Dystocia or difficult calving is a condition where help is required as providing traction, repositioning of fetus, foetotomy or caesarotomy. Generally, ease of calving is very good in zebu breeds. One of the main causes of dystocia is crossbreeding wherein short statured zebu cattle are crossed with large exotic bulls – a strategy commonly employed for increasing milk production. Crossbreeding results in production of larger sized calves leading to dystocia. Large calves can also result from overfeeding late in pregnancy leading to dystocia. Generally the incidence of dystocia is higher in heifers than cows within a particular breed. Underfeeding of heifers before calving, heavy parasite load, lack of skeletal development and small pelvic area, milk fever, ketosis, foetal abnormalities are also some of the causes for dystocia. The economic importance of difficult calving lies in the high cost of obstetrical assistance in addition to deterioration of general health, lower milk production as well as subsequent infertility of the dam and high perinatal mortality.Other reproductive disorders The vulva, the vestibule, the vagina and the cervix are all involved in copulation.
Their contractile and elastic elements taken together with the production of mucus at estrus will ensure a low bacterial population in the lumen. White heifer disease is a genetic disorder caused by a recessive gene which leads to defective development of the Muellerian duct and may involve the vagina, the cervix, the uterus or all these organs together even though the ovaries are normal. The animal exhibits normal estrous cycles. The animal suffers from a hypertrophic and sclerotic hymen in the anterior- vagina behind which uterine secretions accumulate. These secretions become infected during natural or artificial inseminations as well as provoke intense abdominal straining with general illness which may prove fatal. In other types of white heifer disease, parts of the uterus are absent or isolated by a septum leading to total infertility. The responsible recessive gene can be transmitted by either parent.
Other disorders seen are vaginal prolapse with the extrusion of the vagina in an inverted state during the last trimester of pregnancy. This is also an inherited predisposition which can however, be suitably arrested by providing adequate obstetric help.