More than 200 experts from 24 countries around the world will gather in Westport next month for a major international conference on an issue which could be costing Irish agriculture anywhere between €100 million and €300 million annually – bull fertility.
"We have 30,000 to 40,000 bulls in the country. If just 4 per cent of them are sterile at any one time that's 1,000 to 1,500 cows with no calves," says conference chairperson, Dr Michael Diskin, who is also head of Teagasc's Animal & Grassland Research and Innovation Centre.
This is the first conference of its kind for several decades, he says. “Most of the research on bovine fertility has been on the female side. The 1940s and 1950s were the golden era for male fertility research. However, we are now at an exciting time for male reproduction research with the recent advances in the identification of infertile and sub-fertile bulls. Also, the importance of milk and beef production in this country makes it opportune that Ireland has been chosen to host the conference.”
Specific topics to be addressed at the conference include male reproductive physiology; optimising semen procedures; AI bull fertility; sperm and seminal plasma; thermoregulation and behaviour; pathophysiology of bull subfertility; bull production, selection and evaluation; and breeding soundness evaluation of bulls.
Grazing season
The bull fertility issue is exacerbated by Ireland’s grass-based production system which demands highly seasonal calving patterns immediately in advance of or at the start of the grazing season. In essence, the aim is to have all calves born in early spring. “This demands high bull fertility irrespective of whether AI or natural service is used,” says Mr Diskin.
Interestingly, data from the Irish Cattle Breeding Federation (ICBF) suggests that almost 50 per cent of the calves from dairy cows and 77 per cent of those from beef cows are produced through natural service.
“This obviously reflects the convenience of using natural service bulls and also highlights the importance of the fertility in such bulls,” Mr Diskin points out.
“However, in herds dependent on natural service bulls to get cows pregnant, it’s not simply about turning in a bull with a herd of cows and expecting calves to arrive nine months later. International data suggests that between four and five per cent of bulls are infertile at any one time with a further 20-30 per cent being classified as sub-fertile. Both conditions can have major effects on herd reproductive, productive and economic performance, particularly where these conditions go undetected for a number of weeks.”
Complexity lies at the heart of the problem, as Mr Diskin explains. Many factors can affect bull fertility and they all need to be taken into consideration. “A bull that is infertile this year may be fertile next year and vice versa,” he says.
There are also issues with the 60-day sperm production cycle. It is quite fragile at the early stages of the cycle and can be susceptible to damage if the bull has even a minor infection. “That means the bull could be sub-fertile 60 days after having a fever,” he says. “You’ve got to be aware of these things.”
Challenges
The conference affords Irish veterinarians, beef specialists and those interested in bull fertility the opportunity to join experts from across the globe to discuss the significant developments and challenges facing bull fertility, from the way genomically-assisted selection has revolutionised dairy cattle industry to reliably predicting the fertility of individual bulls in the laboratory. Specialists from academia, veterinary practice and industry will discuss topics on male reproductive physiology, nutrition, puberty, the genomics of bull fertility, the role of sexed semen, and the identification of infertility and sub-fertile bulls.
“The whole objective is to bring some of the best experts from around the world together for conference in Westport to share their knowledge on this important topic,” says Mr Diskin. “All of the presentations will be condensed into one publication afterwards and this should be of significant value to all those with an interest in cattle reproduction.”
The three-day event will kick off with a tour to a local dairy farm, followed by two days of scientific sessions featuring leading experts from around the world. The final day will be devoted to the practical aspects of breeding soundness evaluation and takes place in a nearby mart.
Organised under the auspices of the British Society of Animal Science (BSAS) with support from Teagasc, UCD, the University of Limerick and a number of other organisation, Bull Fertility – Theory to Practice takes place in the Castlecourt Hotel, Westport, Co Mayo, from May 27 - 30th.