The fertility of ewes is often reduced at the first oestrus after the oestrous cycle has been synchronised, due to impaired sperm survival and transport (Quinlivan and Robinson 1969). Any reduction in fertility . can be alleviated through use of higher semen dose rates in artificial insemination programs, or through the use of a higher percentage of rams if naturally mated (Cognie and Mauleon 1983). Some studies have shown no difference in fertility between synchronised and unsynchronised ewes after artificial insen1ination (Donovan et al 2004) or when mated to rams (Godfrey et a/1997). The recommendations for one ram per 5 to 7 (Cognie and Mauleon 1983) or 10 ewes (Miller 1991) are well above the 1% rams commonly used at a natural joining. However, there is a scarcity of data defining fertility when lower percentages of ratns are naturally mated with synchronised ewes. If both fertility and the distribution of conception are adequate with fewer ratns, costs could be substantially reduced.
|Number of pages||1|
|Publication status||Published - 2012|
|Event||Joint Conference of the New Zealand and Australian Societies of Animal Production (NZASAP) - Lincoln University, Christchurch, New Zealand, New Zealand|
Duration: 02 Jul 2012 → 05 Jul 2012
|Conference||Joint Conference of the New Zealand and Australian Societies of Animal Production (NZASAP)|
|Period||02/07/12 → 05/07/12|
Robertson, S., King, B., & Friend, M. (2012). Fertility and Distribution of Foetal Age in Synchronised Ewes Mated Naturally. 56-56. Poster session presented at Joint Conference of the New Zealand and Australian Societies of Animal Production (NZASAP), New Zealand.