affect rumination. Batchelder (2000) observed that rumination was decreased 25% for cows that were 30% overcrowded versus 0% overcrowded, even though they were fed the same total mixed ration. We also know that a majority of rumination occurs when cows are recumbent. So, adequate resting time is key for proper rumination, as well as cow health and productivity. Some suggest (Albright, 2001) that for each hour of resting activity, you can expect approximately two lb more milk production due to improved health and more blood flow through the mammary gland. In our on-farm studies, we’ve observed as much as 3.2 hour/day difference in resting (lying) time due to grouping strategy. Specifically, a group of cows was too large for the parlor capacity and cows spent too much time in the parlor (~20% of the day) and insufficient time resting (36% of day); when the group was split, cows spent less time in parlor (13% of day) and more time resting (49% of day). Interestingly, this herd increased in milk production by approximately 2.7 to 3.2 kg/cow/day after this management change. An on-farm application of this rule of thumb would involve knowing the amount of time cows spent away from their pen each day (i.e. away from stalls, feed, water, and other resources). Analysis of typical time budgets from free stall barns indicates that cows spend approximately 9 hours daily engaged in eating (5.5 h/d), drinking (0.5 h/d), and 3.0 h/d for other activities such as idling, grooming, fighting, and estrous activity. I refer to these activities as “behavioral overhead” because they need to be conducted every day. If one simply adds together the behavioral activities (9 h/d) plus the time spent away from the pen, and then subtracts from 24 hours, the result is a reasonably close estimate of time provided for resting on the farm. This amount should be 12 to 14 h/d. Summary and Perspectives Cows have a naturally aggressive feeding drive that we cannot afford to frustrate with poorly designed feeding facilities or management routines. To allow the cow to attain her target dry matter intake, we need to ensure that the feeding area is properly designed and maintained, that the feeding strategy promotes aggressive feeding behavior and optimal ruminal function, and that our management facilitates adequate resting and rumination activity. Resting affects feeding behavior (and vice versa). The bottom line is that proper feed bunk management encourages natural behaviors by the cow that results in optimal efficiency of production and herd health and well-being.

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Feeding Behavior Troubleshooting Guide �� Measure Dry Matter Intake & Compare with Target DMI by Stage (kg/d):

Dry cows Fresh cows Milk cows

Phase 1 Phase 2 Phase 3 Phase 4 Phase 5 Phase 6 Early dry Close-up 0-21 d 22-80 d 81-200 d >200 d 12.7 10.0 18.1 23.6 22.2 19.0 �� Measure reduction in DMI during 7 days prepartum (often ~30%) and adjust close-up

ration with greater nutrient density �� Measure rate of increase in DMI during first 5 weeks postpartum

o 1.4 to 1.8 kg/wk for primiparous cows o 2.3 to 2.7 kg/wk for multiparous cows

�� Maximum DMI for lactating cows should be at least 4.0% of bodyweight �� Cows reach maximum DMI by 8 to 10 weeks postpartum �� Feed delivered allows for 3 to 5% refusals �� Manger surface smooth and odor-free �� Manger height 4 to 6 inches from floor level where cow stands; avoid elevated feed

bunks to reduce feed tossing and increase saliva flow (rumen buffering) �� Manger slopes less than 3% to avoid cow movement �� Feed alley 14 feet wide �� Is gridlock evident at feeding times? �� Rubber surface on feed alley where cow stands �� Never make cow push hard against feed barrier while eating:

o Is feed pushed up at least 4 times daily prior to when cows exert maximum pressure on feed barrier? and (or)

o Tilt headlocks by about 6 inches at top to increase reach by about 25% �� Do you see rubbed or bruised neck and shoulders? �� Palatable feed available immediately after milking to increase dry matter intake �� Provide at least 2 feet of linear bunk space per cow for milking groups and 0.5 feet for 4

to 8 month old heifers and 1.5 feet for 17 to 21 month-old heifers �� Feed is available to cows for at least 20 hours daily �� Are cows locked in headlocks for no more than 1 hour daily? �� Is forage fed before grain? �� Is concentrate fed at least 3 times daily in component-fed herds