EFFECT OF RECOMBINANT BOVINE SOMATOTROPIN TREATMENT ON MILK PRODUCTION AND REPRODUCTIVE PERFORMANCE OF EWES AND GROWTH PERFORMANCE OF THEIR OFFSPRINGS. | ||
| Journal of Animal and Poultry Production | ||
| Article 4, Volume 34, Issue 5, May 2009, Pages 4517-4532 PDF (584.61 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/jappmu.2009.116993 | ||
| Authors | ||
| A. E. Abdel-Khalek1; T. A.M. Ashmawy2; E. S.H. El-Gohary2; A. A. Sallam2; Doaa F. Teleb2 | ||
| 1Animal Production Department, Faculty of Agric., Mansoura Univ. | ||
| 2Animal Production Research Institute, Agricultural Research Center. | ||
| Abstract | ||
| This study was carried out to investigate the effect of administration of bovine somatotropin on milk yield, milk composition, reproductive performance of Rahmani crossbreed ewes, as well as, offspring growth. A total number of 40 mature healthy Rahmani crossbred ewes (1/2 Finnish Landrace x 1/2 Rahmani) aged from 3 to 4 years were divided into two similar groups (control and treatment). Ewes in the first group were injected with saline solution and served as a control, while those in the second group were s.c. injected with 160 mg recombinant bST at 14-day interval from one-month pre-partum until 3 months post-partum. Ewes were monitored for sign of oestrus and those observed in heat were mated using a fertile ram (breeding season from April to June). Milk yield and composition were determined throughout 8 lactation weeks. Results show that LBW of ewes at pre-partum and during the suckling period was not affected by rbST treatment, however, treated ewes were heavier (P<0.05) by about 5% than the control ones only during late post-partum. Administration of rbST increased (P<0.05) average daily milk yield of ewes during the 1st eight weeks of lactation, and the magnitude of the increase during the eight lactation weeks ranged between 16 to 33%. Milk fat, protein and total solids percentages were significantly lower (P<0.05) in treated than in control ewes. Meanwhile, lactose and ash contents did not differ significantly between the two groups. Male and female lambs of treated ewes were heavier (P<0.05) during the suckling period compared with those of the control group. Lambs of treated ewes reached the weaning weight (12 kg) earlier (at 6 and 7 weeks for male and female, respectively) than those of the control ewes (8 weeks). Average daily gain of male and female lambs of treated ewes was higher (221 and 182 g/day, respectively) than that of the control (163 and 170 g/day, respectively). Treatment with rbST increased (P<0.05) oestrus/mating rate (40 vs. 70%) and reduced post-partum period of lambing ewes by about one month as compared to untreated ewes. Moreover, ewes treated with rbST showed greater (P<0.05) number of ovarian follicles and corpus lutea (18 and 21) than that of the control ones (5 and 10), respectively. Lambing rate was lower (P<0.05) in control than in treated ewes (30 and 75 vs. 60 and 85.7%), respectively. In conclusion,s.c. injection of 160 mg rbST at 14-day interval during one-month pre-partum and 3 months post-partum improved productive (milk yield) and reproductive (lambing rate) performance of ewes and their offspring growth. | ||
| Keywords | ||
| Ewes; somatotropin; milk yield; milk composition; lambs performance; reproductive performance | ||
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