Spring is now here (at last!) and calving and lambing are in full swing. They are perhaps even busier than usual because of the challenges of delivering the deformed monsters that Schmallenberg infection earlier in pregnancy has left us with. (On a positive note, immunity following infection with the Schmallenberg virus is predicted to be solid and long-lasting, so that animals that have given birth to affected calves and lambs this year should not suffer similar problems for several years to come.)
Despite time pressures, bull fertility for the coming serving period should be being considered now. While a full BBSE (Bull Breeding Soundness Examination) carried out by one of our vets might be considered ‘gold standard’, attention should be paid to body condition, locomotion and the bull’s reproductive apparatus, even if one is not carried out.
Breeding bulls should be ‘fit, not fat’. If they are too thin sperm quality will be poor and they will lack the stamina to work effectively for the entirety of the serving period. If they are too fat, they may be lazy and a layer of fat within the scrotum surrounding the testicles will compromise sperm production.
If the bull cannot walk freely and easily, he may not be able to get to and then mount bulling cows. Conformation should be assessed; hind legs that are too straight are just as bad as those that are too bent, and any lameness issues or over-grown claws should be given attention now to allow time for recovery before you expect the bull to work. I suggest one of our foot trimmers visit, to inspect and, if necessary, trim all you bulls feet. Feeding additional biotin and zinc can be useful to promote good horn growth (although the benefits of this will not be seen for several months after starting supplementation, so starting now is arguably too late!).
Inspection of the prepuce to ensure the absence of any nasty discharges, palpation of the penis to make sure no abnormal swellings are present and palpation of the scrotum and testicles are all essential. Both testicles must be present and should be the same size (approximately) and consistency; this is firm but not hard – a ripe melon, a flexed bicep or a new tennis ball (take your pick!)- with no herniation of abdominal contents into the neck of the scrotum. Picking up on these issues could prevent poor performance during the serving period and a nasty surprise at PDing or, even worse, next year’s calving.
Even if all this – or even a full BBSE – is done, this is not the end of the matter. It doesn’t matter how good the bull’s semen is, if he can’t identify a bulling cow, get to her, mount her, achieve intromission and ejaculate, then pregnancies will be few and far between. Continued monitoring of bull performance and female return rates during the serving period continues to be important, to reassure that all is progressing as planned but also to provide an early warning if it is not, so something can be done about it.
Written By Keith Cutler, Veterinary Surgeon
