EFFECT OF GNRH INJECTION ON REPRODUCTIVE PERFORMANCE OF NEW ZEALAND WHITE DOE RABBITS | ||||
| Journal of Animal and Poultry Production | ||||
| Article 5, Volume 6, Issue 6, June 2015, Page 393-405 PDF (274.7 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jappmu.2015.52893 | ||||
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| Authors | ||||
| Tork M.I. Dorra; A H. M. Raya; Amira M. Mansour | ||||
| Poultry Production Department, Faculty of Agriculture, Mansoura University, Egypt. | ||||
| Abstract | ||||
| The present study was undertaken to investigate the effects of GnRH injection on reproductive performance of NZW rabbit does. The experimental work was conducted at International Livestock Management Training Center (ILMTC), Sakha, Animal Production Research Institute, Kafr El-Shiekh Govermorate, in co-operation with Poultry Production Depatment in the Rabbit Research Unit; Agricultural Researches and Experiments Station; Faculty of Agriculture, Mansoura University, Egypt. A total of 48 rabbit does of body weights ranging from 2.75 to 3.5 kg were equally divided into three groups of 16 doe each. They were further subdivided into two sub-groups. The 1st sub-group (8 does) was intramuscularly injected with 2.5 mL saline solution post-kindling and served as a control, and the second half (8 does) was intramuscularly injected after kindling (0 day) with 2.5 mL of GnRH analogue per doe (Receptal, Intervet equivalent B.V. Boxmeer-Holland, each ml of Receptal contained 0.0042 mg Buserelin acetate equivalent to 0.004 mg Buserelin) (G1). The same injection procedures and tested dose (2.5 mL/doe) of GnRH were applied on the second and third experimental sub-groups of rabbit does at 5 and 10 days post-kindling (G2 and G3), respectively. After parturition, conception rate and the size of the litter (total and live borns at birth), were recorded. Plasma concentrations of progesterone was determined at 0,7,14,21,28 day after kindling. The obtained results could be summarized as follows: Injection of GnRH improved fertility of rabbit does in term of litter size and overcome other treatments. Since the GnRH-treated group (3) had the highest litter size at birth (8.2) followed by G1 (5.00) then G2 (1.8) youngs. Litter size at birth was significantly improved by either saline or GnRH injection at day of kindling (day 0) or day 10 post-kindling. The values obtained for litter size were (4.00 and 5.88 vs. 1.63), for live bunnies (3.25 and 5.13 vs. 1.38) and for viability rate of bunnies at birth (61.25 and 65.35 vs. 31.25%), for G1 and G3 compared with the G2, respectively. The overall mean of viability rate at birth was 66.3%,32.1%,72.5% in treatments groups (G1,G2 and G3), respectively. There were significant difference between treatments on the means of viability rate of youngs at birth, which were 71.3, 32.9,79.6% and 61.2, 31.2, 65.3% for control, G1, G2 and G3 groups, respectively. It was observed that hormonal treatment of does in G1 and G3 improved conception rate from 75% to 87.5% compared with 37.5% for G2. The differences between saline-injected (control) and GnRH injected groups were not significant, however, the time of injection has the greatest influence on conception rate. In this respect the present results showed that GnRH and control injection at 5 days post-kindling gave the lowest conception rate. Means of plasma progesterone concentration of rabbit does at 0;7;14;21 and 28 days of pregnancy in the control and treated does was not significantly affected. It is concluded that GnRH injection at day of kindling or 10 days post-kindling may be used as a tool for improving the reproductive traits of NZW rabbit does. | ||||
| Keywords | ||||
| GnRH; does rabbits; reproductive performance; progesterone | ||||
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