A good idea or a load of bull?!
As our Spring calving herds have commenced calving (dairy nearly finished, beef mid season), now is the time to think about ensuring you have adequate bull power for the breeding season ahead.
A fully “fertile” bull is defined as ‘a bull that can get 45 out of 50 cows in calf in 90 days (i.e 90% in 3 cycles)’, 60% of these cows should get in calf to the first service and should therefore calve in the first 21 days of the calving period.
It is estimated that one in three bulls fall into the sub fertile (can achieve a pregnancy but not at the rate achieved by fertile bulls) or infertile (bulls that are incapable of reproducing) category.
Signs of reduced bull fertility include:
- Prolonged calving period
A compact calving period will deliver:
More weight of calf per cow mated.
More efficient use of labour
Calves of uniform size
Cows at a similar stage in the production cycle.
A prolonged calving period can increase the number of calves born, however these animals are younger and hence lighter at weaning. Early calves are the most profitable in the beef herd and early calves in the dairy herd allow cows to milk for longer if you have a fixed dry off date.
2) Increased numbers of barren cows.
A realistic target is 95 calves/100 cows/year.
3) Delayed calving to conception.
Delayed calving results in lost dairy production and reduced numbers of replacements.
A BBSE can give an indication as to how many cows are likely to be successfully covered by a bull, thus enabling a judgement to be made on the likely ‘bull power’ needed prior to the service period.
A BBSE is a useful tool in the marketing and subsequent sale of bulls.
How long before the breeding window should bulls be tested?
Bulls should be tested at least 60 days before the service period. This is because the production and maturation of sperm takes two months. If necessary this time lag enables other arrangements to be made.
Don’t delay, book your BBSE today to identify problem bulls and have a more profitable calving season.
