What are your fertility goals?
The fertility goals for seasonal herds have traditionally focused on the empty rate with some consideration given to late cows. The final empty rate is the result of a process of several steps and each step has a goal to be met.
A slow start to mating cannot be fully compensated for by the bulls so the overall goals should therefore be twofold:
- 6 week in-calf rate 78%
- Final Empty rate 12 week mating - 8%; 10 week mating - 10%
The drivers of the 6 week in-calf rate are the 3-week submission rate (target 90%) and conception rate (60%). Success in meeting these targets is determined by how the herd performs in the following areas:
- Calving pattern 60% by 3 weeks; 87% by 6 weeks; 90% by 9 weeks
- Non-cycling cows 15% at the planned start of mating (PSM)
- Heat detection 95% of early calved mature cows by 3 weeks
Calving pattern
Calving pattern is determined by the previous mating so cannot be influenced before the PSM except by inducing. The calving pattern is an early warning of anticipated submission rate that is likely to be encountered at mating. If behind target on calving pattern, a concerted effort at mating will be necessary to make a difference. A condensed calving pattern is a medium to longer term goal that requires improvements in all aspects of mating management.
Avoiding non-cycling cows
The resumption of cycling is determined by the time since calving and body condition score (BCS). Later calving cows have less time available to them, so calving date is important to the individual cow and calving pattern to the herd overall. Weight loss after calving is unavoidable so the aim here is twofold. One is to have the cows calve with a BCS of 5.0-5.5 to give them a better starting point. Two is to minimise weight loss in early lactation. Weight loss that exceeds 1 BCS is associated with longer non-cycling periods.
It is only possible for cows to gain 0.5-1.0 BCS in the dry period so cows need to be at least 4.0 at drying off to have any chance of making up the deficit. This gain needs to happen earlier in the dry period before the final month of pregnancy. Overweight and light cows are more likely to be non-cycling by PSM. If either of these groups exceeds 15%, the herd's overall performance will be affected. There is an opportunity to direct feed from those that don't need it to those that do.
Heat detection
A good indicator of heat detection efficiency is the number of mature cows (> 4 years) that calved at least 8 weeks before the PSM and were submitted in the first 3 weeks of mating. The Fertility Focus report available on MINDApro calculates this for each herd and experience to date is that heat detection is an area that is not up to target. The target is 95% with intervention recommended below 90%. Heat detection needs to be given the highest priority in the daily work schedule over mating.
These goals are an overview and a more detailed discussion is required at an individual herd level. In practice, most herds are not meeting these goals yet. Each herd will be at a different starting point so initial goals will be different in each case. The InCalf programme is a guide for vets and farmers to benchmark herds and then to develop and work through a plan for improving reproductive outcomes.
Totally Vets anticipates that the InCalf programme will make a difference on your farm no matter where your herd's reproductive performance currently stands.
