Outcome of Gonadotropin Releasing Hormone Treatment 12 Days Post AI and Double Insemination on Conception Rate of Repeat Breeding Cows in Mekelle, Tigray, Ethiopia

Abstract

The aim of the present study was to determine outcome of gonadotropin releasing hormone analogue given 12 days post AI and double inseminations during estrous period of dairy cattle and improvement of conception rate. Field trial was carried out on repeat breeding cross breed dairy cows which are lactating, apparently healthy and exhibits estrus regularly. A total of Sixty three repeat-breeding cows from twenty eight herds were selected and assigned randomly in to three equal groups G (1, 2 and 3); two treated and one control group. Group1 (n=21) cattle were treated intramuscularly with 10 µg buserelin acetate 12 days post AI. Group2 (n=21) cattle were inseminated twice during estrus exhibition with 6-8 hours interval. Group3 (n=21) cattle were receive no treatment, inseminated once as heat was detected and considered as a control group. Dairy cows were examined for pregnancy after three months through rectal palpation. Pregnancy rates recorded were 52%, 38% and 28% in G1, G2 and G3 respectively. Conception rates of treated groups (G1 and G2) exceed control group by 24% and 10% respectively and showed a significant statistical variation (P<0.05) as compared to control groups. Comparison between treated groups also indicated that G1 has statistical significant difference from G2. From this experiment, it is recommended that use of GnRH 12 days can improve pregnancy rate as compared to double insemination and single service.