The heat is on as the breeding season kicks in
We are now between three and six weeks into our spring calving breeding programme and the challenges of heat detection and AI are indeed immense.
As herd size increases, the cost of accurate heat detection is a job in itself. Note, the descriptor 'accurate'. Many farmers in their pursuit of high admission rates and the €250 cost of a missed heat, are submitting cows for AI which are not in heat.
As you complete your first three weeks of breeding, it is essential to identify those cows which have not been bred. These should be presented for veterinary attention as there is a €250 reward for every breeding opportunity accurately detected. The same rule applies when using a stock bull. One in 10 stock bulls will be either subfertile or infertile. Have you had your stock bull fertility tested? It is also essential that you can identify problem cows using tail paint, which is topped up at least twice a week.
There is a temptation to 'blindly' administrator prostaglandins to those cows not detected in heat. This will only work if cows are reproductively sound and in the middle of their cycle.
Some cows may respond to prostaglandins but the heats will be infertile as there is a uterine infection preventing the normal expression of heat.
The sensible approach is to seek veterinary attention bearing in mind the costs associated with failure to successfully breed the cow at the right time.
When stock bulls are run with the herd, there is a significantly greater risk that cows with reproductive problems will not be identified. Stock bulls will address poor heat detection if the cows are fit and cycling. As stressors in the herd increase, reproductive dysfunction increases with poorer manifestation of heats. It is important to have sufficient bull power when using stock bulls. You need one fit bull for every 40 eligible cows.
It makes economic sense to scan your herd, when running stock bulls six weeks into the breeding programme. This will enable veterinary attention for cows with reproductive problems. This will account for 10-15pc of your cows with a minimum opportunity cost of €5,000 for reproductive failure in a 100 cow dairy herd.