Physiological response of crossbred sheep under nutritional scarcity.

Nutritional scarcity during summer and winter is a major constraint for sheep rearing in the semi-arid tropical region. In this region, a new crossbred sheep has been developed by the crossing of a native sheep breed Malpura with a breed of hot-humid coastal region breed Garole. A study was conducted for 9 weeks to assess the physiological response of crossbred (Garole x Malpura x Malpura, GMM) rams under nutritional scarcity in the semi-arid tropical region. Eighteen adult crossbred rams were randomly allocated into three groups of six animals each. The groups are G1 (control, ad libitum feeding), G2 (20% less than ad libitum feeding), and G3 (30% less than ad libitum feeding). The animals were stall-fed with a diet consisting of 70% roughage (Cenchrus ciliaris hay) and 30% concentrate feed. Body weight gain, average daily gain, and feed intake were significantly (P < 0.05) lower in G2 and G3 as compared to G1 rams. Water intake was significantly (P < 0.05) higher in G2 and G3. Physiological responses, blood biochemical and endocrine profile did not differ between the groups. The results indicate that the crossbred rams evolved through the crossing of the hot semi-arid tropical region breed with hot humid coastal region breed are able to maintain their body homeostasis despite nutritional scarcity although their body weight decreased.

Effect of altered ambient temperature through shelter modifications on physiological indicators of Malpura lambs reared in semi-arid region during winter.

Microclimatic factors are of crucial aspect for the welfare of animals. Therefore, a study was conducted to assess the effect of altered ambient temperature through shelter modifications on physiological indicators of Malpura lambs reared in the semi-arid region during winter. Twenty-one Malpura lambs of 3-5 week age and average body weight 9.97 ±â€¯0.51 kg were used in the present study. The lambs were divided into three groups (eg. G1, G2, and G3) and were kept in the different microenvironment by manipulation of shelter design. The G1 lambs were maintained at lower minimum temperature (8.59 ±â€¯0.71 °C) in asbestos roofed shed, while G2 lambs were maintained at higher minimum temperature (14.59 ±â€¯0.54 °C) in local handmade bamboo dome structure, and G3 lambs were kept at a medium minimum temperature (11.84 ±â€¯0.64 °C) in thermocol insulated roofed shed from evening 18:30 h to morning 07:00 h. The study was carried out for one month between January and February. The parameters studied were physiological response (respiration rate, pulse rate, rectal temperature), skin temperature, blood metabolites and endocrine profile. The data were analyzed by general linear models. Higher average daily weight gain was recorded in the lambs kept in higher minimum temperature groups (20.54% higher in G2 and 24.68% higher in G3) as compared to G1 lambs. Microenvironment manipulation had no significant (P > 0.05) effect on most of the physiological response and skin temperature except morning respiration rate within low-temperature range. The present study reveals that Hb, PCV, T3, and cortisol level were significantly (P < 0.05) influenced by microenvironment manipulation. The results of the study indicated that altered ambient temperature through altered shelter design of housing for raising of lambs in the semi-arid tropical region may support animal welfare during chilling nights of the winter.

Effect of protection against hot climate on growth performance, physiological response and endocrine profile of growing lambs under semi-arid tropical environment.

In the hot semi-arid tropical region, extreme summer is a major constraint in sheep production. The growth performance of growing lambs is impaired during the summer. Therefore, the present study was conducted to assess the effect of protection against hot climate on growth performance, physiological response, and endocrine profile of growing lambs under semi-arid tropical environment. All the data in the experiment were presented as mean ± SE. Thirty Malpura lambs with the age of 122.7 ± 6.05 days and body weight of 19.52 ± 0.42 kg were allotted into three groups, viz. G1 (control, lambs kept in open area under tree shade), G2 (lambs kept in conventional asbestos-roofed shed), and G3 (lambs kept in designed shed). The allotment was based on their initial body weight so that the mean body weight of each group was similar. In all three types of protection, lambs were provided with sufficient space to move and social interaction. In asbestos-roofed shed (G2), all the four sides from ground to the roof were fenced with strong galvanized iron chain link. But in G3, all the four sides were constructed in a manner that there was 0.13 m air space between inner and outer solid brick columns of the wall up to 1.37 m height, and rest up to the roof was fenced with bamboo splint net. The air space between the two columns of the wall was filled with sand, and it was kept in moist condition by continuous water drips which provide extra evaporative cooling. The designed shed was basically constructed with bamboo. Tree shade was assured under the natural shades of large trees. The shaded area was protected by wire fences. The experiment was conducted for 45 days during very high temperature (May-June). The lambs were provided with ad libitum green fodder, dry roughage, 300 g concentrate, and ad libitum drinking water. The respiration rate at morning and afternoon, pulse rate at morning and afternoon and rectal temperature at afternoon was significantly (P < 0.05) lower in lambs of G3 as compared to other groups. The final body weight did not differ significantly between the groups, but average daily gain (g/day) was higher in G3 (150.06 ± 11.13) as compared to the G1 (109.69 ± 18.10). The feed conversion rate (FCR) was significantly (P < 0.05) better in G3 (5.49 ± 0.08) as compared to G1 (7.65 ± 0.08) and G2 (6.60 ± 0.08). The hemoglobin level was significantly (P < 0.05) higher in G1. The endocrine profile did not vary significantly (P > 0.05) among the groups, but insulin-like growth factor-1 (IGF-1) was higher in G3. It can be concluded from this study the lambs provided with better protection during summer remained in more comfortable condition, showed better FCR, and although not statistically significant showed better growth performance.

Effect of high ambient temperature on behavior of sheep under semi-arid tropical environment.

High environmental temperature is a major constraint in sheep production under semi-arid tropical environment. Behavior is the earliest indicator of animal's adaptation and responses to the environmental alteration. Therefore, the objective of this study was to assess the effects of high ambient temperature on the behavior of sheep under a semi-arid tropical environment. The experiment was conducted for 6 weeks on 16 Malpura cross (Garole × Malpura × Malpura (GMM)) rams. The rams were divided equally into two groups, designated as C and T. The rams of C were kept in comfortable environmental conditions served as control. The rams of T were exposed to a different temperature at different hours of the day in a climatic chamber, to simulate a high environmental temperature of summer in semi-arid tropic. The behavioral observations were taken by direct instantaneous observation at 15-min intervals for each animal individually. The feeding, ruminating, standing, and lying behaviors were recorded twice a week from morning (0800 hours) to afternoon (1700 hours) for 6 weeks. Exposure of rams to high temperature (T) significantly (P < 0.05) decreased the proportion of time spent in feeding during the observation period in most of the hours of the day as compared to the C. The proportion of time spent in rumination and lying was significantly (P < 0.05) lower in the T group compared to the C. The animals of T spent significantly (P < 0.05) more time in rumination in standing position as compared to the C. The overall proportion of time spent in standing, panting in each hour, and total panting time was significantly (P < 0.05) higher in the T as compared to the C. The result of the study indicates that the exposure of sheep to high ambient temperature severely modulates the behavior of sheep which is directed to circumvent the effect of the stressor.

Study of circadian rhythmicity of physiological response and skin temperature of sheep during summer and winter in semi-arid tropical environment.

The present study aimed to evaluate the circadian rhythmicity of some physiological variables, including rectal temperature (RT), respiration rate (RR), heart rate (HR) and skin temperature (ST) in sheep during the summer and winter in semi-arid tropical environment. Eight Malpura rams of 3-4year of age with an average body weight of 37.1±1.99kg were selected for the study. All the animals were fed individually for a maintenance requirement on a body weight basis. The RT, RR, HR and ST values were measured in each animal at 3hour intervals for 24 consecutive hours. Ambient temperature (DBT) and relative humidity (RH) was also recorded inside the shed at the time of physiological parameter study. The cosinor analysis showed a daily circadian rhythm (P<0.01) in RR, HR and ST values during the summer and winter in sheep under semi-arid environment. The RR, HR and ST differ significantly (P<0.05) between summer and winter. The amplitude of RR, RT and ST differ significantly (P<0.05) between the seasons. The results indicate that the circadian rhythmicity of RR, HR, RT and ST during summer and winter changed as expected in compliance to the seasonal requirements of animal's adaptability.

Estrus synchronization and fixed-time artificial insemination in sheep under field conditions of a semi-arid tropical region.

A study was conducted to assess the success of estrus synchronization and fixed-time artificial insemination (FTAI) in sheep under field conditions of a semi-arid tropical region. A total of 471 ewes belonging to 17 farmers of four villages in Tonk district of Rajasthan (Jelmiya, Dhani Jaisinghpura, Tantiya and Bheepur) were synchronized for estrus during the years 2011 and 2012. Synchronization of estrus was done by AVIKESIL-S, cost-effective intra-vaginal sponges developed by the Institute and eCG protocol. The sponges were kept in situ in the vagina for 12 days and 200 IU eCG (Folligon, Intervet) was administered intramuscularly at the time of sponge withdrawal on the 12th day. Fixed-time cervical insemination was performed twice in ewes exhibiting estrus (restlessness, shaking of tail, slightly swollen vulva, moist and reddish cervical external os), 48 and 56 h after sponge removal, using liquid chilled semen of Patanwadi/Malpura rams containing 100 million sperm per dose. The estrus response recorded was 79.4 % (374/471) and lambing rate was 60.42 % (226/374). It may be concluded from the encouraging results of the present study that FTAI can be used effectively to take advantage of both the genetic improvement and economic benefit that can be realized by the use of estrus synchronization in conjunction with artificial insemination (AI).

Effect of time and depth of insemination on fertility of Bharat Merino sheep inseminated trans-cervical with frozen-thawed semen.

BACKGROUND: Artificial insemination (AI) can serve as a powerful tool to the sheep owners for making rapid genetic progress of their flock. The AI in sheep is mostly performed using fresh semen with two reasons i) lambing rate following trans-cervical AI with frozen semen is limited by the inability of frozen-thawed sperm to transit the cervix and ii) the need of circumventing the cervical barrier through laparoscope aided intrauterine AI. Therefore, AI with frozen-thawed semen is not as widespread in sheep as it is in other domestic species. However, to get maximum benefits through the use of AI, frozen-thawed semen is a prerequisite because instead of high fertility, the short shelf life of fresh semen coupled with a limitation on the number of insemination doses achievable per unit time restricts the widespread use of individual sires. Therefore, in order to enhance lambing rate, a total of 240 trans-cervical artificial inseminations with frozen-thawed semen were performed in Bharat Merino ewes during autumn season either once in the evening (G-I, 10 h after onset of estrus, n = 100) or twice (G-II, 14 h and 22 h after onset of estrus, n = 140) i.e. once in the morning and again in the evening. RESULTS: The pregnancy rate (proportion of pregnant ewes confirmed by ultrasonography at day 40) and lambing rate (proportion of ewes lambed) were higher in G-II as compared to G-I (26.4 vs 20% and 19.3 vs 10%, respectively). The difference in lambing rates was statistically (P < 0.05) significant. The depth of insemination within cervico-uterine tract had no significant effect on pregnancy and lambing rates. CONCLUSIONS: The results indicate that lambing rate in sheep following TCAI with frozen-thawed semen was significantly influenced by time of inseminations. Two inseminations after 14 and 22 h of onset of estrus enhanced the lambing rates of Bharat Merino sheep as compare to single insemination after 10 h of onset of estrus. The TCAI technique with frozen-thawed ram semen is promising and may serve as a valuable tool for genetic improvement of sheep breeds. Research efforts are going on worldwide to overcome the poor fertility following TCAI with frozen-thawed semen.