Abstract
Efficiency of sheep production is conditioned by fertility. According to some authors number of offspring obtained per lambing is more important than gain of weight. Genetic relationships involving reproductive traits were seldom studied. Reproductive traits have low heritabilities, a discrete phenotypic expression, and are expressed only in sexually mature ewes leading to low selection intensities and long generation intervals. Documentation of realized selection response is also often complicated by the low heritabilities of fertility traits. Existence of a major gene affecting prolificacy had been suggested and at that time there were many sceptics who strongly doubted that a trait as complex as reproduction could be profoundly influenced by a single gene. Major genes affecting prolificacy in sheep was founded. A mutation in the bone morphogenetic protein 15 gene (BMP15, also known as GDF9B) responsible for high prolificacy in Inverdale sheep had been discovered and evidence of segregating major genes was being reported from flocks around the world. Development of gene mapping techniques, and locating alleles that are responsible for the fertility of sheep began a new chapter in predicting and controlling the fertility of sheep. The beneficial effects of nutrition on reproduction in sheep are well known. This procedure is known as flushing. The effect of Body Condition Score (BCS), before mating, during mating and after mating period, on reproductive efficiency of different breeds of sheep in the different rearing systems were studied. The farm manager has the ability to control or at least to manipulate the factors that have an impact on fertility.
Highlights
Fertility is one of the most important parameters of sheep productivity, the number of offspring obtained per lambing is a good indicator, and according to some authors (Petrović, 2000) it is more important than gain of lambs
Based on the results presented by various authors, it could be concluded that the fertility of sheep is very complex property, and because of its importance in achieving success in sheep production, it has been studied from various aspects
Major genes affecting fertility have been found in many sheep around the world
Summary
Fertility is one of the most important parameters of sheep productivity, the number of offspring obtained per lambing is a good indicator, and according to. Some authors (Petrović, 2000) it is more important than gain of lambs This means that biological efficiency of sheep in regard to meat, milk and wool production is conditioned by fertility ( Notter et al, 2000). Lassoued et al (2004), showed important interactions between genotype and level of nutrition In this sense, in highly prolific ewes like D’Man breed, higher levels of nutrition prior to and during mating were associated with improved reproductive performance, but in low prolific breeds such as Queue Fine de l'Ouest, neither ovulation rate nor lambing rate were affected by the dietary treatment. It is linked to many as genetic and external factors (Petrović, 2000) Very often it is associated with climatic and seasonal conditions over which the producer has little control. In this paper we would like to touch about the following factors that may affect the fertility of sheep:
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
