abstracts university of yucatan, mexico merida …seen as flexible and versatile crops for the...

ABSTRACTS

OF THE THIRD ANNUAL MEETING

OF THE

FACULTY OF VETERINARY MEDICINE AND ANIMAL SCIENCE

UNIVERSITY OF YUCATAN, MEXICO

Merida

16, 17 and 18th July, 1980

SECTION 1 Forage Production

SECTION 2 Ruminant Nutrition

SECTION 3 Ruminant Production

SECTION 4 Milk and Reproduction

SECTION 5 Pigs and Poultry

SECTION 6 Biogas

278 Trop Anim Prod 1980 5:3

1. ESTABLISHMENT OF LEUCAENA LEUCOCEPHALA WITH COMPANIONCROPS1: B Pound2, Amarely Santana, & Guadalupe Ruiz, CEDIPCA, CEAGANA,Apartado 1256, Dominican Republic.

Leucaena leucocephala shows great promise as a protein forage for livestock in thetropics. However, one disadvantage is its slow establishment. To make use of the landand to reduce erosion and weed build-up during the first ten weeks, a trial was carriedout to evaluate the effect on establishment and total yield of planting companion cropsbetween the rows of leucaena. The companion crops used and their yields as forage'are shown in Table 1. Their effect on yield from the first two harvests of leucaena areshown in Table 2.

Table 1:Forage yield (x ± SEx) of companion crops

Companion crop Forage yield (kg DM/ha)

Maize 2719 ± 292

Canavalia ensiformisa 2790 ± 340

Sweet potato 1197 ± 219

Cow pea 589 ± 139

a Regrowth yielded a further 1510 and 2880 kg DM/ha in the first and second harvest of leucaena.

Table 2:Leucaena forage yields (kg DM/ha)

Companion crop Harvest

1 2 Total

None 2810 3630 6440

Maize 1290 3010 4300

Canavalia 1030 1580 2610

Sweet potato 1620 3880 5500

Cowpea 2280 4590 6870

1 the support of the FAO/UNDP project DOM/77/002 is acknowledged2 Technical! Cooperation Officer, ODA Great Britain

2. EFFECT OF NITROGEN AND PHOSPHOROUS FERTILIZATION ON THEPRODUCTION AND PERCENTAGE PROTEIN OF THREE NATIVE GRASSESOF THE GENUS PASPALUM IN THE STATE OF TABASCO; J Perez and FMelendez N: CSAI, Cardenas, Tabasco, Mexico

In this study the following native grasses were studied: (Paspalum notatum) and (P.plicatulum) and (P. conjugatum). The first two were grown in acid soils with lowcontent of available phosphorous and clay sandy soil of crum structure. The lastnamed grass was grown in alluvial clay soil of good fertility. Both places had a humid

Trop Anim Prod 1980 5:3 279

tropical climate. The following levels were studied; 0, 100, 200, 400 kg N/ha. (usingurea as the source of nitrogen) and 0, 40, 80, 120 kg of P2O5/ha (as triplesuperphosphate). The N was supplied in split applications, 40% in three applicationsbetween June and November and the rest in four equal parts between December andMarch. Phosphorous was supplied in one application incorporating it in the soil at thestart of the study. Plots of 3 x 5 m were used and the treatments were distributed in afactorial arrangement using a randomised block design with four replications. Cutswere made with a machete between 4-8 weeks depending on the season. Thepercentage of N in the grass was determined by the Kjeldahl method.No significant effect was obtained from Paspalum notatum with respect to N levelwith yields of 15.0, 11.1, 11.8, 14.7 t/ha of DM in two years for 0, 100, 200 and400 kg/ha respectively. Nor were there differences in response to phosphorous,15.0, 10.0, 13.5 and 11.0 t DM/ha being obtained for the levels in the study.The combination of 100 kg of N and 40 kg of P2O5 gave the best result being 16.1t DM/ha. Protein content was increased as phosphorous level increased, thevalues being 7.7, 8.4, 8.8 and 9.9% respectively; hut there was no response todifferent N treatments. Yield of P. plicatulum did not respond to N or to P at the levelsstudied. Protein was increased by N (6.0, 8.5, 9.5, 8.5%) and by P (6.0, 9.0, 9.4,10.7%) Paspalum conjugatum on the other hand responded to N (22.9, 41.9, 42.6,29.3 t DM/ha and also to P (22.9, 37.3, 27.6, 35,8t DM/ha).Protein content increasedwith increasing levels of N fertilizer (8.7, 8.8, 8.8, 10.8%) and increasing levels of P(8.7, 8.8, 9.5, 10.1%). There was a marked effect of season, with greater yields in therainy season compared to the season of northerly winds and the dry season. Theyields of DM/ha for P. conjugatum were superior to those for the other grasses in thetrial, with respect to DM/ha as was the efficiency of utilization of N and P.

3. EFFECT OF TWO LEVELS OF SOIL FERTILITY ON THE PERCENTAGE LEAF

FROM VARIOUS TROPICAL GRASSES IN THE HUIMAGUILLO PLAIN OFTABASCO, MEXICO: J Guadalupe Rivera, F Melendez N and J Perez P. CSAT,Cardenas, Tabasco, Mexico

In a study of eight months duration the percentage of leaf in 7 tropical grasses wasdetermined under two levels of soil fertility; the two levels being NPK at 80-50-0 and160-100-50 in two sites on the Huimaguillo plain in Tabasco State. The design used was a randomised block factorial (2 x 7 x 2) with 3 replications. Therewas a highly significant response to variety ( P < 0.01) and a significant interactionbetween site and variety for the four cuts that were made (P < 0.01). Between sitesthe difference was less in the third cut(P <0.05) than in the fourth cut (P < 0.01) theonly interaction between variety and level of fertilization was in the first cut (P < 0.05)alla in the triple interaction (P < 0.01). The percentage of leaf was very variable withthe highest percentage being obtained from P notatum throughout the experiment.The upright tillering type of grasses gave higher percentages of leaf in the season offastest growth, this parameter diminishing as average temperature decreased whichwas also true when these grasses entered their reproductive phase. The grasses ofstoloniferous habit had a lower percentage of leaf; with less variation than the moreupright grasses.


4. THE EFFECT OF HEIGHT AND FREQUENCY OF CUTTING ON THE YIELD OFAFRICAN STAR GRASS (CYNODON PLECTOSTACHYUS) IN THECHONTALPA REGION, TABASCO MEXICO; F Melendez and J Perez CSAT,Cardenas, Tabasco CO, Mexico

In the Chontalpa region of Tabasco an experiment lasting 240 days was carried outusing African Star Grass. This experimental period included the season of Northerlywinds (November to February) and the dry season (March to May). The treatmentsheight of cutting (0, 5 and 10 cm) above soil level and the interval of cutting (24, 40and 60 days) were compared in a 3 x 3 factorial design with randomised blocks andfour repetitions. Plots of 9 m2 were planted and an area of 2 x 2 m within this washarvested. All the plots received a basal dressing of 300 kg of N/ha/year in 6applications. The production of DM was evaluated per cut as was the total for eachseason. Significant effects (P < 0.05) of season on yields of DM were obtained. Yieldswere higher in the dry season (3.1 t DM/ha) than in the season of northerly winds (1.9t DM/ha), this being attributed to the effect of lower temperatures in the latter seasonand its effect on the development of the grass. In the season of northerly winds therewas a marked effect (P< 0.01) of the height of cutting on yield. In the rainy season theinterval between cuts had a significant effect (P < 0.05) on the production of DM. Fromthe results one concludes that in the season of northerly winds it is better to defoliateat ground level ( 0 cm) with longer intervals between cuts (40 or 60 days) and in thedry season the cuts can be at soil level at intervals of 40 days.

5. THE EFFECT OF HEIGHT AND FREQUENCY OF DEFOLIATION ONFORMATION OF BUDS OF LEUCAENA LEUCOCEPHALA IN THE STATE OFTABASCO MEXICO: Jorge Perez P and F Melendez CSAT, Cardenas, Tabasco,Mexico

An experiment was carried out in the experimental fields of CSAT, Cardenas, Tabascoin soils of alluvial origin with a medium to high fertility although with problems ofdrainage. The experiment lasted one year and the seeds were of a local (Campeche)variety. Plots of one year old leucaena were used and the plot size was 2 x 3 m. Threefrequencies of defoliation ( 4, 5 and 6 weeks) and 3 heights of cutting (30, 40 and 50cm above soil level) were used. Five plants were taken at random and the number ofbuds formed after each cut was counted. The yield of green material per stalks andleaves was measured from its re-birth. A randomised block factorial (3 x 3 ) with 3replications was used. Yields increased as the interval between defoliations increasedand also with cutting height. The highest average production per cut was obtainedwith a treatment combination of 6 weeks between cuts at 40 cm of height (1943kg/ha). The greatest yield was obtained in the rainy season, the lowest yield in thewinter months and intermediate yields in the dry season. Total production of DM wasgreatest with a cutting interval of 4 weeks a height of 50 cm (14598 kg/ha) and leastwith a cutting interval of 6 weeks and a height of 30 cm (8713 kg/ha). The number ofbuds formed was similar for each of the 3 intervals (112), with a tendency to be higherwith a cutting interval of 6 weeks and a height of 50 cm. The worst combination oftreatments was a height of 30 cm at an interval of 6 weeks when the production ofbuds was 89. The formation of buds followed the reverse tendency to that of yieldbeing lowest during the rainy season, highest in winter and intermediate during the dryseason. The greatest formation of buds was with the longest intervals.


6. EFFECT OF HARVEST INTERVAL AND PLANTING DISTANCE ON FORAGEYIELD OF DUAL PURPOSE CROPS1: Angela Fernandez, B Pound2 and LuzMeyreles: CEDIPCA, CEAGANA, Apartado 1256, Sto Domingo, DominicanRepublic

Dual purpose crops (grown for their animal forage and human food components) areseen as flexible and versatile crops for the integrated livestock producer, This trialwhich is still in progress, examines the effects of planting distance and harvest intervalon forage yield and subsequent yield of the human foot components (root/tubers/fruit)for three crops (sweet potato, cassava and plantain). It is apparent from the data inTable 1, that the effect of planting distance is important in the initial harvests of foragefrom cassava and sweet potato, but thereafter the plants compensate for spacingdifferences. However, yield differences are maintained between plantain treatments.

Table 1:Effect of planting distances on forage yield (kg DM/ha)

CropSpacing

Cassava Sweet potato Plantain

Close Wide Close Wide Close Wide

Harvest

First 2570 1010 2240 1500 370 210

Second 2570 2470 1530 860 200 70

Third Not harvested 3050 3170 460 140

1 Support from the International Foundation of Science, Stockholm, Sweden; and the FAO/UNDP Project DOM/77/002 is gratefully acknowledged

2 Technical Cooperation Officer, ODA, Great Britain

7. SOME RESULTS WITH ELEPHANT GRASS (PENNISETUM PURPUREUM) INTHE NORTH CENTRAL REGION OF VENEZUELA; P J Arias; Instituto deProduccion Animal, Facultad de Agronomia, Universidad Central de Venezuela,Maracay

This paper gives results obtained during various years of experimentation withelephant grass in the North central region of Venezuela, The yield of forage with highlevels of Nitrogen (600-1000 kg N/ha/year) has varied from 28 to 95.4 t DM/ha/year.The principal factor which affects the yield is the cutting frequency: 38.9, 71.9 and86.0 t DM/ha/year, cutting at 7, 10 and 12 weeks with an efficiency of conversion ofenergy in the visible spectrum of 2.14, 4.00 and 4.81% respectively. With irrigationapproximately 40% of the yield corresponds to the dry season. The efficiency ofirrigation has improved progressively from 0.63 to 2.0 kg DM/m3 of water applied. Withhigh yield the efficiency of application of N reaches an annual average value of 60 kgDM/kg N. With high levels of N, the content of crude protein in DM at 7 and 10 weeksof age averaged 9.6 and 6.3% with an estimated digestibility of 72 and 65%. With highlevels of N and harvesting at 7 weeks average mean values in sheep were 63.1%digestibility of DM and voluntary feed intake of 2.96 kg DM/100 kg liveweight/d and67.9 g/DM/kg.75 .


With cattle in various experiments, the intake has varied between 2.43 and3.44 kgDM/100 kg liveweight/d. Feed conversion showed extreme values between21.0 and 7.1 kgDM/kg of liveweight gain. Feed intakes close to 2% of liveweight are only sufficient for maintenance and often are accompanied by loss inweight.It is considered that a reasonable estimate of yield is 45-50 t DM/ha/year;a DM intake of 2.7% of liveweight, a digestibility of DM of 62% and a crude proteincontent of 8% with 67% digestibility.Nutrient intake and supplementation is discussed for cows of 450 kg liveweightreceiving a basal diet of elephant grass.

8. CAPACITY OF FERTILIZED BUFFEL GRASS (CENCHUS CILIARIS MEATPRODUC TION IN THE HENEQUEN ZONE OF YUCATAN, MEXICO: MSandoval, INIA, CAEZOHE, Apdo Postal 1485, Suc B, Merida, Yucatan

The objective of this experiment was to determine the capacity of Buffel grasspastures for beef production, 54 Zebu bulls with an initial weight of 265 kg weredistributed at random to a completely randomised design with 2 replications and withtreatments of 3, 4 and 5 animals/ha; a control plot with 3 animals/ha received nofertilizer. The corrals were fertilized with a level of 75-150-0. Water and mineralisedsalt were offered ad libitum. Continuous grazing was used and the animals wereweighed each 14 days during the 196 day experimental period. After 112 days thetreatment with 5 animals/ha was stopped with no difference in gain/animal/day beingapparent. The treatments with 3 and 5 animals/ha had higher daily gains than thatwith 4 animals/ha although the production of beef/ha was the same.

Treatments (animals/ha)

5 4 3 3 (control)

Fertilization rate (N-P-K)

Grazing period, days 112 196 196 196

Initial weight, kg 256 264 269 272

Final weight, kg 348 363 387 393

Weight gain (animal/d) g 822 503 602 619

Total weight gain/animal, kg 92 99 118 121

Beef production/ha, kg 460 394 354 364

9. THE CHEMICAL COMPOSITION OF GLYCINE WIGHTII ENSILED WITHDIFFERENT LEVELS OF FORMALDEHYDE AND IN THE PRESENCE ORABSENCE OF DERINDED CANE1: R Munoz, Margaret Gill2 and AmarelySantana, CEDIPCA, CEAGANA, Apto. 1256, Santo Domingo, Dominican Republic

The use of high protein forages as supplements to diets based on sugar cane hasbeen shown to increase intake and liveweight gain. Owing to the seasonal productionof these forages it would be advantageous to find an efficient means of conservation


to enable a longer period of supplementation. Thus Glycine wightii was ensiled inlaboratory silos, alone or with three different levels of formalin (2.5, 5.0 or 7.5 g/100 gcrude protein). These four treatments were repeated with the addition of 10%derinded cane. Formalin has been used with temperate grass and legume silages toreduce the degree of fermentation, while the addition of sugar in the form of derindedcane should increase the initial rate of fermentation and thus improve fermentationquality.

The forage was ensiled in plastic containers (5 kg weight of forage) for one month.Chemical composition data are given in the Table. The addition of both formalin andderinded cane appeared to reduce the degree of fermentation with some evidence ofinteraction.

Treatment pH Total VFAs(mmole %)

NH3(% DM)

Formaldehyde, g/100 g protein Glycine alone

0 4.5 151 1.12

2.5 4.5 60 0.88

5.0 4.5 49 0.80

7.5 4.7 27 0.52

Glycine + cane

0 4.2 97 0.96

2.8 4.2 71 0.89

5.6 4.3 59 1.23

8.4 4.3 44 1.01

1 The support of the project FAO/UNDP DOM/77/002 is recognised

2 Technical Cooperation Officer, ODA, UK

Ruminant Nutrition

10. EFFECT OF FORAGE AND SUPPLEMENT ON FOOD INTAKE, LEVELS OFGLUCOSE AND KETONE BODIES IN THE BLOOD OF SHEEP FEDMOLASSES/UREA BASED DIETS: E Aranda; Colegio Superior de AgriculturaTropical, Cardenas, Tabasco, Mexico

Twelve Pelibuey sheep of an average weight of 20 kg were randomised to thefollowing four treatments: A) Molasses/urea (2.5%); B) Molasses/urea (2.5%) andcassava meal; C) Molasses/urea (2.5%) and restricted forage; D) Molasses/urea(2.5%), cassava meal and restricted forage. The molasses/urea was offered adlibitum, elephant grass (Pennisetum purpureum) at a level of 1.5% of body weight andcassava meal at 150 g/animal/d. The forage and supplements were offered in


separate feeders and water and minerals were available ad libitum The animals weremaintained in individual cement floored pens in an open sided shed. The experimentlasted 60 d; 36 d adaptation, 20 d to take food intake data 2 d for catheterisation and2d for blood sampling. Blood samples were taken every 2 hr through teflon catheters(# 16) implanted in the jugular vein. The pattern of food consumption was determinedeach 4 hr during the last 2 d.

Molasses/ureaProbabilityNo

supplementCassava

mealRestricted

forageCassava and

forage

DM intake, kg/d

Total .395 .470 .605 .547 .001

Molasses/urea .395 .338 .545 .355 .001

Penultimate 24 hr .522 .418 .786 .390 -

Final 24 hr .170 .206 .520 .215 -

Blood glucose, mg/100 ml 73.8 55.1 58 64.6 .001

Blood ketone bodies, mg/100 ml 2.49 5.38 8.39 1.44 .001.

11. VOLUNTARY FOOD INTAKE ON SISAL PULP DIETS: A Rodriguez, D GHarrison1, E Owen2 and D Wyllie1, INIP, Mococha, Yucatan and Faculty ofVeterinary Medicine, University of Yucatan, Mexico

Four experiments were carried out with Pelibuey rams ranging in weight from 15 to 27kg and adapted to sisal pulp diets for several months to test if sodium or calciumhydroxide could neutralise the pulp and increase the voluntary intake of sisal pulpdiets and to see whether salt or sodium bicarbonate could increase food intakethrough increasing rumen outflow. In each of the first three experiments the dietconsisted of ad libitum ensiled sisal pulp and in the fourth experiment of fresh sisalpulp. Minerals and either soyabean or sunflower meal were added to give a crudeprotein content of 12% in the dry matter. In each of the first three experiments, 15sheep were used, housed individually in cages and in the fourth experiment 10 penseach containing 8 sheep were used. Food intake was measured over 4 - 5 days afteran initial period of 14 - 17 days. Water was available ad libitum. In the first experimentsalt was added to the diet at levels of 0, 10, 20, 30 or 40 g/kg ensiled pulp and in thesecond experiment sodium bicarbonate was added at the same levels. In the thirdexperiment 92 ml of a solution of 0, 7, 10, 13 or 16% sodium hydroxide were added toeach kg of ensiled pulp and in the fourth experiment 0, 1.5, 3.0, 4.5 and 6.0 g ofcalcium hydroxide were used. The additives were mixed just before feeding, except forthe sodium hydroxide, which was added 24 hr before. The results show that


neutralisation of the pulp by the use of either sodium hydroxide or calcium hydroxidehad no beneficial effect on food intake, suggesting that the acids present in the pulpwere not inhibiting intake. Additional salt or sodium bicarbonate increased waterintake, but did not increase food intake in the manner reported in the literature forconcentrate diets, There is a suggestion that the use of sodium bicarbonate might beworthy of further investigation.

Level of additive, g/kg sisal pulpSEx Sig.0 10 20 30 40

Experiment 1 (Salt) .Intake of fresh diet, g 4523 4306 4035 3578 2863 282 Linear**Water intake,g

353 1825 2601 3291 3300 479 Linear**

Experiment 2 (Sodium Bicarbonate)Intake of fresh diet, g 3685 3336 3768 3899 3901 264 -Water intake,g

1000 1544 1811 2267 2511 268 Linear**

Experiment 3 (Sodium hydroxide)0 6.4 9.2 -12.0 14.7 SEx -

Intake of fresh diet, g 2356 2524 1710 1595 1111 287 Linear**Experiment 4 (Calcium hydroxide)

0 1.5 3.0 4.5 6.0 SE -Intake of fresh diet,g 3825 3925 3613 3725 3413 70 Linear**

1 Technical cooperation Officer, ODA, London

2 Faculty of Agriculture, University of Reading England

12. THE USE OF SULPHURIC ACID AS A PRESERVATIVE OF ANIMALFEEDSTUFFS IN THE TROPICS: E Aranda, CSAT, Cardenas, Tabasco Mexico

The efficiency of sulphuric acid as a preservative was tested using 480 kg of freshcattle blood and 540 kg of green plantains, The treatments were as follows with threereplications and using the fresh materials as control: a) for blood, sulphuric acid levelsof 40, 60, 80, and 100 ml/kg of fresh blood in concentrations of 20 and 50%. b) forplantains 150, 200,250, 300, 500 ml of 20% sulphuric acid/kg fresh plantain and 40,60, 80, 100 ml of 50% sulphuric acid/kg fresh plantain. The cattle blood was obtainedat the moment of killing and the plantains were obtained in bunches and cut with amachete. An average of 20 kg of each material was put in plastic bags (capacity 30kg) with addition of sulphuric acid according to treatment and the bags were shakenfor 5 minutes daily over a period of 40 d.


Samples were taken at the beginning and end of the experiment to determine drymatter (DM), crude protein (CP) and protein solubility for blood and DM, CP and crudefibre (CF) and soluble carbohydrate for plantain, Analyses were made according toAOAC methods. pH was determined at the start and 1,2, 3, 4, 5, 10, 15, 20, 30, and40 days using a Beckman Zeromatic 11 potentiometer, The results are presented inthe Table.

Table 1: Effect of sulphuric acid on preservation of cattle blood

Control50% H2SO4 (ml/kg)

40 60 80 100

pH 6.95 2.60 2.38 2.20 2.12

DM (%) 21.3 22.3 23.2 20.9 25.7

Crude protein (%) 93.8 84.8 78..9 75.7 NA*

Soluble protein (%) 20.04 7.47 7.35 6.60 9.04

* Not AvailableThe material preserved with 20% sulphuric acid had putrefied by the 8th day and hence the results arenot given.

Table 2:Effect of acid on the preservation of bananas

Control20% H2SO4 (ml/kg) 50% H2SO4 (ml/kg)

150 200 250 300 500 40 60 80 100

pH 6.67 1.82 1.74 1.76 1.75 1.75 2.33 2.11 2.04 1.99

DM (%) 19.3 17.7 18.6 19.6 19.0 19.3 21.2 22.1 24.6 26.4

Crude protein (%) 5.9 5.7 5.9 5.7 6.3 5.1 6.5 5.7 5.2 4.6

Crude fibre (%) 5.4 6.2 4.7 2.2 3.3 .3.2 3.6 2.6 4.2 4.2

Solublecarbohydrate (%)

1.0 NA* NA NA NA NA 3.0 5.8 6.0 6.5

* Not available

13. THE FERMENTATION OF SUGAR CANE JUICE WITH DIFFERENT LEVELS OFFORMALIN AND UREA1: Milagros Bobadilla, and Margaret Gill2; CEDIPCA,CEAGANA, Apartado 1256, Santo Domingo, Dominican Republic

The use of sugar cane juice in animal feeding systems has resulted in high rates ofliveweight gain. However, fermentation of the juice is very rapid and it is essential tofind economical means of preserving the juice prior to proposing practical feedingsystems. Thus, the possibility of using formalin as a preservative was studied in thelaboratory. In addition, since it is necessary to add urea to the juice to ensure efficientuse of the sugars the effect of urea on the rate of fermentation was also studied,Significant fermentation of the juice started between 6 and 9 hr after extraction, withvolatile fatty acid (VFA) concentrations rising to over 50 meq/liter and pH falling to 3.4


after 24 h. Some fermentation occurred on all levels of formalin addition reducing pHfrom 5.2 (fresh juice) to 4.9 with VFA rising to 15 meq/liter. Further fermentation wasdelayed for 24 hr by addition of 0.01% Formaldehyde. In contrast to a slow initial risefollowed by a continuing rise in VFA concentration, ammonia concentration increasedslightly for the first 6 hr and was then stable for at least 72 hr. Addition of urea at 0.8%appeared to increase slightly the VFA production but loss as ammonia was minimal

1 The FAO/UNDP PROJECT DOM/77/002 is acknowledged for support of this work

2 Technical Cooperation Officer, ODA, Great Britain

14. RATE OF BREAKDOWN OF SUGAR CANE FIBRE TREATED WITH SODIUMHYDROXIDE AND ITS EFFECT ON RUMEN METABOLISM: A Priego and J MZuleta, Colegio Superior de Agricultura Tropical, H Cardenas, Tabasco, Mexico

Four Brown Swiss bulls of approximately 500 kg live weight with rumen cannulae were used in a 4 x 4 latin square design. Each experimental period lasted 16 days. Onday 10 of each period, 6 nylon bags were inserted into the rumen containing 7 g ofsugar cane treated with NaOH. One bag was removed each 24 hr to determine rate ofdisappearance. On day 13 samples of rumen liquid were taken and rumen pHmeasured 0, 3 and 6 hr after feeding. On day 15, 100 g PEG were infused to measurerumen flow rate. The basal diet was sugar cane stalks treated with NaOH at levels of0, 2, 4 and 6% of cane DM (corresponding to 0, 3, 6 and 9g/kg of fresh cane). Eachanimal also received l kg/d of 75:25 mixture of coconut meal: blood meal. Salt,minerals and water were offered ad libitum. The results are shown in the Table. Theeffect of sodium hydroxide increased fibre degradation in the rumen and increasedfood intake by up to 18% with an indication of an increase in rumen flow rate.

NaOH, g/kg Cane DMSE Probability0 20 40 50

Rumen pH0 hr 6.76 6.88 6.95 6.97 .038 .053 hr 6.61 6.76 6. 91 6.90 .020 .0016 hr 6.46 6.71 6.72 6.81 .073 .07Rumen functionVolumes litres 53.3 62.2 51.1 71.8 7.3 .25Flow, litres/d /d 93.3 112 123 144 20 .25Turnover rate,Vol/d, 1.8 1.8 2.5 2.2 .20 .18Rate of degradationT 1/2 (h) 289 158 136 114 34 .05Intake, Kg/dFresh cane 22.0 25.4 27.0 27.0 .68 .007Total DM 7.8 8.6 9.2 9.5 .17 .001Consumption index,kg DM/100 kg 1.5 1.7 1.8 1.9 .04 .025


15. RUMEN FERMENTATION AND FUNCTION IN STEERS FED MOLASSES/UREAAND FIVE DIFFERENT FORAGES: R Godoy, FMVZ, Universidad de Yucatan, Mexico.

Forage is indispensable in molasses/urea diets in order to prevent toxicity. However,there is no strict definition concerning the composition and rumen digestibility of aforage considered to be adequate for such diets. A latin square design was used torelate composition and rumen degradation rate of five forages with rumen functionand nutrient flow to duodenum. The forages were Sweet Potato, Cassava, Leucaena,Banana and Sugar Cane. They were given at the rate of .5% (DM) of live weight in abasal ration of molasses/urea. All the animals received 300 g/d of fish meal and 50g/dof salt and minerals. There was a negative relationship (r2 = .72) between the proteincontent and the cell wall content of the forages which we studied. Rumen degradationrate expressed as half time was related (r2 =.71) to the acid detergent fraction of theforage. The different forage sources did not affect DM intake nor the volume orturnover rate of rumen fluid. Ammonia and rumen pH also showed no difference. Theflow of DM to the duodenum was related to the half life and the content of lignin of theforage (r2 = .78 and .62 respectively). The flow of N to the duodenum was significantlygreater when Leucaena was the source of forage (2.58 g N/100 g OM consumed).When the supply of forage in molasses/urea diets is very restricted' then it appearsthat the type of forage has little significance. Under these conditions it is important toselect forage with a high content of protein and with a fibrous fraction that is degradedslowly in the rumen.

The financial assistance of IFS, Sweden is gratefully acknowledged.

16. STUDIES ON THE RUMEN FERMENTATION PATTERN IN CATTLE RECEIVINGDIETS BASED ON CHOPPED WHOLE SUGAR CANE OR SUGAR CANE JUICE1

Angela Fernandez, Margaret Gill2 Fausto Done and T R Preston3 CEDIPCA,CEAGANA, Apartado . 1256, Sto Domingo, Dominican Republic

The pattern of rumen fermentation was studied in 16 fistulated bulls, 6 of whichreceived a basal diet of sugar cane juice, 6 received chopped, whole sugar cane and4 received liquid molasses as the basis of the diet. Half of the animals receiving juiceand whole sugar cane also had cottonseed meal (1000 g/d for juice and 750 g/d forsugar cane). The animals receiving molasses also had access to protein forages ofleucaena, glycine, pare grass and sugar cane tops (1 animal on each forage). Theanimals receiving sugar cane juice also had restricted quantities (2% of liveweightfresh basis) of leucaena forage. After a period of adaptation to the experimental diets,samples were taken of rumen fluid at intervals during 24 hr. The principal results arepresented in Table 1. There were important differences in the parameters of rumenfermentation between sugar cane juice and whole sugar cane. pH was lower and theconcentration of VFA higher on cane juice than on whole sugar cane. There was a lowpopulation of entodinium protozoa on the cane juice and sugar cane; there was a highpopulation of holotrich protozoa in the chopped whole sugar cane but none in the dietof cane juice. The VFA pattern on cane juice was similar to that found normally incattle receiving molasses.


Table 1:Rumen fermentation pattern (x ± Sex)

Whole sugarcane

Cane juice Molasses

pH 6.45 ± .04 5.99 ± .05 6.42 ± .03

VFA, m-eq/litre . 78 ± 5 142 ± 23 110

Protozoa , x10-5/ml

Holotrich 0.51 ± .07 None None

Entodinia 1.20 ± .19 1.55 ± .23 -

VFA, % Molar

C2 64.1* 52.5 ± 3.8 56.9*

C3 24.0* 22.2 ± 1.0 23.0*

C4 12.0 25.0 ± 1.8 21.0*

*From Fernandez et al 1980 TAP 5:841 The FAO/UNDP Project DOM/77/002 is acknowledged for support of this work2 Technical Cooperation officer, ODA Great Britain3 FAO Consultant in DOM/77/002

17. EFFECT OF PROTEIN SUPPLEMENT AND FORAGE SOURCE ON VOLUNT-ARY INTAKE OF SUGAR CANE JUICE1: Margaret Gill2, Fausto Done and T RPreston; CEDIPCA, CEAGANA, Apartado 1256, Sto domingo, Dominican Rep.

Two trials were carried out to measure the effects of a protein supplement (cottonseedmeal) and two sources of forage (sugar cane or pare grass) on the voluntary intake offreshly extracted sugar cane juice supplemented with 0.5% of urea. In the firstexperiment eight animals were used fitted with rumen and duodenal cannulas, Allanimals had free access to the auger cane juice/urea solution and in addition receivedfreshly harvested leucaena forage at the rate of 2% of body weight daily, Half of theanimals received 1 kg/d of cottonseed meal. After a preliminary period of one weekintake was measured over four consecutive weeks. In the second experiment eightbulls were used all had access to the sugar cane juice/urea together with 750 g/d ofcottonseed meal. Four bulls received freshly chopped whole sugar cane at the rate of5 kg/d while the remaining four had freshly chopped pare grass also at 5 kg/d.Animals in both experiments received 60 g/d of minerals.

Table 1 :Intake of sugar-cane juice (% liveweight/day)

Expt. 1 Cottonseed meal

Withoutsupplement SEx Probability

Week 2 7.00 5.08 ±.50 .01 3 7.20 5.40 ±.54 .01 4 7.21 6.81 ±.31 NS 5 7.45 7.13 ±.67 NS


Table 2:Intake of sugar cane juice (% liveweight/day)

Expt.2 Grass Sugar cane SEx Probability

7.18 5.80 ±.48 .09

The results (Table 1) show that there were significant differences in voluntary intake ofsugar cane juice during the first two weeks of experiment 1, the animals receivingprotein supplement having higher intakes. However, by week four these differenceshad disappeared. The better results with the protein supplement in the early stagescould be ascribed to the direct effects of the by-pass properties of the cottonseedmeal while the improvement in intake on the unsupplemented treatment may wellreflect adaptation of the rumen microbial population leading to increasing efficiency ofmicrobial protein synthesis.. The results (Table 2) in experiment two indicatingsignificantly higher consumption of sugar cane juice with grass as the forage sourcerather than sugar cane confirm previous observations on these two forages.

1 Acknowledgement is made to the FAO/UNDP Project DOM/77/002 for the support of this work2 Technical Cooperation Officer, ODA, Great Britain3 FAO consultant in DOM/77/002

18. SUGAR CANE JUICE AS ANIMAL FEED, COMPARISONS WITH MOLASSESFOR MILK PRODUCTION IN DUAL PURPOSE CATTLE ; O Vasquez, MargaretGill and T R Preston3; CEDIPCA, CEAGANA, Apartado 1256, Sto Domingo,Dominican Republic

Six crossbred cows and their calves (Holstein X Zebu) were used to compare sugar cane juice and molasses as the energy source. The cows were in the second month of lactation and had similar levels of production. Before beginning the trial, the cows hadfree access to molasses (2.5% urea), restricted amounts of sugar cane (2% ofliveweight) and restricted grazing (6 hr/d) on pasture. The treatments consisted ofperiods of 15-17 d during which the experimental diets were offered as indicated inthe Table. The experimental period began on the day 32 when half of the cows werechanged from molasses to fresh sugar cane juice (0.8% of urea) with a Brix! valuebetween 16 and 19. The cows were milked once daily allowing the calf to stimulatemilk letdown and subsequently to consume the residual milk. The total milk production(the amount at milking, plus that consumed by the calf; weighing before and aftersuckling) was measured daily. The results are given in Table 1. Daily productiondecreased when sugar cane was the only forage and was lower with cane juice thanwith molasses. When grazing was reintroduced the yield of milk rose rapidly on thejuice and molasses with an indication that the rise was more rapid on juice than onmolasses. The calves which were suckled by the cows receiving juice grew morerapidly (332 g/d) than those suckled by the cows receiving molasses (171 g/d).

1 Acknowledgement is made to the FAO/UNDP Project DOM/77/002 for the support of this work2 Technical Cooperation Officer, ODA, Great Britain3 FAO consultant in DOM/77/002


Table 1:Daily milk yield in crossbred cows given molasses and cane juice and either sugar cane and/or pasture

milk yield. kg/dPeriod (d)Molasses Molasses

Pasture/sugar cane 7.95 7.34 0 - 15

Sugar cane 7.56 6.36 16 - 32

Molasses Cane Juice

Sugar cane 6.2 4.36 33 - 44

Pasture/sugar cane 6.99 5.89 45 - 59

Pasture 7.47 6.69 60 - 74

Molasses Molasses

Pasture 7.35 6.06 75 - 88

Ruminant Production

19. EFFECT OF THE ADDITION OF NITROGEN AND ENERGY TO FRESH SISALPULP ON THE GROWTH OF PELIBUEY SHEEP IN CONFINEMENT: ARodriguez, A Castellanos, Guadalupe Bernal and A Shimada: INIP, Mococha,Yucatan and Department of Nutrition and Biochemistry INIP, Palo Alto, Mexico,DF

Two experiments were carried out with growing Pelibuey sheep fed a basal diet offresh sisal pulp. This was supplemented with: A) 2 sources of nitrogen (urea orsoyabean meal); b) 2 sources of energy (Sorghum- cane molasses). In eachexperiment 84 Pelibuey rams were used distributed at random to 4 treatments with 3replications per treatment and with 7 animals per replication. Each experimental periodlasted 140 days, In the first experiment 31.8, 64.2 or 100% of the non protein nitrogenin the diet (urea together with a mixture of branched chain fatty acids) was substitutedfor protein nitrogen (soyabean meal). In the second experiment, a 2 x 2 factorial arrangement of treatments was used, in which two energy sources (sorghum andmolasses) were compared with the effect of additional branched chain fatty acids (isoacids). In the first experiment there was a significant linear increase in daily gain and in drymatter consumption as the proportion of protein nitrogen increased. In the secondexperiment the use of sorghum significantly improved daily gain (P< .01).There was no effect due to the use of iso acids. None of the treatments significantlyaltered dry matter consumption.


20, RESPONSE OF GROWING PELIBUEY SHEEP TO VARYING LEVELS OFDIETARY ENERGY: R Gomez, and J Hernandez, INIP, Tizimin, Yucatan, Mexico

Thirty two Pelibuey rams of average weight 16.4 kg were distributed at random to 4treatments with energy contents of 2.16, 2.42, 2.67 and 2.92 Mcal ME/kg (on a drymatter basis). The diets were formulated using sorghum grain, dried grass, soyabeanmeal, urea and molasses. The energy concentration was altered by varying theproportions of sorghum and grass. The diets were iso nitrogenous (15.2% CP in DM)and feed intake and liveweight gain were measured for 70 days. There was asignificant linear increase in daily gain as energy increased; Y= 1.41 + 6.1x (r=0.76) aswell as an increase in dry matter intake and an improvement in feed conversionefficiency.

Diet energy, Mcal/kg2.16 2.42 2.67 2.92

Daily gain g/d 81 109 167 152DM consumption, g/d 783 787 864 868Conversion, feed/gain 9.6 7.2 5.8 5.7

21. THE USE OF POULTRY LITTER AS A SOURCE OF ROUGHAGE ANDFERMENTABLE NITROGEN IN A DIET BASED ON MOLASSES1: Luz Meyreles andT R Preston2 CEDIPCA, CEAGANA, Apartado 1256, Sto Domingo, Dominican Rep.

Eight Zebu steers in individual stalls were used to compare two levels of poultry litterand two methods of feeding in a trial lasting 84 d. The design was a factorialarrangement of the treatments (2 x 2) with two replications. The treatments were: 1.5or 3.0 kg/d of poultry litter; and giving the poultry litter and molasses in separatetroughs or combining the two components by pouring the molasses on top of thepoultry litter. The poultry litter was from a broiler operation and the litter was composedof sugar cane bagasse. The dry matter content was 80% and there was 22% of N x6.25 in the DM. The molasses contained 2.5% urea (w/w). In addition all the animalsreceived 1 kg/d of whole cottonseed. All animals received a mineral mixture. The principal results are presented in Table 1. Total voluntary intake was reducedwhen the higher level of poultry litter was given. Intake was also lower when thepoultry litter and molasses were given mixed together as compared with being givenseparately. The best treatment was the level of 1.5 kg/d of poultry litter givenseparately from the molasses which supported a liveweight gain of 780 g/d and a foodconversion of 7.11 kgDM/kg gain.


Table 1:Mean values for animal performance according to the principal treatment effects

System Poultry litter, kg/dSExSeparate Mixed Prob. 1.5 3.0 Prob.

Daily gain, g 579 169 .001 461 286 .01 ±90

Intake kg!/d

Molasses 4.5 2 89 .001 8.74 2.30 .001 ±.09

Poultry litter 1.25 .83 .05 .66 1.42 01 ±.14

Total DM 5.09 3.76 001 5 04 3 80 .001 ±.17

Conversion 13.3 27.7 .22 23.0 17.9 .26 ±7.0

1 Acknowledgement is made to the FAO/UNDP Project DOM/77/002 for the support of this work2 FAO consultant in DOM/77/002

22. EFFECT OF SUPPLEMENTATION WITH MOLASSES/UREA OR BLOOD MEALON THE PERFORMANCE OF BULLS GRAZING ALEMAN PASTURE: A Navarro,Colegio Superior de Agricultura Tropical, H. Cardenas, Tabasco, Mexico

Fifty four crossbred bulls were allotted to the following three treatments: A) Continuous supplementation; B) Supplementation in the critical period; C) Withoutsupplementation. The animals grazed continuously a total of 15 ha of Aleman grass(Echinochloa polystachya) divided into 6 equal-sized paddocks. The grass wasfertilized with 150 kg 1/ha in three applications. A stocking rate of 2.5 animals/ha wasused in the cool/wet season "nortes" (Oct-Feb) and 3.6 animals/ha during the dryseason (Fete-June). The continuous supplementation treatment consisted of 3.0 kg ofmolasses/urea (2.5%)/d during the season of the "nortes" and 300 g/d of blood mealduring the dry season. The treatment of supplement during the critical period only was3.0 kg/d molasses/urea (2.5%) during the season of the "nortes". Water and mineralswere offered ad libitum. The experiment lasted 224 days (126 d in the "nortes" and 98d of dry season).

The principal results are given in the Table.

Liveweight gain (g/d)Supplementation

Prob.Continuous Critical periods None

Cool/wet (Oct-Feb) 373 316 148 .01

Dry (Feb-June) 663 577 496 .05


23. THE EFFECT OF RESTRICTED ACCESS TO LEUCAENA LEUCOCEPHALA ONLIVEWEIGHT GAIN IN ANIMALS GRAZING AFRICAN STAR GRASS(CYNODON PLECTOSTACHYUS. K. Scherm). J. Palomo S1, R. Castro G., F.Melendez N. CSAT, Cardenas, Tabasco, Mexico

An evaluation of the response to restricted access to Leucaena leucocephala wasmeasured in a 252 day trial at CSAT in Cardenas. The treatments were 0, 2, 4, or 6 hgrazing leucaena with the remaining time spent grazing African Star Grass (C. Plectostachyus) There were 4 paddocks (of 1 ha ) of African Star Grass and 3 compact areas of leucaena (9000 m ). These were grazed by 20 weaned calves (Zebux Holstein and Zebu x Swiss) with an average weight of 115 kg. The stocking ratewas 5 head/ha. in a system of continuous grazing. There were no significanttreatment differences in daily weight gain, however, there was a tendency to increase liveweight gain as the time of grazing leucaena increased. The calves grazing only Star Grass had a total gain of 74 kg, while those with 4 h on leucaena had a gain of 104 kg/animal over the same period. The production of meat/ha followed the same tendency with the best production (547 kg/ha) from animals grazing leucaena for 4 h/d and only 369 kg/ha on the control, There were no signs of mimosine toxicity and itis suggested that restricted grazing of leucaena eliminates this risk.

1 National Institute of Agriculture Research.

24. SUGAR CANE JUICE AS CANE FEED: COMPARISONS WITH MOLASSES INTHE PRESENCE OR ABSENCE OF PROTEIN SUPPLEMENT: M Sanchez & T R Preston1, Facultad de Medicina Veterarinaria y Zootecnia, Universidad deYucatan, Merida, Mexico

Sugar cane juice has important characteristics as an energy containing feed sourcefor animals within the general framework of a better utilization of the sugar cane plant.The experiment reported here was conducted to obtain preliminary information onanimal response to diets based on sugar cane juice in comparison with molassesbased diets. Sixteen steers with a mean initial live weight of 271 kg were distributed inpairs to 8 pens. The dietary treatments (replicated twice) were: A) sugar cane juiceplus urea (0.5%) with a supplement of 1 kg/d sunflower cake; B) sugar cane juice plusurea without supplement; C) molasses/urea (2.5%) with supplement of 1 kg/dSunflower cake; D) molasses/urea (2.5%) without supplement. Both the sugar canejuice and the molasses were offered on an ad lib basis. Chopped African Star Grasswas used as the forage source on all diets (3% of body weight). Minerals were alsofed. Feed refusals were measured daily. The animals were weighed et the beginningof the trial and at 15 d intervals. The trial lasted 75 days. Daily liveweight gains weregreater on the sugar cane juice than on the molasses diets. This may be due to agreater efficiency of conversion of the dietary sugars into microbial protein. Sunflowermeal supplements resulted in an increase in dietary solids intake from juice and agreater liveweight gain on both molasses and juice.


Molasses Cane juiceSEx ProbNo

Suppl.Sunflower

mealNo

SupplSunflower

meal

Liveweight gain, kg/d 0.252 0.595 0.795 1.315 ±.17 .001

Intake, kg/d

Juice 22.7 31.9

Molasses 3.95 4.00

Total DM 5.44 6.42 5.85 8.43 ±.22 .001

Conversion 21.5 11.8 7.42 6.44 ±.57 .001

1 TCO, ODA, London, UK

Lactation & Reproduction

25. ESTROUS SYNCHRONIZATION WITH CHAROLAIS IN A DRY TROPICALCLIMATE TREATING ONCE OR TWICE WITH PROSTAGLANDIN F2 ; J MPonce de Leon S de los Santos, R Ruiz and E Gonzalez, INIP, Palo Alto, Mexico D F and "E! Canelo" Ranch, Tamaulipas

The degree of estrous synchronization and fertility were evaluated after one or twoapplications of prostaglandin F2 (PGF2 ). These were given intramuscularly toCharolais cattle in which a corpus luteum was detectable by rectal palpation. 28 cowsand 28 heifers were distributed into three equal lots on the basis of liveweight, bodycondition ant reproductive state. Three treatments were applied: (1) Application on thefirst day of the study, of 30 mg PGF2 (Dinoprost-trometamina ); (2) As above, butwith a second injection given 11 days after the first; (3) Without hormonal treatment.The dates of the first application in treatment 1 and the second in treatment 2 aretaken as day zero for artificial insemination. Pregnancy was detected by rectalpalpation.

The percentages of heat observed in the first 5 days were 88.9, 78.9 and 31.6%for treatments 1, 2 and 3, respectively (P < .05) and from 0 - 21 days were 100, 94.7and 100%. Fertility from 0 - 5 days was 44.4, 31.6 and 21% (P < .05) and from 0 - 21days was 61.1, 68.4 and 89.5% (P < .05).


26. SURVEY OF CATTLE IN THE STATE OF YUCATAN: J C Segura, ColegioSuperior de Agricultura Tropical, Cardenas, Tabasco, Mexico

The present study was started in 1974 to obtain information on beef cattle in the stateof Yucatan and involved a questionnaire sent to 8,4% of farmers. The state wasdivided into 3 zones (livestock, sisal and agricultural) and these in turn were dividedinto 3 subdivisions according to ownership: individual, group or co-operatives.From the information collected meat production (97.1%) was the principal objectivewith the majority of farmers fattening calves (75.3%) Milk production represented1.6%. One of the principal problems for the farmers was the absence of extensivegrassland in 33.9% of the enterprises sampled, this percentage being greater inco-operatives (85%) and individuals (33.6%).The cooperatives reported worse management in their herds in terms of feedsupplementation and its control, disease and parasite control, crop production, calvingproblems etc. The only genetic tendency observed was the move towards Zebucattle. 50.8, 15.2 and 5.3% of the co-operatives, individuals and groups used theirown calves as bulls.The problems observed thus appeared to be limiting livestock production in the State.

27. PRODUCTION OF MILK IN THE TROPICS: ADVANCES IN THE PRODUCTIONOF MILK AND BEEF IN DUAL PURPOSE SYSTEMS; F J Alvarez, G Saucedoand A Arriaga, Centro Demostrativo de Produccion Animal C- 41, Banco de Mexico, Tabasco

The data presented were collected from a dual purpose herd of Holstein x Zebu cows kept under grazing management in Tabasco, The production and reproduction datarefer to the period 1977 up to the present. The system is typical of dual purposeherds with the presence of the calf to stimulate milk letdown and to remove theresidual milk after milking. There was an increase in milk production from 1000 litresmilk per lactation in 1977 to 1800 litres in 1980. This improvement was attributed tothe culling of non-productive cows, better management and supplementation withsugar cane, molasses and protein during critical periods. The reproduction data showan important improvement which could be attributed to the change in breeding policy.In 1976 only artificial insemination was used while in 1977 natural service was introduced for cows which returned to service twice or had a period of 150 d without apparent signs of oestrus.

28. MILK PRODUCTION IN THE TROPICS: MILKING WITH AND WITHOUT THECALF AND WITH AND WITHOUT SUPPLEMENTATION WITH LEUCAENALEUCOCEPHALA F J Alvarez, J de Leon y A Ayala; Centro Demostrativo de Produccion Animal, Teya, FIRA, Banco de Mexico

This trial was carried out with 34 cows all in their first lactation, representing approximately 75% European genes and 25% Zebu (Holstein X Zebu and BrownSwiss X Zebu). The animals began the experiment at the moment of calving. Theprincipal treatments were as follows: with and without the presence of the calf and restricted suckling, with and without supplementation with restricted grazing of leucaena. The design was a factorial arrangement . The cows were fed on the basis offree grazing, principally on Santo Domingo Star grass, under conditions of irrigation


and moderate fertilization. They also received 3 kg/d of a protein supplement duringthe first 3 months which was later reduced to 2 kg/d. Milking was by machine twicedaily, the protein supplement being given at the time of milking. During the fourmonths, the cows on the restricted suckling treatment, suckled their calves twice daily,after each milking for a period of 30 minutes. The calves on artificial rearing received 4litres daily of milk during the first two months, three litres daily in the third month andtwo litres daily in the fourth month, when they were weaned. The treatment withLeucaena forage consisted in allowing the cows to graze a compact area of Leucaenafor four hours daily in the morning, after milking. Data are given for 172 days oflactation.

Grazing Milking

Leucaena Pasture With calf Without calf

No. of cows 19 15 18 16

Milk production1 (litres/d)

By machine 11.0 10.9 10.8 11.2

Total 13.82 11.2

Liveweight changes (g/d)

Cows -27 16 -59 31

Calves 604 564

1 Preliminary data for 172 days2 Including 2.57 litres/d taken by the calves

29. MILK PRODUCTION IN THE TROPICS; REARING OF CALVES ON TWOMANAGEMENT SYSTEMS, WITH AND WITHOUT LEUCAENA FORAGE: F JAlvarez, J de Leon and A Ayala; Centro Demostrativo de Produccion Animal,Teya, FIRA, Banco de Mexico, Merida

This experiment was carried out with 26 crossbred calves (Holstein X Zebu ant BrownSwiss X-Zebu, approximately 80% European genes) of both sexes and of 3 - 4months of age at the beginning of the trial. The calves had been raised by twosystems of management: artificial rearing and restricted suckling. These two systemswere maintained throughout the experiment. In each system, half of the calvesreceived Leucaena forage, given at the rate of 2 - 3% of liveweight together withmolasses/urea (2.5%) on a free choice basis. They also received 300 g/d of a proteinsupplement. The second treatment was grazing (8:0D am until 3:00 pm) together with600 g/d of protein supplement and molasses/ urea (2.5%) ad libitum. In the group ofcalves reared artificially, some animals (the younger ones) continued receiving milk ata rate of 2 - 3 litres daily until they reached four months of age, when they wereweaned. The calves in the system of restricted suckling were suckled once daily, afterthe afternoon milking. Data are presented for the first 85 days of the trial.


Feeding ManagementSExLeaucaena Pasture Restricted

sucklingArtificialrearing

Liveweight gain, g/d 545 602 635 519 ± 62

Intake, kg/d

Molasses/urea 1.56 1.17

Protein supplement .40 .80

30. MILK PRODUCTION IN THE TROPICS: PRELIMINARY OBSERVATIONS ONPERFORMANCE OF JERSEY AND THREE QUARTER ZEBU/SWISS: A Libreros,C Bermejo, and F J Alvarez; Centro Demostrativo en Produccion Animal “LosSabidos”, Chetumal Q Roo, Mexico.

Preliminary information is presented on 52 Zebu-Swiss and 27 Jersey cows whicharrived in September 1979, The cows were grazing African Star grass pasture. Aftertheir arrival severe outbreaks of anaplasmosis and piroplaemosis were observedmainly in the Jersey herd. After first parturition the cows were mechanically milkedtwice daily without the presence of the calf. After the second milking the calves wereallowed to suckle the residual milk. No decrease in yield was observed without thepresence of the calves. The cows were milked once daily for the first 30 dayssubsequently changing to twice daily.

Table 1:Observations on adaptation to ticks in Swiss/Zebu and Jersey heifers

Total ana and/or piroplasmosis

Affected Death

Swiss/Zebu 52 15 0

Jersey 37 27 2

Table 2:Observations on milk production in Jersey and Swiss/Zebu cows in restricted suckling systems

Once daily milking2 Twice daily milking2

Jersey Swiss/Zebu Jersey Swiss/Zebu

No. of animals 7 3 7 3

Milk yield1 3.9 4.9 7.6 8.6

1 First 60 days of lactation

2 The same animals in both systems


31. PERFORMANCE OF THE HOLSTEIN BREED IN TROPICAL AREAS OFVENEZUELA; J Combellas and N Martinez: Instituto de Producción Animal,Facultad de Agronomía, Universidad Central de Venezuela, Maracay

The productive and reproductive parameters of speclalized milk breeds in the tropicsare inferior to those obtained in temperate climates, The expression of geneticpotential is related with the system of production that is used. Results obtained inVenezuela for animals in confinement fed cut forage and concentrate supplementsindicate that such diets are probably limiting in quality and quantity. The high levels ofconcentrates which are required makes this system uneconomical in Venezuela andmany other tropical countries as it increases the dependence on imported cerealgrains, Systems based on intensive grazing require low levels of supplementation,however the incidence of climatic factors particularly in the wet season have animportant effect on the performance of the animals. In more extensive systems withlow levels of concentrate the response of these breeds is notably reduced. The use ofspecialized dairy breeds in crossing systems with animals adapted to the tropics is aviable alternative widely used by livestock farmers in Latin America. The lowproportion of genes from European breeds in the population appears to be determinedby social-economic conditions particular to each region.

32. PRODUCTION AND REPRODUCTION PARAMETERS OF TROPICAL SHEEP INIMPROVED PRODUCTION SYSTEMS: Josefina B de Combellas; Instituto deProducción Animal, Facultad de Agronomía, Universidad Central de Venezuela,Maracay

Approximately 20% of the world sheep population is found in tropical and sub-tropicalregions formed in general by tropical breeds and characterized by having a hair coat ,rusticity and good adaptation to the environmental conditions. They are managedusually for production of meat and to a lesser degree for hides, milk and fertilizer. Thepublished information on their performance is scarce, indicating that they have a lowergenetic potential than breeds from temperate regions especially for productive andreproductive characteristics. The average values found in improved productionsystems are 2.8 kg birth weight, 115 g/d of liveweight gain, 630 g/d milk productionand 1.2 lambs/parturition. These parameters can be improved, by crossing withtemperate breeds when management and feeding conditions justify this approach.


Pig and Poultry

33. ESTABLISHMENT OF A HERD OF YUCATECAN HAIRLESS PIGS: J L Romano,R Gomez, A Robles and L Martinez, INIP, Tizimin, Yucatan, Mexico

Data were collected over three years during the establishment of a herd of theindigenous Yucatecan hairless pig at the Experimental Centre of INIP - SARH inTizimin, Average age at puberty of females was 169 days with an average weight of19.0 kg. Age and weight at first service were 183 days and 19.3 kg. Reproductive datarelating to the 1st, 2nd and 3rd, 4th and 5th farrowing respectively were: weight atconception 24.1, 44.9, 42.9, 42.2 and 64.4 kg respectively. Weight before farrowing52.0, 68.3, 68.1, 74.7 and 98.5 kg; weight after farrowing 46.7, 61.5, 61.0, 65,5 and92.5 kg; number of piglets per litter 4.2, 6.3, 7.8, 8.6 and 8.5 ; weight of litter 4.2, 5.9,7.4, 7.6 and 8.4 kg; number of pigs weaned per litter 2.7, 4.7, 6.2, 6.5 and 6.0; litterweight at weaning 53.3 55,5, 64.8, 69.9 and 81.3 kg.

34. PERFORMANCE OF GROWING FINISHING PIGS FED WITH DIFFERENTLEVELS OF GREEN BANANAS (M sapientum) AND MOLASSES: J M Zuleta andH Losada, Colegio Superior de Agricultura Tropical, H Cardenas, Tabasco, Mexico

Thirty five crossbred pigs of average weight 30.0 kg were allocated to thefollowing treatments: A) Sorghum-based control diet; B - E) Proportions of banana:molasses of 100:0, 90:10, 75:25 and 60:40. The bananas and molasses were mixedbefore feeding and were offered ad libitum. All animals except those on treatment Aalso received in separate feeders, a 40% crude protein supplement based on fishmeal and soyabean meal fed so as ta meet the animals protein requirements. Wastegreen bananas were used and the molasses averaged 80!Brix. The experimentfinished when the animals reaches an average weight of 88 kg. Food consumptionincreased as the proportion of molasses increased. Performance was poorest (P <.05)on the 100:0 and 90:lO banana/molasses diets.

SorghumBanana :molasses

100 : 0 90 : 10 75 : 25 60 : 40

Weight gain, g/d 623 468 532 598 625


34. PERFORMANCE OF FATTENING PIGS FED DIFFERENT PROPORTIONS OFMOLASSES AND SUGAR CANE: J M Zuleta and R Alderete, Colegio Superior deAgricultura Tropical, H Cardenas, Tabasco, Mexico

Twenty eight crossbred castrate pigs of average weight 61 kg were distributed toratios of sugar cane:molasses of 0:100, 10:90, 20:80 and 40:60. The sugar cane waschopped 24 hr before being fed and treated with NaOH (4% of cane DM) to preventfermentation. The molasses was mixed with the cane immediately before feeding andthe mixtures fed ad libitum. A 40% protein supplement was fed at a level of 1.0 kgdaily, immediately before giving the basal mixture. The experiment ended when theanimals. reached an average weight of 99.0 kg. The results are given in the Table.

% DM

Cane stalk 0 10 20 40

Molasses 100 90 80 60

Live weight gain, g/d 661 549 471 465

DM intake, kg/d 3.97 3.80 3.47 3.06

35. EFFECT OF SIRE ON LITTER SIZE, INDIVIDUAL PIGLET AND LITTER WEIGHTIN A COMMERCIAL HERD: J C Segura and J M Zuleta, Colegio Superior deAgricultura Tropical, Cardenas, Tabasco, Mexico

Data from 220 piglets born in 1975 were analysed to determine the effect of paternalbreed (Yorkshire, Hampshire, Duroc) and boar within breed on live births (LB);averageindividual weights (IW) and total litter weight at birth (LW). Average values were 8.5 ±2.2, 1.41 ± 0.23 and 11.9 ± 3.3 respectively. Heritability indices (h2) and genetic,environmental and phenotypic correlations between pairs of variables were calculated.There was no effect of breed on the variables studied, but there was an effect of sireon IW and LW. Heritability values were; 0.18 ± 0.17, 0.33 ± 0.23 and 0.56 ± 0.32 forLB, IW and LW respective!,. The values for genetic environmental and phenotypiccorrelations for LB with LW and IW with LW were -0.01 and 0.012, -0.014 and 0.145,-0.059 and 0.334 respectively. Genetic improvement can be obtained by selectingindividuals irrespective of breed.

36. OBSERVATIONS ON THE EFFECT OF LEUCAENA MEAL FOR LAYING HENSAND BROILERS: J L Bastarrachea, E Laviada, M Lopez, C Echazarreta, C Francoand R Godoy, Facultad de Medicina Veterinaria y Zootecnia, Universidad de Yucatn, Merida, Yucatan, Mexico

Two experiments were carried out. In the first, 48 Babock laying hens weredistributed to 4 treatments with 3 replications in a randomised block design. Levels of0, 3.5, 5.5 and 7.5% leucaena meal were incorporated into the diet. Food intakeincreased as the level of leucaena increased, being respectively 95.3 , 94.9, 98.4 and102.1 g/d (SE ±2.99). Yolk colour was greatly increased with leucaena inclusion. Yolk


colours on the Roche colour fan scale being respectively 0, 4 - 5, 6, 7 - 8. No toxiceffects of mimosine were noticed. In the second experiment 40, 5 week old broilerswere used in 8 pens each of 5 birds. Four treatments were imposed using four levelsof leucaena meal added to a commercial diet plus 10% molasses (0, 7.5, 10 and12.5%). After 3 weeks on experiment. the weight gains were respectively .927, .916,.907 .922 kg and food conversion (feed/gain) 2.4, 2.5, 2.5 and 2.7, for the treatments0, 7.5, 10 and 12.5% leucaena meal respectively.

38. EFFECT OF DIFFERENT PROTEIN LEVELS ON BROILERS FED BANANAMEAL (Musa Sapientum): S MartInez, H Losada y R Alderete; Colegio deAgricultura Tropical, H Cardenas, Tabasco, Mexico

150 three-week old Vantress broilers of average weight 0.520 kg were distributed tothe following treatments: A) Control; B) 17X protein; C) 20X protein D) 23% protein; E)26% protein. The diets were made iso-energetic using beef tallow and were based ona 70:30 banana meal: sorghum mixture. There were varying levels of inclusion of fishmeal and soyabean meal. The control diet contained 20% protein and was based onsorghum, fish meal and soyabean meal. During the first 3 weeks the birds were fed adiet with 23% protein based on maize, fish meal and soyabean meal. The birds werekept in 15 concrete floored pens using sorghum hulls as litter. Feed and water wereoffered ad libitum. The experiment lasted 9 weeks. The results are shown in the Table.

Control

% Protein

17 20 23 26

Weight gain, kg 1.469 1.267 1.394 1.419 1.316 NS

Food intake, kg/d 4.08 4.65 4.38 3.10 3.07 P<.01

Conversion, 2.81 3.67 3.14 2.20 2.34 P<.05

Biogas

39. PRACTICAL EXPERIENCE OF BIOGAS PRODUCTION IN THE DOMINICANREPUBLIC1: R Silvestre and B Pound2 CEDIPCA, CEAGANA, Apartado 1256,Santo Domingo, Dominican Republic

Electricity consumption in the Dominican Republic has trebled over the last ten yearsand now stands at over 2000 million KWh/year. However 50% of the population live inthe rural areas and an estimated 80% of these are without access to centralizedelectricity supplies. Biogas represents an attractive decentralized alternative.


This paper describes the 5 types of anaerobic digesters which are being studied in theDominican Republic, their design features and their problems. The use of the biogasfrom the 90 m3 digester at CEAGANA in apparatus such as domestic cookers, lampsand Kjeldahl Nitrogen analysis equipment is described. Table 1 shows theconsumption of unscrubbed biogas in a dual fuel compression ignition biogasmotor/electric generator. At a constant load of 2.5 KW the saving in diesel fuel was91.7%.

Table 7 :Biogas and diesel consumption of dual-fuel generator

Operation Fuel No Load 2.5 KW Load

Diesel only Diesel 0.65 litres/hr 1.2 litres/hr

Diesel/Biogas Diesel 0.6 litres/hr 0.1 litres/hr

Biogas 1.6 m3 /h 3.3 m3 /h

1 The support is acknowledged of the Projects OAS (Fondo Mar del Plata) and FAO/UNDP DOM/77/002

2 Technical Cooperation Officer ODA Great Britain

40. THE EFFECT ON BIOGAS PRODUCTION OF ADDING PRESSED SUGARCANE STALK AND UREA TO CATTLE SLURRY1: B Pound2 and Fausto Done,CEDIPCA, CEAGANA, Apartado 1256, Sto Domingo, R.D.

Eight laboratory batch digesters (flasks of 2 litres capacity) were used in trial toinvestigate the effect on biogas production of adding pressed sugar cane stalk andurea to cattle slurry. the treatments were 0, 26.6%, 53.3% and 80%(of DM) pressedcane stalk in the digesta mixture and 0 and 2% of N as urea (% of stalk DM). Thesetreatments were arranged in a 4 x 2 factorial without replication. The treatments werecalculated to give a constant C:N ratio in the urea treatments. Slurry of 25 days of agewas used as innoculant in all the digesters (20% on a DM basis). The balance of thedigester was fresh slurry (faeces and urine) from cattle receiving sugar cane diets. Alltreatments had a total solids content of 8%. Table 1 shows the effects of treatments on pH. The urea treatments were consistentlyhigher and the addition of increasing amounts of cane stalk decreased the pH to a lowlevel. Figure 1 shows the difference between the control and the 26.6% level of cane

Table 1:Effect of treatment on pH

% of Stalk With urea Without urea

0 6.97 7.04

26.6 6.39 5.23

53.3 4.93 4.33

80.0 4.34 3.92


stalk for the treatments with and without urea. Higher levels of cane stalk wereassociated with even lower yields of gas. The indications from these preliminary data(first eighteen days of the 40 day trial) are that the pH is too low on the treatmentswithout urea for the methanogenic bacteria to operate successfully. On the ureatreatments only the low level of stalk was associated with a pH value sufficiently highto allow reasonable gas production. It is proposed to repeat the experiment with lowlevels of stalk using lime to buffer the system.

Figure 1:Additive production of biogas

1 The support of of the project FAO/UNDP DOM/77/002 is recognised

2 Technical Cooperation Officer, ODA, UK

abstracts university of yucatan, mexico merida …seen as flexible and versatile crops for the...

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