Yearling heifer mating Rebecca 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 ReasonImportant or very important Increased profit80% Shorter unproductive period of heifers78% More calves per cow over her lifetime66% Increased rate of genetic gain50% Earlier selection of replacements40% Reduces mature size (maintenance) of heifers28%

Why NOT calve heifers? ReasonImportant or very important Concerned about rebreeding of 2yo heifers60% Need mob (empty R2 heifers) that can be fed less when required 51% Stunting of heifers mature size49% High dystocia in 2yo heifers37% Requires different management skills37% Want a higher pregnancy rate than could be achieved at 15 months 37% Returns do not justify the extra costs23%

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 LinePost-partum anoestrus interval (days) Pregnancy rate to second joining Angus10191% Angus x Friesian9796% Angus x Jersey90100%

Try it! But choose your bull wisely Thanks to Beef + Lamb NZ for funding the research underpinning this talk