S.M.K Naqvi

Development and application of ovine reproductive technologies: an Indian experience

Sheep play an important role in the Indian economy by providing employment to a large population of marginal and landless farmers. The production from native breeds is relatively low due to their poor reproductive efficiency. Embryo transfer technology can be utilised for faster multiplication of elite animal to increase the genetic gain. A great deal of research is involved to overcome the constraints in the technology, i.e. expensive and complicated nature of the technology and low success rate. In order to avoid surgical involvement, procedures of laparoscope aided embryo collection and transfer have been developed. Although the use of FSH of ovine origin has given more consistent superovulatory response, but it is still too low to get sufficient numbers of progeny from a donor ewe. The progress made in cryopreservation of ram semen has opened the possibility for conservation and utilisation of frozen semen of elite rams in sheep improvement programme. The lambing rate obtained after laparoscope aided intrauterine artificial insemination with frozen semen is encouraging but the impetus is now to develop the non-invasive transcervical insemination technique.

Impact of simulated heat stress on growth, physiological adaptability, blood metabolites and endocrine responses in Malpura ewes under semiarid tropical environment

The study was conducted to develop a simulated heat stress model for sheep depicting natural environmental conditions and to observe its impact on growth, reproductive performance, physiological adaptability, blood metabolites and endocrine responses in Malpura ewes. The experiment was conducted on 16 adult Malpura ewes for a period of 35 days. The animals were randomly divided into two groups of eight animals each (GI – control, GII – heat stress). The GII ewes were exposed to different temperature at different hours of the day i.e. 38°C at 1000–1100 hours; 40°C at 1100–1200 hours; 42°C at 1200–1300 hours; 43°C at 1300–1400 hours; 44°C at 1400–1500 hours and 42°C at 1500–1600 hours in a climatic chamber. Feed intake (P < 0.01), bodyweight (P < 0.05) and body condition score (P < 0.01) reduced significantly in GII as compared with GI ewes while water intake increased significantly (P < 0.01). All physiological responses also showed significant variation between the groups for treatment. In addition, all endocrine parameters showed highly significant (P < 0.01) variation for the treatment. Plasma cortisol increased significantly (P < 0.01) while T3 (P < 0.01) and T4 (P < 0.01) decreased significantly in GII as compared with GI ewes. Further, plasma oestradiol decreased significantly (P < 0.01) while plasma progesterone increased significantly (P < 0.01) in GII as compared with GI. Among the biochemical parameters, hemoglobin, packed cell volume, plasma glucose, total cholesterol, urea and blood urea nitrogen differed significantly between the groups. In addition, oestrus duration also significantly (P < 0.05) reduced in GII as compared with GI. Based on the results obtained from the study it can be concluded that simulated heat stress influenced the adaptive behaviour of sheep in terms of changes in physiological, blood biochemical and endocrine responses. Ultimately, their growth and reproductive performance are compromised during the process of adaptation to the simulated heat stress.

Effect of freezing temperature, at which straws were plunged into liquid nitrogen, on the post-thaw motility and acrosomal status of ram spermatozoa

The present study was conducted to observe the effect of initial freezing temperature on subsequent survival and acrosomal integrity of Malpura and Bharat Merino ram spermatozoa during post-thawing incubation. Semen samples were diluted in TEST-yolk-glycerol extender, loaded in 0.25 ml straws and cooled down to -25, -75 or -125 degrees C freezing temperature using a programmable cell freezer. Computer assisted sperm analysis and acrosomal integrity of thawed samples were assessed after thawing and at hourly intervals during incubation at 37 degrees C for 4 h. The percentage of motile cells in samples frozen at -125 degrees C were 80.3 and 63.7 after post-thawing and -thawing incubation, compared to 75.9 and 39.7 at -25 degrees C or 73.9 and 51.8 at -75 degrees C temperatures, respectively. The spermatozoa with normal acrosome were also significantly, respectively, higher in samples frozen at -125 degrees C, compared to -25 and -75 degrees C temperatures. There were no significant breed variations on percentage of motile, percentage of rapidly motile cells, percentage of normal acrosomes, curvilinear velocity and lateral head displacement except straight line velocity and average path velocity of spermatozoa. The results indicated that -125 degrees C initial freezing temperature conferred the best cryopreserving ability to ram spermatozoa for post-thawing thermoresistance test compared to -25 or -75 degrees C freezing temperature.

Ovarian response and embryo recovery to different superovulatory regimens in Rambouillet ewes under semi-arid conditions

Abstract Twenty four adult Rambouillet sheep were allocated in equal number to three groups and treated for superovulation using 800 IU pregnant mare serum gonadotrophin (PMSG) and GnRH (4xa0μg) (Group 1); PMSG (400 IU) in conjunction with FSH (8xa0ml; Ovagen) (Group 2) and FSH-P (18xa0mg) (Group 3). Estrous in all the ewes was synchronized by means of two 10xa0mg injections of prostaglandin F2α (PG), administrated at a 10 day interval. Superovulation treatment started 48xa0h prior to last PG injection. When in estrous, the ewes were naturally mated with Rambouillet rams. Ovarian examination and embryo/ova recovery were performed at laparotomy on either day 3 or 4 after mating. All the ewes exhibited estrous at ≤72xa0h after the last PG injection. The interval from the last PG injection to the onset of estrous was significantly (P 2 CL) and ova/embryo recovery rate were lower (P

Cervical penetration and transcervical AI of tropical sheep (Malpura) at natural oestrus using frozen-thawed semen

Abstract This study comprising of two trials was undertaken in ewes exhibiting natural oestrus to evaluate a simple transcervical artificial insemination technique suitably modified for use in tropical sheep. Twenty four adult multiparous Malpura ewes which had lambed 6 to 12 months prior to the experiment were utilized for two oestrous cycles during the autumn breeding season. The cervical penetration ( n =47) was conducted in both first ( n =24) and second ( n =23) trial ≤6 to 18 h following onset of oestrus, while lambing rate was assessed in the second trial ( n =23) following deposition of frozen-thawed semen having >70% mean post-thaw motility at os, mid cervix or uterus. The overall success achieved in cervical penetration was 44.7%. There was no difference in cervical penetration rate at ≤6 and 18 h after detection of oestrus (46.1% vs. 42.8%, respectively). A mean lambing rate of 22.7% was recorded in ewes inseminated using this technique. Mid cervical and transcervical insemination with frozen semen resulted in similar lambing rate (28.5 vs. 22.7%, respectively). However, no lambing was achieved on os-cervical insemination. Further efforts are needed to determine factors controlling the cervical penetration and conception rate following artificial insemination with frozen semen.

Ideal proportion of roughage and concentrate for Malpura ewes to adapt and reproduce in a semi-arid tropical environment

The study was designed to identify the most appropriate roughage to concentrate ratio for Malpura ewes under semi-arid tropical environments. The study was conducted for a period of 35xa0days and included 30 (2xa0years old) non-pregnant Malpura ewes weighing between 30 and 35xa0kg. Estrus synchronization was carried out in all the animals using indigenously developed intravaginal sponges impregnated with progesterone. The ewes were randomly divided into three groups (nu2009=u200910/group) namely R50 (nu2009=u200910; roughage to concentrate, 50:50), R60 (nu2009=u200910; roughage to concentrate, 60:40), and R70 (nu2009=u200910; roughage to concentrate, 70:30). Individual feed and water intake was recorded on a daily basis throughout the course of the study. Growth variables, physiological responses, blood metabolites, and endocrine responses were estimated at weekly intervals. Results of the study indicated that nutritional treatment significantly influenced growth variables including body weight (pu2009<u20090.01), BCS (pu2009<u20090.01), feed intake (pu2009<u20090.05), and water intake (pu2009<u20090.01) among the different treatment groups. The highest growth variables were recorded in R50 whereas the lowest were in R70. Both respiration rate (pu2009<u20090.01) and plasma estradiol levels (pu2009<u20090.05) also showed a similar trend as that of the growth variables. However, growth hormone (pu2009<u20090.01), T3 (pu2009<u20090.01), Hb (pu2009<u20090.01), glucose (pu2009<u20090.05), and estrus duration (pu2009<u20090.05) demonstrated a reverse trend with highest values recorded in R70 and lowest in R50. However, the nutritional treatment did not influence pulse rate, rectal temperature, T4, progesterone, PCV, total cholesterol, total protein, albumin, estrus%, and estrus cycle length. Since the additional concentrate supplementation in R50 and R60 did not improve the production variables, it can be concluded that providing 70xa0% roughage and 30xa0% concentrate could be a more appropriate and economically feasible ration composition for Malpura ewes reared in semi-arid tropical environments.

Effect of dietary regimens on ovarian response and embryo production of sheep in tropics

Abstract Bharat Merino ewes (n=24) maintained in a tropical environment were allocated to three dietary treatment groups. The ewes were grazed on pasture either without supplementation (Group 1) and with supplementation of concentrate feed at the rate of 150xa0g per ewe per day (Group 2) or 300xa0g per ewe per day (Group 3), respectively. Estrus was synchronized with two injections of prostaglandin (PGF2α) 10xa0mg at 10 days interval. Superovulation treatment commenced 3 days prior to the second injection of PGF2α. Each ewe received a total dose of 5.4xa0mg FSH every 12xa0h over 4 days and PMSG (200xa0IU) once at the start of the treatment. The ewes in estrus were exposed to fertile rams. Ovarian examination and recovery of embryos and ova were based on laparoscopy and laparotomy between days 3 and 6 after mating. Data for onset of estrus, duration of estrus, number of corpora lutea (CL), number of unovulated large follicles (LF), embryo recovery rate, embryo quality and fertilization were recorded. Onset of estrus after the second dose of PGF2α and duration of estrus did not differ significantly among the three groups. Number of ovulations, ovarian response (CL+LF), embryo recovery and yield of transferable embryos for all the dietary treatment groups were similar (P>0.05). It is concluded that the dietary flushing of Bharat Merino ewes prior to superovulation and mating did not influence the estrus response, superovulatory response, embryo recovery or yield of transferable embryos.

Effect of FecB status on the allometric measurements and reproductive performance of Garole × Malpura ewes under hot semi-arid environment

The study was conducted with the primary objective to establish the influence of FecB gene mutation on the growth and reproductive performance of Garole × Malpura ewes. The duration of the study was for 5xa0months involving 97 adult Garole × Malpura (GM) ewes. These 97 animals were segregated based on FecB genotype and the animals were divided into three groups as group I (FecBBB; nu2009=u200913), group II (FecBB+; nu2009=u200965), and group III (FecB++; nu2009=u200919). All the animals were kept under semi-intensive management system by subjecting the animals to grazing during day time and housing them in the night. Apart from grazing, ewes were provided with concentrate mixture at the rate of 150xa0g/day/ewe. The ewes in estrus after 12xa0h of onset of estrus were hand mated twice at 12-h intervals with a ram of proven fertility in the morning and evening. The pregnancy was confirmed by real time B-mode transabdominal ultrasonography. The experiment was continued until lambing. Under the treatments of different FecB genotype, the ewe’s growth and reproductive parameters were assessed. FecB genotype significantly (Pu2009<u20090.05) influenced body weight, heart girth, pin shoulder length, height at wither, lambing percentage, litter size, twinning percentage, and birth weight of lambs. From this study, it can be concluded that breeding Galore and Malpura breed shall help insure an economically viable production system.