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

N-Acetylcysteine assists muscle development in offspring of mice subjected to maternal heat stress during pregnancy

BACKGROUND

Heat stress (HS) has been shown to affect reproductive performance and muscle development negatively in animals. N-Acetylcysteine (NAC) plays a pivotal role in enhancing the antioxidant performance in animals as a recognized antioxidant. The present study assesses the potential of NAC to modulate the reproductive performance and antioxidant function in pregnant mice exposed to HS. The role of NAC in muscle development of offspring mice was also explored.

RESULTS

The results showed that NAC supplementation from day 12 to day 18 of gestation increased the number of litters and enhanced the antioxidant function in pregnant mice under HS exposure. It improved the weight and body condition significantly in the offspring mice (P < 0.05). The alleviation of HS-induced muscle impairment with NAC was consistent with the alleviation of apoptosis, the enrichment of the proliferation and differentiation in the offspring mice muscle. N-Acetylcysteine also reversed HS-induced reduction in the cross-sectional area of the leg muscle and increased the proportion of myosin heavy chain IIx (MYHCIIx) in the muscle fiber.

CONCLUSION

The results of the present study support the use of NAC at a dose of 100 mg kg-1 body weight as supplement for protecting the offspring derived from pregnant mice exposed to HS from muscle impairment by accelerating proliferation and differentiation. © 2024 Society of Chemical Industry.

Heat stress adaptation in cows - Physiological responses and underlying molecular mechanisms

Heat stress is a key abiotic stressor for dairy production in the tropics which is further compounded by the ongoing climate change. Heat stress not only adversely impacts the production and welfare of dairy cows but severely impacts the economics of dairying due to production losses and increased cost of rearing. Over the years, selection has ensured development of high producing breeds, however, the thermotolerance ability of animals has been largely overlooked. In the past decade, the ill effects of climate change have made it pertinent to rethink the selection strategies to opt for climate resilient breeds, to ensure optimum production and reproduction. This has led to renewed interest in evaluation of the impacts of heat stress on cows and the underlying mechanisms that results in their acclimatization and adaptation to varied thermal ambience. The understanding of heat stress and associated responses at various level of animal is crucial to device amelioration strategies to secure optimum production and welfare of cows. With this review, an effort has been made to provide an overview on temperature humidity index as an important indicator of heat stress, general effect of heat stress in dairy cows, and impact of heat stress and subsequent response at physiological, haematological, molecular and genetic level of dairy cows.

Influence of body condition score during late pregnancy on the variations of biochemical parameters and lamb stillbirths in Rembi ewes

The transition period in ewes is associated with a lot of changes, such as metabolic disorder due to the mobilization of body reserves, behavior trouble, food intake, and some changes in body condition score (BCS). This knowledge led us to hypothesize the influence of BCS in ewes during late pregnancy on the variations of biochemical parameters and its influence on the survival of lambs. In order to assess how BCS affected changes in biochemical parameters and lamb stillbirth, blood samples were collected in heparin tubes from forty-nine randomly chosen ewes of the Rembi breed that were clinically healthy and at the end of their pregnancies. The results showed that glucose (Glu) and urea values were highly influenced by the BCS (P < 0.001), while cholesterol (CHL) and gamma-glutamyl transferase (GGT) were significantly influenced by the BCS (P 0.05). We also noted a highly significant decrease (P < 0.001) in the concentration of plasma of Glu and CHL in ewes with BCS = 4 compared to those with BCS = 2, recording a negative correlation (Glu and BCS, r =  - 0.52; P = 0.0001) and (CHL and BCS, r =  - 0.36; P = 0.009). In contrary, serum urea values were highly increased in ewes with BCS = 4 compared to those with BCS = 2 with a positive correlation (urea and BCS, r = 0.72; P = 0.001). On the other hand, the highest rate of lamb mortality was recorded in ewes with BCS = 4 compared to those who had a BCS = 2 with a significant difference (P < 0.05). During late pregnancy, poor body condition or obesity of ewes were predisposing factors for metabolic disease and lamb stillbirths, which can cause significant economic losses.

Effects of the Level and Composition of Concentrate Supplements before Breeding and in Early Gestation on Production of Different Hair Sheep Breeds

Female hair sheep, 27 Dorper (DOR), 41 Katahdin (KAT), and 39 St. Croix (STC), were used to determine influences of the nutritional plane before breeding and in early gestation on feed intake, body weight, body condition score, body mass indexes, blood constituent concentrations, and reproductive performance. There were 35 multiparous and 72 primiparous sheep, with initial ages of 5.6 ± 0.25 years and 1.5 ± 0.01 years, respectively (average overall initial age of 2.8 ± 0.20 years). Wheat straw (4% crude protein; dry matter [DM] basis) was consumed ad libitum and supplemented with approximately 0.15% initial body weight (BW) of soybean meal (LS) or a 1:3 mixture of soybean meal and rolled corn at 1% BW (HS; DM). The supplementation period was 162 days, with the breeding of animals in two sets sequentially, with the pre-breeding period 84 and 97 days, and that after breeding began at 78 and 65 days, respectively. Wheat straw DM intake (1.75, 1.30, 1.57, 1.15, 1.80, and 1.38% BW; SEM = 0.112) was lower (p < 0.05), but average daily gain (-46, 42, -44, 70, -47, and 51 g for DOR-LS, DOR-HS, KAT-LS, KAT-HS, STC-LS, and STC-HS, respectively; SEM = 7.3) was greater (p < 0.05) for HS than LS treatment during the supplementation period. Additionally, changes in body condition score during the supplementation period (-0.61, 0.36, -0.53, 0.27, -0.39, and -0.18; SEM = 0.058), and changes in body mass index based on height at the withers and body length from the point of the shoulder to the pin bone (BW/[height × length], g/cm²) from 7 days before supplementation (day -7) to day 162 were -1.99, 0.07, -2.19, -0.55, -2.39, and 0.17 for DOR-LS, DOR-HS, KAT-LS, KAT-HS, STC-LS, and STC-HS, respectively; (SEM = 0.297) were affected by supplement treatment. All blood constituent concentrations and characteristics addressed varied with the day of sampling (-7, 14, 49, 73, and 162) as well as the interaction between the supplement treatment and the day (p < 0.05), with few effects of interactions involving breed. Birth rate (66.7, 93.5, 84.6, 95.5, 82.8, and 100.0; SEM = 9.83) and individual lamb birth weight (4.50, 4.61, 4.28, 3.98, 3.73, and 3.88 kg; SEM = 0.201) were not affected by supplement treatment (p = 0.063 and 0.787, respectively), although litter size (0.92, 1.21, 1.17, 1.86, 1.12, and 1.82; SEM = 0.221) and total litter birth weight (5.84, 5.74, 5.92, 7.52, 5.04, and 6.78 kg for DOR-LS, DOR-HS, KAT-LS, KAT-HS, STC-LS, and STC-HS, respectively; SEM = 0.529) were greater (p < 0.05) for HS than for LS. In conclusion, although there was some compensation in wheat straw intake for the different levels of supplementation, soybean meal given alone rather than with cereal grain adversely affected BW, BCS, BMI, and reproductive performance, the latter primarily through litter size but also via a trend for an effect on the birth rate. Hence, the supplementation of low-protein and high-fiber forage such as wheat straw should include a consideration of the inclusion of a feedstuff(s) high in energy in addition to nitrogen.

Effects of Nutritional Plane at Breeding on Feed Intake, Body Weight, Condition Score, Mass Indexes, and Chemical Composition, and Reproductive Performance of Hair Sheep

This study was conducted to assess effects of the nutritional plane before and during breeding on feed intake, body weight (BW) change, reproductive performance, body condition score (BCS), body mass indexes (BMI), and body composition of three breeds of hair sheep. Twenty-five Dorper, 27 Katahdin, and 33 St. Croix ewes were allocated to groups and treatments based on initial BW and age. Supplementation treatments were soybean meal fed at 0.16% BW (LS) and a mixture of 25% soybean meal and 75% ground corn given at 0.8% BW (HS; dry matter basis) for 88 to 102 days including 17 days after breeding. Wheat straw intake (% BW) was greater (p < 0.01) for LS than for HS. Average daily gain and BCS change were similar among breeds, but both were greater for HS vs. LS. Birth rate, litter size, total litter birth weight, gestation length, and number of services were similar among breeds (p > 0.05), although individual lamb birth weight was lower for St. Croix than for Katahdin (p < 0.05). None of these reproductive variables were influenced by treatment or the breed × treatment interaction (p > 0.05). There were no breed differences in whole body concentrations of water, fat, protein, ash, or energy in week 0 or 4, but in 8 week concentrations of water, protein, and ash were greatest among breeds for St. Croix (p < 0.05) and levels of fat and energy were lower for St. Croix than for Dorper (p < 0.05). In week 8, total amounts and concentrations of fat and energy were greater for HS vs. LS and those of water, protein, and ash were less for HS (p < 0.05). There were interactions (p < 0.05) between treatment and period in blood concentrations of cholesterol and non-esterified fatty acids and between breed, treatment, and period in level of triglycerides and total antioxidant capacity. The concentration of cortisol was greater for HS vs. LS (p < 0.05). In conclusion, supplementation did not influence reproductive performance despite differences in BW and BCS change, which may be due to the initial moderate BCS and greater wheat straw intake for the LS treatment.

Multifaceted Interplay among Social Dominance, Body Condition, Appetitive and Consummatory Sexual Behaviors, and Semen Quality in Dorper Rams during Out-Of-Season and Transition Periods

Dorper rams (n = 24) were evaluated during the sexual resting season to determine their social rank (SR), either high (HSR) or low (LSR), under intensive management conditions in northern Mexico (25° N). Aggressive behaviors were quantified during male-to-male interactions, and appetitive and consummatory sexual behaviors during male-to-female interactions. Morphometric, live weight (LW), and body condition score (BCS) were recorded. During the early reproductive season, male-to-female behaviors were newly itemized simultaneously by seminal quality and quantity sampling. Finally, the dependent variables of the hemogram components were also quantified. Neither LW (61.25 ± 2.4 kg) nor morphometric variables differed between SR groups. However, BCS (2.25 vs. 2.66 u), sexual behaviors (i.e., approaches: 59.6 vs. 21.73 n, mating with ejaculation: 77.7 vs. 42.86 %, latency to ejaculation: 16.6 vs. 143.07 s), ejaculate volume (0.57 vs. 0.23 mL), and hemogram components favored the HSR rams (p < 0.05). Moreover, in their first male-to-female interaction, >50% of the LSR rams failed to display any sexual activity. HSR rams displayed a greater number of threatening behaviors, managing to displace LSR rams when exposed to estrus ewes during the male sexual resting season; more sexual behaviors; and an increased seminal volume in a non-live weight-dependent fashion.

Reproductive Performance of Ewes, Fed Flushing Diet at Different Management Feeding Program

&lt;b&gt;Background and Objective:&lt;/b&gt; There is very rare information regarding data of reproduction performance of small ruminant with different management flushing program in Asian countries. The aim of this study was to evaluate the implementation of flushing diet program containing lemuru fish oil with time management difference, by evaluating the reproductive performance of local Garut ewes. &lt;b&gt;Materials and Methods:&lt;/b&gt; Twenty of garut ewes (average body weight 30.06±6.20 kg) were used in this experiment using Completely Randomized Block Design (CRBD), in four treatments with five animals of each treatment. The treatments were without flushing (F0 as control), flushing at the beginning of mating (F1 = 2 weeks pre-mating until 2 weeks just after-mating), two times flushing (F2 = F1 plus 4 weeks flushing during mid gestation) and three times flushing (F3 = F2 plus 2 weeks flushing at the end of gestation and 2 weeks after parturition). The ratio of flushing or basal concentrate to forage was 70:30. Basal concentrate was given during untreated. Nutrients consumption, body condition score (BCS), average daily gain (ADG), feed efficiency ratio (FER) and reproduction parameters were evaluated. The data of sex ratio and birth type were expressed descriptively. &lt;b&gt;Results:&lt;/b&gt; The results showed that the treatment had significant effect (p<0.05) on crude fat consumption, total digestible nutrients (TDN) and changes of BCS values, but had no effect on other nutrients consumptions. All treatments did not affect to total birth weight, the number of embryo, litter size, gestation period and sex ratio. The percentage of ewes pregnancy with the flushing treatment was 25% higher than the control. The flushing treatments were significantly effect on partus weight of ewes (p<0.05). &lt;b&gt;Conclusion:&lt;/b&gt; It was concluded that three times flushing program at early, middle and late of gestation could improve the nutritional status and reproductive performance of ewes, such as fat intake, partus weight, improved percentage of pregnancy and type of birth, but did not affect to total birth weight, litter size, pregnant period and sex ratio.

Effects of fossil shell flour supplementation on heat tolerance of dohne merino rams

This study evaluated the effects of fossil shell flour (FSF) supplementation on heat tolerance of Dohne Merino sheep. Twenty-four (n = 24) Dohne Merino rams of about 4 months old, weighing 22.3 ± 0.43 kg were confined in individual pens using complete randomized design for a period of 100 days. The rams were subjected to four varying inclusion levels of fossil shell flour (0 g/kg, 20 g/kg, 40 g/kg and 60 g/kg. Water and feed intake were recorded throughout the period of successive feeding. On days 0, 45 and 90, blood samples were collected for analyses. The parameters monitored included the average daily water intake (ADWI), average feed intake (ADFI), skin temperature (ST), respiration rate (RR), pulse rate (PR), rectal temperature (RT), total plasma protein (TPP), blood glucose (GLU), red blood cell (RBC),white blood cell (WBC), Heamaglobin (Hb), mean corpuscular hemoglobin concentration (MCHC), Packed cell volume (PCV), and mean corpuscular volume (MCV). The inclusion levels of FSF affected ADWI and ADFI, revealing high water intake and feed intake in rams subjected to 40 g/kg of FSF followed by 60 g FSF/kg, 20 g FSF/kg and 0 g FSF/kg (P< 0.01) respectively. All the physiological parameters (ST, RT, RR and PR) decreased with increase in inclusion levels of FSF (P< 0.01). The TPP and GLU increased as the levels of FSF increases (P< 0.01). The RBC and WBC were higher in rams subjected to FSF supplemented diets compared to the control (p<0.05). We conclude that water and feed intake increase with increasing levels of the FSF while the physiological parameters decline as levels of FSF increases. Hence, fossil shell flour could be used as a supplement in Dohne-Merino rams’ diet to mitigate heat stress and promote overall productivity of the sheep.

Dietary nutrient restrictions in the post-weaning period change feed efficiency and productivity of Santa Inês ewe lambs

Context Interest in sheep production has grown considerably, mainly in the meat market segment in large urban centres. This growth is due to improved efficiencyand quality products, which makes the segment attractive for production. Aims Our objective was to evaluate the effects of dietary nutrient restrictions on the feed efficiency and productivity of Santa Inês ewe lambs. Methods Twenty Santa Inês ewe lambs were weaned at an average weight of 15.09 ± 2.63 kg and were randomly assigned in a 2 × 2 factorial design to nutritional plans for carcass finishing (early and late maturity) and levels of nutrient restriction (0% and 15% reduction of both crude protein (CP) and total digestible nutrients (TDN) relative to requirements) with five replications per treatment. The trial was divided into two phases: lambs aged 4–8 months (&lt;8 months) and lambs &gt;8 months old. Key results There were no differences (P &gt; 0.05) between diets for average daily gain (ADG), dry matter intake (DMI), feed efficiency and residual feed intake. Ratios of ADG:DMI (% of liveweight (LW) and LW0.75) were affected (P ≤ 0.05) by restriction in ewe lambs &gt;8 months old. Restriction model tests (ω1, ω2, ω3 and ω4) did not differ (P &gt; 0.05) from complete models for diets formulated for early maturity; therefore, a single standard growth curve fitted this nutritional plan. On the other hand, the restriction model responses for diets formulated to late maturity differed (P ≤ 0.05) from the complete model, generating different standard growth curves according to the applied restriction. Feeding Santa Inês ewe lambs a restricted diet (by 15% CP and TDN) in an early-maturity nutritional plan will allow lambs to reach slaughter LW earlier than those fed unrestricted diets. Conclusions and implications When the objective is to terminate animals at a later age (&gt;8 months), unrestricted diet formulated to a late-maturity nutritional plan will produce higher LW and subsequent reproductive efficiency. By contrast, reducing CP and TDN by 15% for ewe lambs &gt;8 months of age may reduce growth rates at an initial phase.

Improved early postnatal nutrition and its effect on histomorphological parameters in the testes of Sanjabi ram lambs

The effect of an ad libitum supplementary feeding on some reproductive characteristics of ram lambs were evaluated. Twelve Sanjabi rams were allocated to one of two groups: control (C) and treatment (T). The control group received hay and the treatment group received hay and concentrate with gross energy and crude protein concentration of 4.52 Mcal and 16% of dry matter, respectively. At the end of experiment, after taking blood samples for determination of testosterone concentration (TC), all lambs were castrated and the testicular weight (TWT), testicular volume (TV), testicular length (TL), and testicular width (TW) were measured. In addition, testes were subjected to histological analysis. Body weight (BW), TC, TWT, TL, and TV in the T group were higher (P < 0.05) than the C group. However, TW was not affected by diet (P > 0.05). Animals from the C group presented lower numbers (P < 0.05) of Sertoli (SCN), germ (GCN), and Leydig cell numbers (LCN) compared to the T group. Also, seminiferous tubule diameter (STD) in the T group was significantly greater than (P < 0.05) the C group. TWT had a significant association with TC (P < 0.05), STD (P < 0.01), SCN (P < 0.01), GCN (P < 0.05), and LCN (P < 0.05). TC was correlated with STD (P < 0.01), SCN (P < 0.01), GCN (P < 0.05), and LCN (P < 0.05). STD showed close correlation with SCN (P < 0.01), GCN (P < 0.01), and LCN (P < 0.05). Also, SCN had a positive association with GCN (P < 0.01) and LCN (P < 0.05). A positive correlation was found between GCN and LCN (P < 0.01). In conclusion, the plane of nutrition of growing ram lambs enhances their growth and testicular development and probably will increases their postpubertal reproductive performance.

Hair coat characteristics and thermophysiological stress response of Nguni and Boran cows raised under hot environmental conditions

Breed, age, coat colour, month and temperature humidity index (THI) influence on body weight (W), body condition score (BCS), thermophysiological variables (rectal temperature (Tr), skin temperature (Tsk)) and hair length was studied in Nguni (n = 19) and Boran (n = 16). As a result of this study, breed influenced W, BCS and Tsk on the neck and belly (P < 0.05). The BCS and W of Nguni cows were higher than the Boran cows. Hair length of both breeds increased from February to August. The THI influenced thermophysiological variables (P < 0.05). Increased Tr for both breeds was recorded in February and April, respectively (P < 0.05). Month influenced Tsk and June recorded lower values (P < 0.05). Younger cows (3-8 years) had lower weight and high Tr and Tsk (P < 0.05). Nguni cows had high neck and thurl temperatures in June while Boran cows had the highest in August (P < 0.05). Red, dun and white-black Boran cows had increased BCS. Nguni cows with red, fawn and white cows had high BCS. Fawn-coloured Nguni cows and white-brown Boran cows had the more weight than cows with other colours compared in the study. White-red Nguni and Boran cows recorded the highest Tr. For Nguni cows, neck and belly temperatures were significantly (P < 0.001) correlated to thurl temperature. Boran cows had significant (P < 0.001) correlations for THI and neck, belly and thurl temperatures. The current study found that Nguni cows were more adapted to the prevailing bioclimatic changes. However, Boran cows have the potential of performing well under heat stress conditions over time.

The potential interaction between ewe body condition score and nutrition during very late pregnancy and lactation on the performance of twin-bearing ewes and their lambs

Objective

The present study aimed to determine the impact of ewe body condition score (BCS) (over a range of 2.0 to 3.0) and nutritional treatments (consisting of differing herbage masses) during very late pregnancy and lactation and their potential interaction on the performance of twin-bearing ewes and their lambs to weaning.

Methods

On day 142 of pregnancy, twin-bearing ewes with a BCS of 2.0, 2.5, or 3.0 were allocated to a “Moderate’ or ‘Unrestricted’ nutritional treatment until day 95 of lactation (weaning). The nutritional treatments aimed to achieve average herbage masses of 1,200 to 1,300 kg dry matter (DM)/ha (Moderate) and 1,500 to 1,800 kg DM/ha (Unrestricted).

Results

There were no three-way interactions between ewe BCS group, nutritional treatment and time for any ewe or lamb parameter. The nutritional treatments had no effect (p>0.05) on lamb birth or weaning weight. Lambs born to Moderate ewes had greater survival and total litter weight at weaning (p<0.05). Regardless of BCS group, Unrestricted treatment ewes had greater body condition and back-fat depth at weaning than Moderate treatment ewes (p<0.05). Ewes of BCS 2.0 group reared lighter lambs to weaning (p<0.05) and tended to have a lower total litter weight (p = 0.06) than BCS 3.0 group ewes.

Conclusion

This study suggests farmers should aim to have all ewes with a BCS of 2.5 or 3 in late pregnancy for optimal lamb weaning performance. Furthermore, there is no benefit to lamb production of offering ewes pasture masses >1,200 kg DM/ha during very late pregnancy and lactation.

Effect of multiple stress factors (thermal, nutritional and pregnancy type) on adaptive capability of native ewes under semi-arid environment

This study was conducted to evaluate the effect of multiple stress factors (thermal, nutritional and pregnancy type) on two different native track breeds of ewes as reflected by their adaptive capability under semi-arid environment. The multiple stressor experiment was conducted in twenty-four ewes (12 Santa Inês and 12 Morada Nova ewes). Both heat stress and pregnancy stress was common to all four groups. However, the animals were divided into further two groups within each breed on the basis of nutrition regimen. According the groupings were: Group 1 (Six Santa Ines ewes; heat stress; nutrition at 0.5% of BW; single pregnancy); Group 2 (Six Santa Ines ewes; heat stress; nutrition at 1.5% BW; twin pregnancy); groups Group 3 (Six Morada Nova ewes; heat stress; nutrition at 0.5% of BW; single pregnancy); Group 4 (Six Morada Nova ewes; heat stress; nutrition at 1.5% BW; twin pregnancy). All the animals in the experiment were pregnant. Heat stress was induced by exposing all animals to summer heat stress in outside environment while the nutritional regimen followed was at 0.5% and 1.5% level of body weight (BW) respectively in each breed. The experiment was conducted in a completely randomized design with two breeds, two nutritional treatments and two pregnancy types, 10 repetitions for physiological parameters and six for blood parameters, with repeated measures over time. Physiological parameters (respiratory rate, pulse rate and rectal temperature) were measured with the animals at rest in the morning and afternoon, 0600-0700 and 1300-1400h, respectively, every seven days. Blood samples were collected every 14d for determination of serum glucose, triglycerides, cholesterol, urea and creatinine. We found interaction effect between breed and pregnancy type on respiratory rate and rectal temperature with greater values in Santa Inês ewes than Morada Nova ewes. However, there was no significant fixed effect of pregnancy type and supplementation level on physiological responses of breeds. Environmental factor (period of the day) had influenced the physiological responses of ewes during all gestational period. Santa Inês ewes had greater serum glucose concentration at 105d and 120d of gestation compared to the Morada Nova ewes. Morada Nova ewes had greater concentrations of triglycerides, urea at 120d, 150d and also greater cholesterol at 105d, 135d and 150d of gestation compared with Santa Inês ewes. The present result indicates that thermal condition was most important factor that modified the physiological responses of ewes in a semi-arid tropical environment.

Effect of mineral mixture and antioxidant supplementation on growth, reproductive performance and adaptive capability of Malpura ewes subjected to heat stress

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.

Effect of multiple stresses on growth and adaptive capability of Malpura ewes under semi-arid tropical environment

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.

Effect of walking stress on growth, physiological adaptability and endocrine responses in Malpura ewes in a semi-arid tropical environment

Sheep in hot semi-arid environments are mostly reared using extensive systems. In addition to thermal stress and feed scarcity, the animals need to walk long distances for grazing in this ecological zone. A study was conducted to assess the effect of long-distance walking on adaptive capability in terms of physiological, biochemical and endocrine responses in Malpura ewes. Fourteen adult Malpura non-pregnant ewes weighing between 33 and 35 kg were used in the study. The ewes were randomly allocated into two groups of seven animals each: GI (n = 7; Control), and GII (n = 7; walking stress). The animals were stall-fed with a diet consisting of 70% roughage and 30% concentrate. Both GI and GII ewes had uniform access to feed and water. The walking stress group (GII) ewes were made to walk 14 km in two spans between 0900 and 1500 hours with 1 h 30 min for each span (7 km) of walking. The ewes subjected to walking stress (GII) were prevented from grazing by applying a face mask made of cotton thread. The study was conducted for a period of two estrous cycles (35 days) during the autumn season (October-November). Physiological responses were recorded twice daily at 0800 and 1400 hours at weekly intervals. Blood samples were collected from the jugular vein at weekly intervals to study the effects of walking stress on blood biochemical and endocrine parameters. The results indicate that walking stress had significant (P < 0.05) influence on body weight, average daily gain, respiration rate (RR), rectal temperature (RT), haemoglobin (Hb), packed cell volume (PCV), plasma glucose, calcium, phosphorus, aspartate amino transferase (AST), alanine amino transferase (ALT), tri-iodo-thyronine (T(3)), thyroxin (T(4)), and cortisol. However, walking stress did not influence the reproductive hormone levels. The significant changes in RR, RT, plasma cortisol, T(3) and T(4) show that Malpura ewes have the capability to adapt to long-distance walking, and that adrenal and thyroid gland hormones play a significant role in such adaptation.

Effect of multiple stresses (thermal, nutritional, and walking stress) on the reproductive performance of malpura ewes

A study was conducted to assess the effect of multiple stresses (thermal, nutritional, and walking stress) on the reproductive performance of Malpura ewes. 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 twelve animals each namely, GI (n=12; Control), and GII (n=1 2; Multiple stresses). GI ewes were maintained in the shed, while GII ewes were subjected to multiple stresses (thermal, nutritional, and walking stress). The estrus % differed significantly (P< 0.05) between the groups. Estrus duration also showed similar trend to that of estrus %. Both conception and lambing rate also differed significantly (P< 0.05) between the control and multiple-stress group. In addition plasma estradiol and progesterone also showed significant difference between the groups. The study proved the detrimental effects of multiple-stresses on various reproductive parameters studied. Hence it is very pertinent to conclude that when two or more than two stressors occur simultaneously, the total impact may be severe on reproductive functions of the animals.

Effect of body condition score at mating on the reproductive performance of Kivircik sheep under an extensive production system

The aim of this study was to determine the effects of the body condition score (BCS) of ewes before and during the mating season on their reproductive performance under an extensive production system. In this study, 240 Kivircik sheep from the flocks of two breeders were used for over a 2-year period. The flocks were fed under extensive conditions on natural pastures throughout the year. The ewes were synchronized in two different periods, one of which was 45 days before the other. Before the introduction of rams to the ewes, the ewes were weighed after measuring their BCS. Detailed records were kept for every flock in each year. We found significant effects of BCS on pregnancy rate, lambing rate (P < 0.05) and fecundity (P < 0.05). The BCS for the highest pregnancy, lambing rate, and fecundity was determined between 2.01 and 3.00, while the lowest rates for these traits were ≤ 1.50. The highest rates of the pregnancy rate, lambing rate, and fecundity and gestation productivity were 75.9%, 70.9%, 1.11 and 3.34 kg, respectively.

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.

Adaptability and growth of Malpura ewes subjected to thermal and nutritional stress

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.