V. P. Maurya

Effect of induced body condition score differences on physiological response, productive and reproductive performance of Malpura ewes kept in a hot, semi‐arid environment

This study was undertaken to study the influence of induced body condition score (BCS) differences on physiological response, productive and reproductive performance of Malpura ewes to optimise BCS for these ewes for maximising production making it economically viable. The study was conducted for a period of 1 year using thirty healthy Malpura ewes (2-4 year old). The animals were randomly divided and different BCS was induced within three groups named Group I (BCS 2.5; n = 10), Group II (BCS 3.0-3.5; n = 10) and Group III (BCS 4.0; n = 10). The parameters included in the study were allometric measurements, physiological response, wool yield and reproductive performance. BCS had a significant influence on allometric measurements, respiration rate and different reproductive parameters studied, while wool production differed significantly during spring and non-significantly during autumn. The results revealed that the reproductive performance of Malpura ewes with a BCS of 3.0-3.5 was better in comparison with the groups with lower and higher BCS. It may be concluded from this study that an active management of breeding sheep flock to achieve a BCS of 3.0-3.5 may prove to result in an economically viable return from these flocks.

Effect of induced body condition score differences on sexual behavior, scrotal measurements, semen attributes and endocrine responses in Malpura rams under hot semi-arid environment

The study was conducted for a period of 45 days to assess the influence of body condition scoring (BCS) on reproductive efficiency of Malpura rams in terms of sexual behaviour, scrotal measurements, semen attributes and endocrine responses. The rams were randomly divided into three groups as group I (BCS = 2.5; n = 7), group II (BCS = 3.0; n = 7) and group III (BCS = 4.0; n = 7). Apart from grazing for 8 h a day, the rams were provided with concentrate mixture at the rate of 100, 300 and 500 g to groups I, II and III respectively to attain their respective BCS. Under these differential feeding regimes, sexual behaviour scrotal measurements, semen characteristics and endocrine parameters were studied at 15-days interval. Sexual behaviour, scrotal volume, scrotal circumference, testicular width, testicular length and scrotal skin thickness differed significantly (p < 0.05) between lower BCS group (group I) and higher BCS groups (groups II and III). The semen volume, mass motility and progressive sperm motility were recorded significantly (p < 0.05) higher in group II and lowest in group I. However, the sperm concentration did not differ significantly between the groups. The mean plasma testosterone concentration differed significantly (p < 0.05) between lower BCS group (group I) and higher BCS groups (groups II and III). Circulating plasma hormone concentrations were influenced due to the BCS. Plasma cortisol, T(3) and T(4) increased as the BCS improved from lower to higher. In conclusion, better reproductive efficiency of rams of moderate BCS (3.0 and 3.5) than rams of lower (2.5) and higher BCS (4.0) indicates the importance of maintaining optimum body condition of breeding rams under hot semi-arid environment.

Effect of thermal stress, restricted feeding and combined stresses (thermal stress and restricted feeding) on growth and plasma reproductive hormone levels of Malpura ewes under semi‐arid tropical environment

A study was conducted to assess the effect of thermal, nutritional and combined stresses (thermal and nutritional) on the growth, oestradiol and progesterone levels during oestrus cycles in Malpura ewes. Twenty-eight adult Malpura ewes were used in the present study. The ewes were randomly allocated into four groups, viz., GI (n=7; control), GII (n=7; thermal stress), GIII (n=7; restricted feeding) and GIV (n=7; combined stress). The animals were stall fed with a diet consisting of 60% roughage and 40% concentrate. GI and GII ewes were provided with ad libitum feeding while GIII and GIV ewes were provided with restricted feed (30% intake of GI and GII ewes) to induce nutritional insufficiency. GII and GIV ewes were kept in climatic chamber at 40°C and 55% RH for 6 h a day between 10:00 and 16:00 hours to induce thermal stress for a period of two oestrous cycles. Parameters studied were body weight, oestrus incidences, plasma oestradiol 17-β, plasma progesterone, conception rate, gestation period, lambing rate, and birth weight of lambs. The results indicate that combined stress significantly (p<0.05) reduced body weight, oestrus duration, birth weight of lambs, and oestradiol 17-β whereas significantly (p < 0.05) increased oestrus cycle length and progesterone. Furthermore, the results reveal that on comparative basis, ewes were able to better adapt in terms of growth and reproduction to restricted feeding than thermal stress. However, when restricted feeding was coupled with thermal stress it had significant (p<0.05) influence on body weight, average daily gain, oestradiol 17-β and progesterone concentrations. This showed that combined stress were more detrimental for these reproductive hormones in Malpura ewes under a hot semi-arid environment.

Production of prolific microsheep by embryo transfer into large non-prolific sheep

The Garole is a prolific breed of microsheep that possesses the FecB gene, which increases ovulation rate. The purpose of this study was to compare embryo production by multiple ovulation in seven Garole ewes with that in seven normal size, non-prolific Malpura ewes, and assess the influence of the large body size of Awassi crossbred recipient ewes on the birthweight of Garole lambs. Oestrus was synchronised with two intramuscular injections of 7·5 mg prostaglandin F2α administered 10 days apart. The donor ewes were superovulated by the use of pregnant mare serum gonadotrophin and follicle-stimulating hormone. The onset and duration of oestrus were similar in both breeds. The Garole donors had higher total mean (se) ovarian responses (15·6 [3·6] v 9·1 [2·3]), ovulation rate (13·6 [3·1] v 8·4 [2·2]) and produced more transferable embryos (6·0 [3·5] v 4·0 [0·9]) than the Malpura donors, but the differences were not statistically significant. The Garole lambs produced by embryo transfer were on average 57·8 per cent heavier at birth than contemporary Garole lambs produced by natural mating.

Production of 24 transferable embryos in one flush by a Garole microsheep

FIG 2: Ovaries of a superovulated Garole ewe, showing multiple ovulations An adult parous Garole ewe weighing 12·5 kg, belonging to a flock that was procured from the Sunderban area in October 2000 and raised under a semi-intensive management system at the institute’s farm, was induced for superovulation in late autumn 2004 under the multiple ovulation embryo transfer programme being conducted at the institute. Oestrus was synchronised by the administration of two intramuscular injections of 10 mg prostaglandin F2α (PGF2α) (Lutalyse; Pharmacia), 10 days apart. Superovulatory treatment commenced three days before the second PGF2α injection: the ewe received a total dose of 5·4 mg of ovine follicle-stimulating hormone (Ovagen; ICP), intramuscularly twice a day, at 07.30 and 18.30, at a constant dose over a four-day period. A dose of 200 IU pregnant mare serum gonadotrophin (Folligon; Intervet) was also administered intramuscularly at the start of the superovulation treatment. Oestrus in the ewe was detected with the aid of an aproned ram of high sexual vigour at six-hourly intervals for three days, beginning on the day of the second PGF2α injection. The ewe was then subjected to mating twice a day, in the morning and evening, with a Garole ram of proven fertility. The ovarian response in terms of the number of ovulations was determined by laparoscopic examination four days after mating. Surgical embryo collection was performed as described by Naqvi and others (2001). The ewe was fasted for at least 24 hours before the surgical intervention. The abdominal area anterior to the udder was shaved and sprayed with 70 per cent alcohol, and the ewe was sedated with xylazine hydrochloride (Xylazine; Indian Immunologicals) and locally anaesthetised by the infiltration of lignocaine hydrochloride (Xylocaine; AstraZeneca). After visualisation of the reproductive tract through the laparotomy, the uterine horn was carefully exposed to at least the bifurcation of the two horns. The flushing medium, 20 ml Dulbecco’s phosphate buffered saline, pH 7·5 (± 0·3) at room temperature, supplemented with 2 per cent bovine serum albumin (Sigma Chemical) was introduced into the base of the uterine horn using a blunt Jelco needle attached to a syringe. The medium was flushed towards the tip, where it was collected through a polythene catheter (outer Production of 24 transferable embryos in one flush by a Garole microsheep