Effects of Gonadotropin-Releasing Hormone on Reproductive Performance of Early Postpartum Dairy Cows and Cystic Cows

Hwang, Woo Suk

Korean Journal of Veterinary Research 1981;21(1):59-64.

Woo Suk Hwang

College of Veterinary Medicine, Seoul National University

Gonadotropin-Releasing Hormone의 투여(投與)가 산욕기(産褥期)의 유우(乳牛)와 난소낭종유우(卵巢囊腫乳牛)의 번식효율(繁殖效率)에 미치는 영향(影響)

황우석

서울대학교 수의과대학

Abstract

Holstein-Friesian cows(n=284) were given $100{mu}g$ of gonadotropin-releasing hormone(GnRH) or saline solution by intramuscular injection at 10 to 22 days after parturition, and were investigated their reproductive performance and frequency of ovarian cysts. Among them 28 cystic cows were injected with $150{mu}g$ of GnRH intramuscularly and examined the recovery rate. The results obtained in this study were summarized as follows: 1. The interval from calving to 1st ovulation was reduced from 28.2 days in controls to 16.5 days for cows given GnRH (p<0.01). 2. The intervals from calving to 1st estrus and from calving to conception were extended significantly in control group (p<0.05). 3. Inseminations per conception and conception rate at 1st insemination did not reveal difference between two groups. 4. Frequency of ovarian cysts was reduced from 14.0% in control to 4.20% for cows given GnRH (p<0.05). 5. Of the 28 cystic cows receiving $150{mu}g$ of GnRH, 23(82.1%) responded to 1st treatment and returned to estrus $24.2{pm}4.3$ days after treatment. 6. These data provide evidence for reduction in infertility and reproductive disorders in early postpartum dairy cows given GnRH as a prophylactic.