Influence of some hormonal treatments on postpartum reproductive performance and progesterone profile in Friesian cows under summer and winter conditions
Abstract: The aim of the present study was to determine the effect of administration of hCG, GnRH, or P4 after artificial insemination (AI) on serum progesterone concentration and some reproductive performance of repeat breeder Friesian cows during winter and summer. In this experiment 48 Friesian cows (24 in Winter and 24 in Summer) were used. After AI, cows in winter were assigned randomly to four equal groups, after balancing for daily milk production and parity, as follows: G I (n=6) received an intramuscular injection of 3000 IU hCG (Pregnyl, Novarel) on the 7th day after AI, G2 (n=6) received 100 mg of progesterone (Prontogest, Marcyrl) intramuscularly on the 2nd , 3rd , 4th , 6th and 9th days after AI. GJ (n=6) received an intramuscular injection of 10 μg GnRH (Receptal, Intervet) on the 12th day after AI. The last group; G4 (n=6):cows were left untreated and served as control. Concentrations of progesterone in serum were increased significantly in treated cows as compared to the control. The results demonstrated that treated cows were more responsive in summer than in winter regarding to serum progesterone concentration. Compared to control group, it was identified that GnRH or hCG administration significantly increased conception rate and decreased days open. Number of services/conception was reduced by hormonal treatments but differences were not significant. In conclusion this study supports the use of either hCG, or GnRH postinsemination as a method for enhancing pregnancy rates in lactating repeat breeder dairy cattle especially in slimmer under Egyptian condition.
Keywords: hCG. progesterone. GnRH, seasons. conception rate. days open, Friesian cows.
Publication year 2013
Pages 67-77
Availability location معهد بحوث الانتاج الحيوانى-شارع نادى الصيد- الدقى - الجيزة
Availability number
Organization Name
serial title Egyptian Journal Basic Applied Physiology
ISSN 1687-1146
Author(s) from ARC
External authors (outside ARC)
    فاروق عبد الله السيد خليل جامعة عين شمس
    عصمت بكرى عبدالله جامعة عين شمس
Agris Categories Animal physiology - Reproduction
AGROVOC
TERMS		 Artificial insemination. Cows. Gnrh. Milk production. Progesterone. Reproductive performance. Seasons. Summer. Winter.
Proposed Agrovoc days open;hCG;serum progesterone;parity;
Publication Type Journal
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