Reproductive tract infections
The major cause of reproductive tract infections are, improper dry cow nutrition, contamination at calving due to unsanitary calving area; virulent organisms in calving area and unsanitary human interventions at calving time. Dystocia, retained placenta, infectious pathogenic micro-organisms, viz. Arcanobacterium pyogenes, Escheridia coli, mycoplasma bovigenitalium, haemophilus somnus, ureaplasma, the bovine herpes viruses, infectious bovine rhinotracheitis (IBR), infectious pustular vulvovaginitis (IPV) cause vaginal and uterine infection. Unsanitary examinations or insemination technique, over-conditioning at calving relates to a higher incidence of these infections. Low level of calcium in the diet is a contributory factor for high incidence of retained placenta, which may develop into uterine infection. Other nutrition deficiencies point to shortage of selenium and vitamins A or E in the diet. Damage to reproductive tract by inseminating cows not in true heat as well as from difficult calving or venereal infection, especially trichomoniasis, spread by natural service, also result in severe uterine infection. Poor quality water from contaminated wells or ponds, routine use of uterine boluses or infusion may cause sterile pus condition or increase infections. Hence, it is evident that successful reproductive health management should include educating farmers about maintaining hygiene as well as judicious animal handling procedures. Post-partum local infections of the uterus delay uterine involution, cause inflammation of the endometrium, delay the interval to first ovulation postpartum,reduce conception rate (C R) to first insemination and increase the risk of culling for infertility. Studies conducted at NDRI showed that cows with uterine diameter d” 5 . 1 c m 1 2 d p ost-p a rtum ar e mo re like ly to c o nce ive a t first ser vic e a nd
increase conception at first service by 17% in comparison to cows having larger uterine diameter. Further studies showed that the presence of purulent uterine discharge or cervical diameter e”7.5 cm after 20 days in milk (DIM), or muco-purulent discharge after 26 DIM is indicative of cows suffering with clinical endometritis. While the prevalence of clinical endometritis even in a well managed NDRI farm was 16.9%, such cows took 27% longer time to become pregnant, and were 1.7 times more likely to be culled for reproductive failure than cows without endometritis. Coupled with the loss in fertility, uterine infections have also been associated with decrease in milk production.