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A study was conducted to assess the combined effect of heat stress and nutritional restriction on growth and reproductive performances in Malpura rams. Twenty‐eight adult Malpura rams (average body weight (BW) 66.0 kg) were used in this study. The rams were divided into four groups: CON (n = 7; control), HES (n = 7; heat stress), NUS (n = 7; nutritional stress) and COS (n = 7; combined stress). The study was conducted for a period of 2 months. CON and HES rams had ad libitum access to their feed while NUS and COS rams were under restricted feed (30% intake of CON rams) to induce nutritional stress. The HES and COS rams were kept in climatic chamber at 42 °C and 55% relative humidity for 6 h a day between 10 : 00 h and 16 : 00 h to induce heat stress. Body weight increased significantly (p < 0.05) in CON as compared to NUS and COS. When compared within groups, scrotal width morning, scrotal width afternoon, scrotal circumference morning and scrotal circumference afternoon were significantly (p < 0.05) larger in CON while smaller in COS rams. The higher testicular length was recorded both during morning (p < 0.05) and afternoon (p < 0.01) in COS rams while the lowest in NUS rams. The highest plasma testosterone concentration was recorded in CON and lowest in COS rams. Semen volume and mass motility also differed significantly (p < 0.05) between the groups. The highest semen volume and mass motility was recorded in CON and NUS while lowest in both HES and COS rams. It can be concluded from this study that when two stressors occur simultaneously, they may have severe impact on reproductive performance of rams.  相似文献   
2.
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.  相似文献   
3.
A study was conducted to assess the effect of combined stresses (thermal and nutritional) on physiological adaptability and growth performance of Malpura ewes. Twenty-eight adult Malpura ewes (average BW 33.56 kg) were used in the present study. The ewes were divided into four groups, viz., GI (n = 7; control), GII (n = 7; thermal stress), GIII (n = 7; nutritional stress), 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 ewes) to induce nutritional stress. GII and GIV ewes were kept in climatic chamber at 40°C and 55% RH for 6 h/day between 1000 and 1600 hours to induce thermal stress. The study was conducted for a period of two estrus cycles. The parameters studied were feed intake, water intake, physiological responses (viz., respiration rate, pulse rate, and rectal temperature), body weight, and body condition scoring (BCS) of ewes. Both thermal and combined stress significantly (P < 0.05) affected the feed intake, water intake, respiration rate, and rectal temperature. The feeding schedule followed in the experiment significantly (P < 0.05) altered the body weight and BCS between the groups. The results reveal that when compared with thermal stress, nutritional stress had less significant effect on the parameters studied. However, when both these stresses were coupled, it had a significant influence on all the parameters studied in these ewes. It can be concluded from this study that when two stressors occur simultaneously, the total cost may have severe impact on biological function.  相似文献   
4.
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.  相似文献   
5.
A study was conducted to assess the effect of multiple stresses (thermal, nutritional, and walking stress) on the adaptive capability of Malpura ewes in terms of changes in physiological mechanisms and blood biochemical changes. The study was conducted for a period of 35 days covering two estrous cycles during summer season (April–May). The ewes were randomly allocated into two groups of 12 animals each, viz., GI (n?=?12; control) and GII (n?=?12; multiple stresses). GI ewes were maintained in the shed while GII ewes were subjected to multiple stresses. GI ewes were maintained in shed while GII ewes were subjected to heat stress by exposing them to 32–44 °C (average 42 °C) and RH of 12–26 % for 6 h from 10:00 to 16:00 h in natural environment. GI ewes were provided with ad libitum feeding while GII ewes were provided with restricted feed (30 % of intake of GI ewes) to induce nutritional stress. Further, GII ewes were subjected to walking stress by forcing them to walk 14 km in two spans between 9:00 and 10:30 h and 15:00 and 16:30 h. Blood collection was done at weekly intervals. Multiple stresses significantly (P?<?0.01) affected body weight, respiration rate, pulse rate, rectal temperature, sweating rate, tri-iodo-thyronine, thyroxine, cortisol, hemoglobin, packed cell volume, glucose, and total protein. The findings from this experiment provide useful information to understand the ideal nutrient requirement for these animals to adapt to such stresses in the semi-arid tropical environment without compromising production.  相似文献   
6.
Feed scarcity during hot summer months is one of the major predisposing factors for low reproductive efficiency of livestock reared in hot semiarid environment. A study was conducted to assess the effect of concentrate supplementation during summer months on growth, reproductive performance, and blood metabolites in Malpura ewes. Twenty adult Malpura ewes were used in the present study. The ewes were divided into two groups viz, group 1 (n?=?10; control) and group 2 (n?=?10; concentrate supplementation). The study was conducted for a period of 35 days covering two estrus cycles. In the first cycle, only PGF2α was given to all ewes, while in second cycle, all ewes were synchronized for estrus using progesterone-impregnated intravaginal sponges and pregnant mare serum gonadotropin. The animals were allowed for grazing for 8–10 h per day. Apart from grazing, group 2 ewes were supplemented with concentrate mixture at 1.5 % of body weight. Concentrate supplementation had significant influence on body weight, ADG, estrus percentage, estrus duration, onset of estrus, ovulation response, plasma glucose, total protein, and urea. The present study reveals that ewes supplemented with concentrate mixture at 1.5 % of body weights during summer season significantly influenced the growth and reproductive performance of Malpura ewes. Further, the study signifies the importance of providing additional feed supplementation to ewes kept grazing under the conditions of a hot, semiarid environment to improve their reproductive efficiency.  相似文献   
7.
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8.
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, T3 and T4 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.  相似文献   
9.
A study was conducted to assess comparatively the growth performance of three different indigenous goat breeds during exposure to summer heat stress. The primary objective of the study was to observe the heat stress impact on the growth performance based on the body weight changes, allometric measurements, growth hormone (GH) concentration and peripheral blood mononuclear cell (PBMC) Insulin‐like growth factor‐1 (IGF‐1) mRNA expression pattern during the summer season in comparison with the local breed (Osmanabadi). Thirty‐six ten‐month‐ to one‐year‐old female goats of Osmanabadi, Malabari and Salem Black breeds were randomly divided into six groups, OC (n = 6; Osmanabadi control), OHS (n = 6; Osmanabadi heat stress), MC (n = 6; Malabari control), MHS (n = 6; Malabari heat stress), SBC (n = 6; Salem Black control) and SBHS (n = 6; Salem Black heat stress). Body weight was recorded at weekly intervals, whereas other growth and allometric measurements and blood collection were carried out at fortnightly intervals. Breed factor significantly (p < .05) influenced only few growth variables such as body weight, body mass index (BMI) and body condition score (BCS). However, heat stress treatment significantly (p < .05) reduced all growth parameters expect BMI. Further, the heat stress significantly (p < .01) increased plasma GH concentration in goats with significantly higher (p < .05) concentration recorded in OHS. Among the stress groups, the lower (p < .05) PBMC IGF‐1 mRNA expression was recorded in OHS, while the higher (p < .05) expression was observed in SBHS indicating the extreme adaptive capability of Salem Black breed. Thus, the results indicated that the Salem Black breed performed much better compared to both Osmanabadi and Malabari breeds indicating the superior ability of this breed to adapt to heat stress challenges. The results also indicated that plasma GH and IGF‐1 gene may act as ideal biomarkers for assessing the heat stress impact on growth performance in indigenous goats.  相似文献   
10.
This study was conducted to evaluate the effect of mineral and antioxidant supplementation on growth, reproductive performance and physiological adaptability of heat‐stressed Malpura ewes. The study was conducted for a period of 21 days in 21 adult Malpura ewes. The ewes were randomly divided into three groups with seven animals each viz. GI (control; n = 7), GII (heat stress; n = 7) and GIII (heat stress + mineral and antioxidant supplementation; n = 7). The animals were stall fed ad libitum with the diet consisting of 70% roughage and 30% concentrate. GI ewes were maintained under normal controlled condition in the shed, while GII and GIII ewes were subjected to heat stress by exposing them to 42 °C in the climatic chamber. The parameters studied were feed intake (FI), water intake (WI), body weight, body condition score (BCS), physiological, biochemical and endocrine responses. Heat stress significantly altered FI, water intake, BCS, respiration rate and rectal temperature in the afternoon, oestrus duration, estradiol, progesterone, Hb, PCV, plasma glucose, total protein, cortisol, T3 and T4 levels while mineral and antioxidant supplementation ameliorated this heat stress effect on the parameters studied. Further, the adverse effect of heat stress on the productive and reproductive efficiency of Malpura ewes was reduced considerably by mineral mixture and antioxidant supplementation. This is evident from the non‐significant difference in BCS, oestrus duration and plasma estradiol between GI and GIII in this study. Hence, it is very pertinent to conclude from this study that mineral mixture and antioxidant supplementation were able to protect Malpura ewes against heat stress.  相似文献   
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