Twinning in cattle.
نویسندگان
چکیده
INTRODUCTION The biological efficiency of traditional systems of beef production is low due to the low reproductive rate and the high proportion of total energy which is required for maintenance of the breeding herd. Dickerson (1978) estimated that 56% of the total feed energy intake for adult and market cattle is required solely for body maintenance (the non-productive energy requirement rises to 73% when replacements are considered). He also estimated that increasing reproductive rate from 0.8 to 1.8 could reduce the feed energy required by 25% per kg of edible meat protein. Preliminary experimental results from embryo transfer (Dickerson et al. 1988) and genetic studies (Gregory et al. 1990) show that gains of this order seem possible. The Meat Research Corporation (MRC) has sponsored a co-ordinated project on the application of advanced reproductive technology in temperate zone cattle which has focussed on beef twinning. While twinning has been the subject of a number of reviews (e.g. Hendy and Bowman 1970, Gordon 1983 and Morris 1984), the major stimuli for the current project were the finding that immunisation with ovarian follicular fluid (Cummins et al. 1986) and purified inhibin (Bindon et al. 1988) could stimulate multiple ovulation in cattle and from the development (Lu et al. 1987) and cornmercialisation of in vitro fertilisation and embryo transfer to induce twinning by Ovamass Ltd in Ireland. Alternative pathways to twinning are shown in Fig. 1.
منابع مشابه
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عنوان ژورنال:
- The Veterinary record
دوره 88 8 شماره
صفحات -
تاریخ انتشار 1969