Nath, K.C.DUTTA, LAKSHYA JYOTI2018-09-062018-09-062017-07http://krishikosh.egranth.ac.in/handle/1/5810072086A study was conducted on a total of 909 crossbred cows maintained in 60 private farms of Kamrup, Darrang and Lakhimpur districts of Assam with the primary objectives of identification and characterization of common reproductive disorders and studying fortification needs of commonly practised therapeutic techniques for the treatment of infertility. Incidence of reproductive disorder was determined based on breeding history provided by the animal owners and clinico-gynaecological examination of 133 problem breeder cows. The study revealed that overall incidence of infertility was 14.63 per cent comprising 5.28 per cent for repeat breeding with uterine infection, 3.41 per cent for repeat breeding without uterine infection, 2.97 per cent for true anoestrus, 2.53 per cent for silent oestrus and 0.11 per cent for each of pyometra, ovarian cyst, infantile genital organ and ovario-bursal adhesion. Out of the total number of infertile cows 59.39 per cent suffered from repeat breeding and 37.59 per cent anoestrus. Poor management system in respect of flooring, drainage, sunlight exposure, ventilation and roofing of the cattle shed was associated with higher incidence of infertility with the frequency of occurrence of 58.69, 28.10, 17.11, 51.28 and 21.47 per cent respectively against 12.28, 11.0, 12.60, 12.98 and 9.38 per cent for good flooring, good drainage, good sunlight exposure, good ventilation and good roofing system respectively. Feeding condition was normal in 48.33 per cent and poor in 51.66 per cent cattle farms. Incidence of infertility was 13.36 and 15.78 per cent under normal and poor feeding conditions respectively. Of the infertile cows 53.38 per cent had body condition score between 2.5 and 3.5 and 46.61 per cent had the score less than 2.5. Out of repeat breeder cows with uterine infection 43.66 per cent had good body condition and 27.41 per cent poor body condition. Level of serum calcium, zinc, leptin, ghrelin and IGF-1didnot vary significantly between types of infertility. Level of phosphorus and iron was low in cows affected with repeat breeding due to infection. Serum oestrogen level remained significantly low in cows affected with silent oestrus and true anoestrus while level of progesterone was significantly higher in cows affected with silent oestrus. Treatment of silent oestrus in crossbred cows with double injection of PGF2α 11 days apart resulted in 100.00 per cent oestrus response and 66.66 per cent conception rate. Fortification of PGF2α with supportive treatment comprising oral bypass fat and mineral mixture and injectable phosphorus and vitamins did not improve conception rate. Supportive treatment alone when used in true anoestrus cows resulted in 83.33 per cent oestrus response and 50.00 per cent conception rate. Fortification of GnRH with supportive treatment did not improve conception rate in treating true anoestrus in cows. Fortification of intrauterine Lugol’s iodine with supportive treatment used for treating repeat breeding due to uterine infection resulted in higher post treatment conception rate of 83.33 per cent against 66.66 per cent obtained with Lugol’s iodine alone. The hormone hCG was the choice of drug for treatment of repeat breeding without uterine infection resulting in post treatment conception rate of 83.33 per cent which increased to 100.00 per cent when fortified with supportive treatment.en-USnullThesis