title: Plasma progesterone profile and conception rate following exogenous supplementation of gonadotropin-releasing hormone, human chorionic gonadotropin, and progesterone releasing intra-vaginal device in repeat-breeder crossbred cows.
abstract: OBJECTIVE
  This study was designed to evaluate the effect of gonadotropin-releasing hormone (GnRH), human chorionic gonadotropin (hCG), and progesterone impregnated intra-vaginal device on progesterone profile and conception rate in repeat-breeding crossbred cows.
  
  
  METHODS
  Repeat-breeding crossbred cows aged 3-8 years (n=32), lactating and negative to white side test were randomly divided into four groups: Group 1 (Control, n=8), Group 2 (GnRH at 10 µg i.m, n=8), Group 3 (hCG at 1500 IU i.m., n=8), and Group 4 (progesterone impregnated intra-vaginal device at 958 mg, n=8). All the treatme nts were given on 5(th) daypostbreeding and in Group 4 intra-vaginally implanted device was withdrawn on 9(th) day (i.e., implant inserted for total 4 days) of the estrous cycle. Blood samples were collected on day 0, 5, 10, 15, and day 20 of estrous cycle, and plasma was separated for progesterone estimation.
  
  
  RESULTS
  Accessory corpus luteum was not formed in crossbred cows of Group4 and control group. However, total 6 and 8 accessory corpora lutea were found in Group 2 and Group 3, respectively. In pregnant cows, the plasma progesterone concentration increased continuously from day 0 to day 20. In non-pregnant cows, it increased from day 0 to day 15 and then declined. The conception rate on day 60 in Group 1, Group 2, Group 3, and Group 4 was 37.5%, 50%, 75%, and 37.5%, respectively.
  
  
  CONCLUSIONS
  Treating repeat-breeder cows with hCG is effective in increasing conception rate by developing accessory corpora lutea and higher progesterone level.
authors.affiliation: Department of Veterinary Gynaecology and Obstetrics, College of Veterinary & Animal Sciences, G.B. Pant University of Agriculture and Technology, Pantnagar - 263145, Uttarakhand, India.
authors.forename: N K J
authors.initials: NK
authors.lastname: Pandey
authors.affiliation: Department of Veterinary Gynaecology and Obstetrics, College of Veterinary & Animal Sciences, G.B. Pant University of Agriculture and Technology, Pantnagar - 263145, Uttarakhand, India.
authors.forename: H P
authors.initials: HP
authors.lastname: Gupta
authors.affiliation: Department of Veterinary Gynaecology and Obstetrics, College of Veterinary & Animal Sciences, G.B. Pant University of Agriculture and Technology, Pantnagar - 263145, Uttarakhand, India.
authors.forename: Shiv
authors.initials: S
authors.lastname: Prasad
authors.affiliation: Department of Veterinary Gynaecology and Obstetrics, College of Veterinary & Animal Sciences, G.B. Pant University of Agriculture and Technology, Pantnagar - 263145, Uttarakhand, India.
authors.forename: S K
authors.initials: SK
authors.lastname: Sheetal
keywords: gonadotropin-releasing hormone; human chorionic gonadotropin; progesterone impregnated device; repeat breeding