Yearling heifer matingRebecca Hickson

• Profitability of calving heifers• Beef cow efficiency• Why calve heifers• Why not calve heifers• Performance of heifers in industry• How to calve heifers

Outline

• The 2-year-olds will be there anyway– How much extra has it cost you to feed them to support

pregnancy and lactation?

• More calves = more income from the beef herd– What is an extra calf worth?

The costs and the income

– Assume heifers are 346 kg at 15 months (joining), 484 kg at 31 months (weaning)

– Calves are 34 kg at birth, 232 kg at weaning at 208 days of age; 6 kg milk/day

– Pasture is 11 MJ ME per kg DM

• Non pregnant heifer eats 2565 kg DM• Heifer and calf eat 3713 kg DM • An extra 1149 kg DM (45%) over empty heifer

• At 12c/kg DM this is an extra $138 in feed eaten

Example of extra costs

Example of extra income

232 kg weaner at $2.20/kg = $510??

• Beef cows are exceptionally inefficient– 70% of feed requirements are for maintenance

• Efficiency depends on– Number of calves weaned– Weight of calves weaned– Feed requirements (live weight) of cows

Efficiency (or lack of it)

• Smaller cows – breed and EBVs• Bigger calves – breed and EBVs, ‘milky’ cows

• More calves– National calving percentage hardly changed in 20 years – Getting calves from the 2-year-old heifers increases number of

calves far more than any tweaking of calving percentage of mature cows

Increasing efficiency

Why calve 2-year-olds?Survey of 331 farmers in charge of 16,000 heifers

Reason Important or very important

Increased profit 80%

Shorter unproductive period of heifers 78%

More calves per cow over her lifetime 66%

Increased rate of genetic gain 50%

Earlier selection of replacements 40%

Reduces mature size (maintenance) of heifers 28%

Why NOT calve heifers?

Reason Important or very important

Concerned about rebreeding of 2yo heifers 60%

Need mob (empty R2 heifers) that can be fed less when required

51%

Stunting of heifers mature size 49%

High dystocia in 2yo heifers 37%

Requires different management skills 37%

Want a higher pregnancy rate than could be achieved at 15 months

37%

Returns do not justify the extra costs 23%

• Based on a simulated farm with a fixed feed supply, and assuming an assisted birth killed 36% of calves and 11% of heifers…

• More profitable to calve 2yo heifers than 3yo heifers as long as incidence of assistance remained below 89%

Simulated profitability and dystocia

• 86% pregnant per heifer joined• 78% calves marked per heifer joined• 9.6% heifers assisted at calving

– Of 386 assisted births:• 36% of calves died • 11% of heifers died

• 84% of heifers that calved at 2 calved again at 3– 7% were empty, 9% culled for other reasons or died

Industry performance of 2yo heifers

• Well grown– Reach puberty (mean live weight 297 kg for Angus heifers)– Get a ‘head start’ on the calf – reduce dystocia

Get heifers ready for joining

• All about the EBVs!– Direct calving ease (higher is better)– Birth weight – Accuracy: is birth weight measured in the herd you are buying

from? Do they calve their 2 year olds?

• Shape is of little (no?) importance, just birth weight

• Daughters’ calving ease EBV useful if choosing a bull to father your replacements

Choosing the right bulls

• Feeding in early pregnancy does not affect dystocia– Losing 560 g/d from 6-12w of gestation reduced milk production

• Feeding in late pregnancy does not affect dystocia reliably– Underfeeding can reduce milk yield, calf weight and pregnancy

rate to rebreeding

• Keep them within the range of ‘normal’, neither very thin or very fat

Feeding during pregnancy

• Where do you calve them? • How often do you observe them?• At what point do you assist?

Management at calving

• Cull heifers that don’t get pregnant at 15 months• Dystocia at first calving does not imply future

dystocia• Rebreeding at 2 not a big problem (?)

Rebreeding & culling

Line Post-partum anoestrus interval (days)

Pregnancy rate to second joining

Angus 101 91%Angus x Friesian 97 96%Angus x Jersey 90 100%

Try it!But choose your bull wisely

Thanks to Beef + Lamb NZ for funding the research underpinning this talk