Reason Behind Infertility in Cow Full Lecture
(Roberts, 1956) said that Cattle are deemed infertile when they are neither normally fertile nor completely sterile. Interest in bovine infertility increased with the introduction of artificial insemination in the 1950s and as the factors involved became known to farmers, herdsmen physiologists and other workers.
The causes of infertility are many and can be complex (Arthur, 1982). They relate to Graafian follicle development and maturation, oestrus onset, successful coitus, ovulation, fertilization, implantation, and the development and delivery of the foetus and its membranes. Anything interfering with these routines, such as diseases, poor nutrition, inadequate herd management, hereditary and congenital factors, hormonal disturbances or environmental changes, makes the animal infertile, if only temporarily (Osmanu, 1979).
Ten to 30% of lactations may be affected by infertility and reproductive disorders (Erb and Martin, 1980), and 3-6% of the herd is culled annually in developed countries for these reasons. The extent of the problem is likely to be similar in the tropics, although extensive data are not available. In Zambia, for example, the National Council for Scientific Research (NCSR, 1970) noted that infertility is one of the major problems confronting the cattle industry, but that the extent and causes were still obscure. Although it was believed that up to 40% of local cattle were infertile, no systematic studies had been undertaken at that time. Details are given below of some of the common causes of infertility.