Pregnancy rates in cattle herds vary from very good to very bad. Some of the poorest results are achieved when bulls fail and pregnancy rates can drop well below 50% for any given joining period. To help avoid this scenario, the bull breeding soundness evaluation was first devised over 60 years ago. Today, with the benefit of improved knowledge and technology, the Veterinary Bull Breeding Soundness Evaluation (VBBSE) represents the best insurance available against bull infertility.  

What is a VBBSE?

The VBBSE is a relatively quick and economical procedure ($70-100/bull) for screening bulls prior to sale or use. The Australian Cattle Veterinarians (ACV) have developed world recognized procedures and standards for conducting VBBSEs and for computerising the relevant information.

What does it involve?

Usually, the following procedures are followed:

1. A general physical examination
2. A reproductive examination (including measurement of testicle size or scrotal circumference).
3. Collection and examination of semen (particularly for sperm motility and morphology).

In addition, a libido/serving capacity test may be included, as may special tests for diseases (e.g. vibriosis or trichomonosis). Although these procedures add predictive value to the VBBSE and may be indicated in some situations, they are not mandatory.

Following these tests, bulls are placed into the following categories;

  Satisfactory: All factors assessed were consistent with ACV standards. No risk factors for reduced fertility identified.

  Unsatisfactory: Some factors assessed were not consistent with ACV standards. E.g. Lameness, penile injury or semen morphology defects.

  Classification Deferred: Although not all factors met ACV standards, this probably would not preclude using the bull under certain conditions. E.g. Mild post-leg – likely to develop arthritis prematurely.

  Not tested: Factor(s) could not be adequately evaluated. A retest is often recommended.

In Summary

Where natural breeding bulls are employed, the VBBSE should be an integral management tool for optimising herd fertility, genetics and profitability. If done pre-joining, 1-3 months prior to the joining is ideal.

When your mare goes into labour it is a good idea to supervise her, but refrain from disturbing the process unless you become concerned. Ideally checks are performed every ½ hour - this includes during the night, as this is when most mares foal.

Stage 1 – Your mare will be preparing the foal for delivery. She will be up and down as the foal makes its way into the birth canal. This may go on for several hours and ends when her water breaks.

Call us if:

• You see a red membrane coming.
• The mare is straining but nothing appears.

Stage 2 – Foals come feet first followed by the head. Both feet appear within the white membrane, soon followed by the head. Take note of the time you first see the foal’s legs appearing. Watch the rest of the foaling from this point, which should be complete within 30 minutes. The white membrane covering the foal normally ruptures of its own accord, however if it does not you must manually rupture it so that the foal can breathe. Apart from this, you should just observe the pair without interference, allowing them to bond. Record the time the foal is delivered.

Call us if:

• Only 1 leg appears, or a head is coming without any legs visible.
• The foal is not out within half an hour.

Stage 3 – The delivery of the placenta. This normally occurs 1-4 hours after the birth. It can help if you are able to tie it into a ball to prevent it flapping around the mare’s hocks and scaring her. It will then come away under its own weight. Once the placenta drops you should check it to make sure it only has one hole.

Call us if:

• The placenta has not passed within 4 hours.
• The mare appears to have colic after the foaling.
• You think there is breaking or tearing of the placenta.

The behaviour of a healthy foal immediately after foaling is quite predictable. They are generally thirsty for a drink of colostrum, and are able to stand very soon after birth. It is important that you make a timeline of the following events of the foal. An example of a table which may help you is:

Colostrum

Foals are born without any antibodies in their blood. They acquire it all from the mare’s colostrum (first milk). The IgG level assessment is to make sure the foal has received enough colostrum to give it immunity in the first few months of life. If the foal doesn’t suckle enough colostrum or the colostrum quality is low, it may not acquire adequate immunity to fend off any bugs it encounters. Subsequently it will much more susceptible to illness. If this is the case, we can intervene by supplementing more colostrum or providing the foal with immunity via plasma transfusions.

Vet check

We recommend all mares and foals are vet checked within 24 hours of birth. Early disease detection in both mare and foal can be lifesaving.