MANAGEMENT OF REPEAT BREEDING IN GIR COWS USING HORMONAL THERAPY
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Date
2012
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AAU, Anand
Abstract
This study was carried out on 24 repeat breeding Gir cows of Muniseva Ashram Gaumandir, Goraj, Waghodiya, Vadodara, during the period from October 2011 to March 2012, to evaluate the relative efficiency of various hormonal treatments towards enhancing their reproductive performance together with the evaluation of weekly plasma progesterone profile and various blood biochemical and macro-micro minerals from the day of treatment up to 6 weeks post-treatment. All the breedable females (n=215) of the herd were screened clinically and by per rectal examinations to know the incidence of reproductive problems. Twenty four repeat breeding cows selected were divided at random .in to four groups, 6 animals in each. Animals of group I were treated with single i/m injection of 0.02 mg buserrlin acetate (GnRH analogue; 5 ml Receptal, Intervet India Ltd.) and those of Group II with single i/m injection of 1500 lU hCG (Chorulon, Intervet India Ltd.) immediately after natural breeding, while animals of Group III were administered with 500 mg of hydroxy-progesterone caproate (Proluton depot, Zydus Cadila.) on 6th day of natural breeding and those of Group IV bred at estrus without any treatment served as control. Blood samples were collected in heparinized vials on day 0 (estrus) and then at weekly interval up to 6 weeks post-breeding in GnRH, LH and control groups, except in progesterone group in which blood was collected on day 0 (estrus), day 6 just before treatment) and then at weekly interval up to 6 weeks. Plasma samples separated were stored deep frozen at -20°C with a drop of Merthiolate until analyzed. The incidence of repeat breeding was almost similar in adult cows and heifers (46.87 vs 45.45%) with an overall incidence of repeat breeding as 46.51 (100/215) per cent. The incidence of anestrus condition was observed to be higher in cows than the heifers (25.00 vs 18.18 %) with an overall mean of 23.25 (50/215) per cent. In repeat breeding Gir cows, the first service and overall conception rates obtained following hormonal treatment with GnRH were 50.00 and 66.66, with LH 83.33 and 83.33 and Progesterone 50.00 and 66.66 per cent, respectively, with an overall mean of 61.11 and 72.22 per cent. These figures were significantly higher (P<0.01) than those (16.66 and 33.33 %) obtained in untreated control repeat breeding cows. The pooled mean plasma progesterone concentrations in all three hormones GnRH, LH/hCG and progesterone treated and control group were 3.712 ± 0.377, 4.823 ± 0.371, 3.973 ± 0.458 and 2.813 ± 0.381 ng/ml, respectively, with an overall mean of 3.830 ± 0.205 ng/ml. The progesterone value was at basal level on the day of estrus, which increased significantly (P<0.05) by 7th day post-estrus, fluctuated insignificantly till 6th week with the peak value on 5th week post-oestrus. In LH treated cows, the mean plasma progesterone value was significantly (P < 0.05) higher as compared to control group (4.823 ± 0.371 vs 2.813 ± 0.381 ng/ml). The mean plasma P4 levels in conceived and non-conceived groups were 5.266 ± 0.277 and 2.394 ± 0.207 ng/ml (P <0.01). The progesterone concentration in conceived group remained more or less at constant high level till 6th week post-breeding, while in non-conceived cows it showed rising trend up to 2nd week followed by drop on 3rd week (1.016 ± 0.171 ng/ml), which then again rose gradually and significantly to reach second peak on 5th week (4.616 ± 0.394 ng/ml), again dropped at 6th week and thus showed a cyclic trend suggestive of repeat estruses. The overall mean values of biochemical constituents, viz., plasma total protein, total cholesterol and triglycerides were 9.786 ± 0.084 g/dl, 217.857 ± 2.570 mg/dl and 61.008 ± 1.137 mg/dl, respectively. There was no any significant difference among treatment groups as well as between conceived and non-conceived groups, or even between weeks within the group. However, the mean plasma concentration of cholesterol was lower in LH treated group as compared to untreated control group. The overall mean values of macro-minerals, viz., calcium, inorganic phosphorus, Ca:P ratio and magnesium were 11.918 ± 0.159 mg/dl, 8.193 ± 0.123 mg/dl, 1.516 ± 0.032 and 1.818 ± 0.028 mEq/L without significant differences between conceived and non-conceived groups or between weeks, except Ca:P ratio and magnesium. The mean plasma magnesium levels in GnRH, LH and Progesterone treated groups were 2.341 ± 0.047, 1.731 ±0.023 and 1.620 ± 0.021 mEq/L, respectively. The differences among treated groups were significant (P<0.05) only for this trait. The overall mean values of trace elements, viz., zinc, iron, copper and manganese were 1.549 ± 0.008 ppm, 2.119 ± 0.023 ppm, 0.779 ± 0.005 ppm and 0.090 ± 0.001 ppm, respectively. The mean concentrations of zinc and copper were significantly (P < 0.05) higher in three treated (GnRH, LH and Progesterone) groups as compared to untreated control repeat breeding cows. The values were significantly higher (P < 0.01) in conceived group as compared to non-conceived group for zinc (1.587 ± 0.012 vs 1.511 ± 0.011 ppm), iron (2.238 ± 0.018 vs 2.001 ±0.038 ppm), copper (0.834 ± 0.007 vs 0.724 ± 0.002 ppm), and manganese (0.094 ±0.001 vs 0.087±0.001 ppm), and they varied significantly between weeks for copper and manganese also. Overall, the plasma P4 profile helped to monitor the cyclic rhythm of repeat breeder cows and the hormonal therapy, especially LH, was found highly effective in solving repeat breeding problem in Gir cows of the herd investigated.
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MANAGEMENT