In a commercial suckler herd, smaller cows weaned calves that were as heavy as calves from bigger cows and in doing so proved to have greater efficiency of production.
Phil Jones at Lan Farm, Cynwyl Elfed, Carmarthen has been monitoring cow and calf weights at weaning for his 100 cow herd for the last five years, alongside using AI to breed replacement females for the herd. Choice of sire has concentrated on sourcing black Limousin bulls with top 25% EBV values for maternal traits, including maternal calving ease and direct calving ease, and top 10% for 400 day growth. The aim is to produce a cow that will rear a calf with a 200 day weight at 50% of the cow weight.
Results of monitoring since 2012 show:
- Older cow weights have increased by an average of 70kg to 675kg
- Older cows have consistently weaned calves at 51.3% of cow weight
- Body Condition Scores for the 10 lightest cows tend to be 0.4 to 1.0 score lower than for the 10 heaviest cows at weaning
In 2016:
- Adjusted to 200 days to compensate for calving spread, cow efficiency averaged 40% for older cows and 39% for first calves
- By weight bands, the most efficient cows in the herd were those under 650kg weaning calves that weighed 51% of cow weight
- Cows weighing over 700kg weaned calves of 40% of cow weightHeifers at Lan Farm were calved at two year old for the first time in spring 2016 allowing a direct comparison with three year olds calving in the same season:
- Two-year-old heifers weighed 542kg at weaning and three year old heifers 623kg
- There was hardly any difference in daily gains to weaning for the two groups of calves
- Heifers calving at two-year-old returned an efficiency of 41% and three-year-old heifers 36.1% when adjusted to 200 days
Key messages:
- The optimum suckler cow weight at Lan Farm is 550-650kg
- Savings in maintenance cost between keeping a 780kg versus a 500kg cow amount to £73 per annum or £600 over an 8 year life
- Breeding decisions may need to focus on choosing maternal bulls with medium 400 day growth figures
- Heifers calving at two year old have reared calves that grow as well as calves from three-year-old calving heifers
- Calving heifers at two year old increases herd output by producing an extra calf and may help to check the steady increase in cow mature size
- Management according to condition score at weaning is vital to ensure that fertility related issues do not emerge in future