• Companion / Sport Animal Nutrition

• Companion / Sport Animal Housing

• Practical Animal Handling

• Management and husbandry of horses, dogs and cats.

Research interests:

• Nutritional effects on reproduction in ruminants

• Ovarian follicle and embryo quality in ruminants

Current research area:

The increase in milk yield following the introduction of substantial amounts of Holstein genetic material coupled with selective breeding strategies has been accompanied by a decrease in fertility in dairy cows. Conception rate to first service has declined rapidly since the mid seventies in both the US and UK. In Ireland it was reported that more high genetic merit cows were culled as infertile, compared with medium genetic merit cows. These high yielding cows can suffer severe metabolic stress in early lactation as they strive to meet the nutritional demands of high production. This situation is even more critical under Irish spring milk production systems, where cows are grazing relatively high protein pastures during the time of the breeding season. This may result in low fertility particularly where high levels of nitrogen fertilizer have been applied. The high rumen degradable protein content of this grass coupled with a negative energy balance results in elevated urea concentrations in the circulatory system. In order to ensure optimum fertility in high yielding dairy cows, the correct nutritional supply of both energy and protein is critical.

Publications:

O’Callaghan,D., Lozano, J.M., Fahey,J., Gath,V., Snijders,S., and Boland, M.P. (1999). Endocrine and metabolic effects of nutrition on fertility. Animal Science. In press.

Gath, V.P., Fahey.J., Snijders and O’Callaghan,D. (1999) .Effect of plasma urea concentration at the time of insemination or embryo transfer on pregnancy rate in cattle. Proc. British Society of Animal Science, Occasional meeting.

Gath, V., Lonergan, P., Boland, M.P. and O’Callaghan, D. (1999). Effects of diet type on establishment of pregnancy and embryo development in beef heifers. Theriogenology,51:1. Abst 224.

O’Kearney-Flynn. M., Wade. M., Duffy. P., Gath, V., Boland, M.P. and Dobrinsky, J.R.
( 1998 ). Effect of cryopreservation on IVP cattle embryo development in-vitro and in-vivo. Theriogenology, 49:1. Abst 173.