Franklin Vets are able to assist in determining your bull’s soundness and fertility to ensure that bull performance is not the limiting factor on your farm. We can advise you on the following areas:
Do not assume you have enough bulls for the likely number of empty cows at the end of artificial breeding. Follow the advice on the table below.
Careful bull selection can reduce the risks of selecting subfertile bulls however, it is better to test them to save costs should they not perform. The exam we offer checks
- Palpitation and measurement of testicles
- Palpitation of internal sex glands
- Collection of semen and examination of the penis
- Examination on farm for motility
- Examination of semen in the lab for morphology.
We can assess the overall appearance of bulls for deformities, body weight conditions, aggressiveness, and legs and claws for walking.
If bulls are not correctly managed, fertility can crash, just like cows that are poorly managed after calving,
BVD is easily spread among the herd and can have devastating effects. Ensure that all bulls are blood tested before they join the cows. Bulls should also receive two shots of BVD before they are mixed with the herd or heifers.
It is important to plan ahead and ensure that you have enough sound mating and healthy bulls on the farm well ahead of mating. Talk to your Franklin Vets team for advice and to find out more about Dairy NZ InCalf bull selection tool.
The table below shows the number of bulls required based on herd/mob size and expected number pregnant at the end of AB. If you are unsure of a likely number pregnant at the end of AB, give us a call and we can discuss based on AB length, submission rate, calving spread and cow condition.
|No cows in||Likely % of herd pregnant at start of bull mating|
|milking herd||very low||low||moderate||high|
|100||2 to 4||2 to 3||2||2|
|200||5 to 6||4 to 5||2 to 3||2|
|300||7 to 8||4 to 5||3|
|400||9 to 11||7 to 8||5 to 6||3 to 4|
|500||12 to 13||9 to 10||7||4 to 5|
The numbers stated are for bulls in with the herd on a daily basis. Dairy NZ suggests you should have the same number resting, with bulls doing two days on, two days off, to maintain body weight, feet and libido.