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

The effect of climate index on growth values from birth to breeding in Akkaraman sheep

Under specific agroclimatic conditions, growth is an adaptability parameter resulting in reduced performance with decreasing animal comfort of a sheep breed. In this study, a total of 1011 lambs' live weights (LW) and average daily weight gains (ADG) in 16 different farms between 2018 and 2020 (birth to 18 months) were determined in Akkaraman herds raised in Çankırı Province of Turkey. Comprehensive Climate Index (CCI) was examined to determine the effect of climate. Thermal comfort limits in CCI values were classified as CCI-1.cold (≤ 5 ℃), CCI-2.comfort (5-25 ℃), and CCI-3.warm (≥ 25 ℃). The climatic values that all lambs examined were exposed to according to index value groups in periods from birth to 18 months of age were prepared daily. The lambs were exposed to comfort environment in the majority of the days in the MP0-3 (77.7%) and MP12-18 (50.1%) periods. The lambs mostly in the MP3-6 period (72.2%) were above the warm stress threshold, but in the MP6-12 period, 54.7% were above the cold stress threshold. Overall mean LW of lambs at birth, at 3, 6, 12, and 18 months were 4.29 kg, 35.1 kg, 39.1 kg, 45.4 kg, and 52.6 kg, while the ADG values between birth-3 months, 3-6 months, 6-12 months, and 12-18 months were 341.8 g, 54.5 g, 42.9 g, and 56.8 g respectively. Periodically, CCI values were realized as 10-15, 25-30, and 18-22 in the growth periods of 0-3, 3-6, and 12-18 months, respectively, and ADG values of the lambs were found to be similar within their own periods. However, when the CCI values of the lambs increase to 5 and above in the 06-12-month period, there is a decrease in their live weight. As a result, climatic index values did not have a negative effect on the growth and development values of lambs in cold conditions in general, but warm conditions affected the animals negatively.

Comparative assessment of growth performance of indigenous and cross-bred calves subjected to combined stressors (heat and nutritional)

This study evaluated the impact of combined stressors (heat and nutritional stresses) on the growth and adaptive capability of Sahiwal (SW) and Karan Fries (KF) calves during the summer season. Calves in each breed were randomly divided into four groups. In SW breed the groupings were as follows: SWC (n = 4; Sahiwal Control); SWHS (n = 4; Sahiwal Heat Stress); SWNS (n = 4; Sahiwal Nutritional Stress) and SWCS (n = 4; Sahiwal Combined Stresses). Likewise, in the KF breed, KFC (n = 4; Karan Fries Control); KFHS (n = 4; Karan Fries Heat Stress); KFNS (n = 4; Karan Fries Nutritional Stress), and KFCS (n = 4; Karan Fries Combined Stresses). Control (C) and Heat Stress (HS) calves were fed ad libitum while Nutritional Stress (NS) and Combined Stresses (CS) calves were fed restricted feed (50% of C calves of respective breed) to induce nutritional stress in both the breeds. SWHS, SWCS, KFHS, and KFCS were exposed to summer heat stress from 1000 to 1600 h. All growth and adaptation variables were recorded at fortnightly intervals. Respiration rate, pulse rate, and rectal temperature during the afternoon were significantly (P < 0.01) higher in the CS group in both breeds. Further, CS had significantly (P < 0.05) higher plasma growth hormone and cortisol levels. Insulin-like growth factor-1, Triiodothyronine, and Thyroxine levels significantly decreased (P < 0.05) in the CS group in both breeds. Interestingly, heat stress didn't affect SWHS and KFHS bodyweight, however, a significant (P < 0.05) decrease in body weight of SWCS and KFCS was observed when compared with C. Hepatic mRNA expression of growth hormone, insulin-like growth factor-1, and growth hormone receptor significantly (P < 0.05) varied when compared between C and CS groups in both the breeds. The overall magnitude of stress was more pronounced in KF compared to the SW breed. This study concludes that when two stressors occur concurrently, they may have a greater influence on the adaptive capability of calves. Further, SW had better tolerance levels than KF, confirming the indigenous breed's superiority over cross-bred.

Influence of Heat Stress on Body Temperatures Measured by Infrared Thermography, Blood Metabolic Parameters and Its Correlation in Sheep

The aim of this research is to examine the influence of heat stress (HS) on body temperature (BT) measured rectally (RT) or by infrared thermography (IRT) of the nose (NT), eye (ET), leg (LT) and abdominal (AT) regions in intensively and extensively breed sheep and to detect a correlation between body temperature and metabolic response in sheep. A total of 33 Wurttemberg × Sjenica Pramenka sheep breeds were examined, 17 ewes were from outdoors and 16 were from indoor housing systems during three experimental periods (thermoneutral period, severe HS and moderate HS). Sheep under HS have a higher BT, and the magnitude of BT measured by infrared thermography (IRT) was higher than RT. LT and AT showed positive linear correlations with the temperature-humidity index (THI), while other ways of measuring BT did not give statistically significant correlations. Sheep under HS showed higher cortisol, insulin, total protein, albumin, urea, creatinine, bilirubin, aspartate aminotransferase, alanine aminotransferase, gamma-glutamyl transferase, alkaline phosphatase, lactate dehydrogenase, creatine kinase and index of insulin resistance, with lower values of triiodothyronine (T3), thyroxine (T4), non-esterified fatty acids, beta-hydroxybutyrate (BHB), glucose, calcium, inorganic phosphates, magnesium and cholesterol. BT and metabolic response were different in the function of the housing method of sheep. LT and AT showed a significant correlation with almost all blood parameters, and the strongest connections were made with T3, T4, BHB and the revised quantitative insulin sensitivity check index of insulin resistance. The abdomen and legs are good thermal windows because LT and AT are good summative responses to external ambient THI and internal metabolic changes in sheep under heat stress.

Effect of Nutritional Flushing Using Long-Term Energy and Protein Supplementation on Growth Performance and Reproductive Parameters of Doyogena Ewes in Ethiopia

The objective of the study was to establish the effect of appropriate supplementation days (days -21 to +7) using four isonitrogenous (14.7% CP) diets balanced to provide low (Lo-ME) or high (Hi-ME) metabolizable energy on the body condition score (BCS), body weight (BW) change, and reproductive performances of sheep. Thirty-five Doyogena ewes (27.71 ± 2.87 kg, 2-5 years of age, BCS of 2.0-2.5) grazing on natural pasture were randomly assigned to supplementary treatments consisting of combinations of enset leaf (EL) and commercial concentrate (CC): T0 (control), T1 (250 g EL + 500 g CC: Lo-ME), T2 (400 g EL + 500 g CC; Hi-ME), T3 (500 g EL + 400 g CC; Hi-ME), and T4 (500 g EL + 250 g CC; Lo-ME). The estrous cycle was synchronized with one intramuscular injection, 5 mg PGF2α, prior to artificial insemination. The dry matter (DM) from the pasture provided 1.10-1.46 kg/day, which corresponds to the DM requirements of the ewes until late gestation. However, the pasture provided a protein content of 9.52%, which was insufficient for breeding, mid-gestation, and gestation, requiring minimums of 16.1%, 13.1%, and 14.8%, respectively. The pasture could only provide enough energy for breeding ewes with a BW of up to 30 kg. The energy provided by pasture was insufficient for ewes weighing > 30 kg at mid-gestation and gestation, providing 6.9-9.2 MJ/day, below the requirement of 11.92-16.32 MJ/day required for mid-gestation and gestation. The energy was not sufficient for large ewes weighing > 40 kg. Supplementary diets T1-T4 provided DM in the range of 1.7-2.29 kg/day. This was sufficient for AI, mid-gestation, and gestation phases. Dietary supplements increased (p < 0.01) BW during breeding and mid-gestation. During lambing, T2 and T3 increased BW (p < 0.05) compared to T4 and T1. T4 had a similar effect (p > 0.05) on BW during lambing. T1, T2, and T3 significantly increased BCS (p < 0.05). T2 and T3 increased (p < 0.05) BCS at mid-gestation, but only T2 significantly increased BCD (p < 0.05) during lambing. All dietary supplements resulted in a shorter (p < 0.05) time to the resumption of estrous and the length of estrous (p < 0.05). T1, T2, and T3 resulted in a stronger estrous response (p < 0.05). Dietary supplements enhanced (p < 0.05) the conception rate and fecundity rate. The conception rate was highest in T2 and T3 at 85.7% and 83.3%, respectively. T2 had the highest fecundity rate at 151.7% (p < 0.05). Dietary supplementation increased the rate of lambing (LR), litter size (LS), and weight of lambs at birth (LBW). The LR for treatments T2, T3, and T4 was 100% versus 66.7% in the control. T1 and T2 significantly increased (p < 0.05) LS, but T4 had a similar LS to the control. Dietary supplements T1, T3, and T4 tended to increase (p < 0.05) LBW, but T2 increased LBW significantly (p < 0.05). Supplementation (T2, T3) with 400 g enset + 500 g CC and 500 g enset + 400 g CC are promising feed supplements to increase the reproductive capacities of Doyogena ewes in Ethiopia. Energy is as important to ewe flushing as protein.

Influence of successive heat waves on the thermoregulatory responses of pregnant and non-pregnant ewes

The frequency of heat waves has increased over the last years, with an impact on animal production and health, including the death of animals. Therefore, the aim of this study was to evaluate the dynamics of thermoregulation and hormonal responses in non-pregnant and pregnant ewes exposed to successive heat waves. Twenty-four non-pregnant and 18 pregnant Santa Ines ewes with black coat color (live weight: 55 ± 9.03 kg; age: 60 months) were used. Weather variables such air temperature, relative humidity, and solar radiation were continuously recorded. The rectal and tympanic temperatures and respiratory rate were measured daily. Serum triiodothyronine (T3) and prolactin were evaluated during the heat wave and thermoneutral periods. The physiological variables were higher under the heat wave conditions and were related to the activation of the thermoregulatory system for maintaining homeothermy (P < 0.05). The core body temperature was higher during successive heat waves (P < 0.05), as was the tympanic temperature, which are both affected by changes in air temperature (P < 0.05). T3 and prolactin levels were not influenced by successive heat waves (P < 0.05) and rectal temperature and respiratory rate were highest in non-pregnant ewes (P < 0.05). Prolactin was not affected by temperature. The results indicate that the Santa Ines breed overcomes the thermal challenge during a heat wave without showing severe signs of thermal stress regardless of being pregnant or not.

Carcass traits and meat quality of lambs slaughtered during different seasonal conditions

This study was conducted to evaluate the effects of slaughtering feedlot Texel lambs during different climatic conditions on carcass and meat quality traits. Twenty castrated male Texel lambs (21.8 ± 0.62 kg) were distributed to two treatments according to the climatic conditions during the finishing period and at pre-slaughter: warm season (WS; mean temperature of 23.4 °C and 77.5% relative humidity) and cool season (CS; mean temperature of 14.9 °C and 79.5% relative humidity). During the pre-slaughter, thermal comfort was evaluated through the variables: respiratory frequency, rectal temperature, temperature of the ocular region, and temperature-humidity index (THI). After the finishing period, lambs were slaughtered, and carcass and meat quality traits were assessed. The THI values indicate that animals harvested in the WS spent 13 h of the day under potential thermal discomfort conditions in the week before slaughter and in the pre-slaughter period, whereas lambs harvested in the CS did not experience any thermal discomfort. Slaughter weight, carcass weight, carcass dressing, and backfat thickness were greater (P ≤ 0.03), whereas cooling losses were lower (P < 0.01) for lambs slaughtered in the CS. Moreover, thawing losses were lower (P < 0.01), whereas cooking losses were greater (P < 0.01) for lambs harvested in the CS. Lambs slaughtered in the CS also showed greater meat redness, yellowness, and chroma values (P < 0.05). Although carcass traits were affected by the greater thermal discomfort exposure, meat quality of lambs was less impacted by the climatic conditions at slaughter.

The effect of high temperature and humidity on milk yield in Ankole and crossbred cows

Tropical regions are characterized by high temperature and humidity across the year. At high values of temperature humidity index (THI), there is a risk of heat stress leading to lower milk yield. The objective of this study was to describe the effect of season and the effect of maximum daily THI on milk yield of that day in purebred Ankole and Ankole-Friesian, Ankole-Jersey and Ankole-Sahiwal crosses in a tropical climate. In total, 53,730 records of daily milk yield from 183 cows in Rwanda were analyzed. The results showed that THI had a negative effect on daily milk yield above a threshold, but the effect was small (− 0.11 kg milk/THI unit at most). Purebred Ankole cows had the lowest daily milk yield and the lowest threshold (THI mean 66), as compared to the crossbreds (THI mean 68–69). Ankole-Friesian had a steeper decline in daily milk yield above the threshold than Ankole. The crossbreds, especially Ankole-Friesian, had higher daily milk yield than purebred Ankole also at very high THI. The results indicate some differences between breed groups in the way of coping with a hot and humid climate and raise questions about dairy cows’ adaptation to such a climate.

Causes and Flock Level Risk Factors of Sheep and Goat Abortion in Three Agroecology Zones in Ethiopia

A cross-sectional survey was conducted to estimate the incidence of small ruminant abortion and identify its major causes and potential risk factors in goat and sheep flocks in three agroecology and production systems of Ethiopia. Information on pregnancy outcomes and management risk factors were collected for 299 goat and 242 sheep flocks. Blood samples were collected from 133 sheep and 90 goat flocks and tested for Coxiella burnetii, Brucella spp., Chlamydia abortus, and Toxoplasma gondii. A causal diagram outlined relationships between potential predictor variables and abortion in the flock. The effect of management and exposure to infectious causes on the number of abortions in the flock across agroecology was tested using zero-inflated negative binomial regression. Results showed that 142 (58.68%) goats and 53 (17.73%) sheep flocks reported abortions in the 12 months before the survey. The mean annual flock abortion percentages were 16.1% (±26.23) for does and 12.6% (±23.5) for ewes. Farmers perceived infectious diseases, extreme weather conditions, feed shortage, physical traumas, and plant poisoning as the most important causes of abortion. A higher proportion of abortion was recorded during the short rainy season (March to May) and start of the short dry and cold season (June to August) in the lowland mixed crop-livestock and pastoral agroecology and production system, respectively. Overall, 65.41% sheep and 92.22% goat flocks tested positive for one or more abortion causing agents, namely, C. burnetti, C. abortus, Brucella spp., and T. gondii; mixed infection was found in 31.58% sheep and 63.33% goat flocks. Spending the night in a traditional house and providing supplementary feed for pregnant dams were important management factors which significantly (p ≤ 0.05) decreased the risk of abortion by 2.63 and 4.55 times, respectively. However, the presence of other livestock species and dogs in the household and exposure of the flock to Brucella spp. or anyone of the four tested infectious agents significantly (p ≤ 0.05) increased the risk of abortion in sheep and goat flocks. In general, abortion is a challenge for small ruminant production in the study area especially in lowland agroecology and calls for improvement in husbandry practices, health care and biosecurity practices.

Influência da restrição alimentar e do estresse térmico sobre parâmetros fisiológicos em ovinos

RESUMO Objetivou-se avaliar as alterações fisiológicas de ovinos submetidos à restrição alimentar, expostos à radiação solar e à sombra. Dez borregas mestiças foram divididas igualmente em dois grupos: grupo radiação solar - GRS, animais expostos ao sol durante o dia; e grupo sombra - GS, animais alocados dentro de um galpão à sombra. Nos seis dias iniciais de experimento, os animais foram submetidos à restrição alimentar, com acesso apenas à água, já expostos ao sol ou à sombra. Nos seis dias subsequentes, foi ofertada dieta composta por ração e feno de alfafa (3%PV). Os parâmetros avaliados foram frequência respiratória (FR), temperatura retal (TR), β-hidroxibutirato (BHB), pH urinário, ingestão de matéria seca (IMS) e dados bioclimáticos (temperatura, umidade relativa do ar e índice de temperatura e umidade - ITU). A FR foi o parâmetro em que houve maior diferença significativa entre os grupos (p<0,05). O balanço energético negativo foi constatado em todos os animais (BHB>0,8mmol/L; pH<7,0). Ovelhas que sofrem restrição alimentar durante períodos de alta temperatura e umidade têm menor frequência respiratória e temperatura interna, independentemente de estar na sombra ou pleno sol. Porém, quando normalizado a oferta de alimento as ovelhas em pleno sol têm menor ingestão de matéria seca.

The Impact of Heat Load on Cattle

Heat stress and cold stress have a negative influence on cattle welfare and productivity. There have been some studies investigating the influence of cold stress on cattle, however the emphasis within this review is the influence of heat stress on cattle. The impact of hot weather on cattle is of increasing importance due to the changing global environment. Heat stress is a worldwide phenomenon that is associated with reduced animal productivity and welfare, particularly during the summer months. Animal responses to their thermal environment are extremely varied, however, it is clear that the thermal environment influences the health, productivity, and welfare of cattle. Whilst knowledge continues to be developed, managing livestock to reduce the negative impact of hot climatic conditions remains somewhat challenging. This review provides an overview of the impact of heat stress on production and reproduction in bovines.

Optimum wool harvest interval of angora rabbits under organised farm conditions in East China

The present study was conducted to evaluate the commercial lifespan and optimum wool harvest interval of Angora rabbits. One hundred shorn Angora rabbits were housed in an organised farm to describe the wool production curve. It showed that the optimum wool harvest interval was 75 d, when fibre length reached 55.0 mm. Wool production was lower from the 3^rd to the 6^th mo (young stage) than from 7^th to 28^th mo and rapidly decreased from 28^th to 31^st mo and was the lowest from 31^st to 33^rd mo of age. Feed intake-to-wool production ratio was higher from 3^rd to 4^th and from 7^th to 9^th mo of age than during the adult stage, and increased from 31^st to 33^rd mo of age. Daily weight gain was significantly higher from 3^rd to 4^th mo of age than in any other periods of the adult stage, and was negative from 23^rd to 33^rd mo of age. Therefore, the study reveals that the commercial lifespan of Angora rabbits was approximately 28 mo. Furthermore, wool production was higher in spring and winter than in autumn, and was the lowest in summer. Concomitantly, feed intake-to-wool production ratio was lower in spring than in autumn and winter, and was the highest in summer. Finally, daily weight gain was higher in spring and autumn than in winter, and was the lowest in summer. This indicates that wool production was depending on the season, and decreased significantly in summer. Moreover, the spring provided the best conditions for Angora rabbits.

Diurnal rhythms of heart and respiratory rates in donkeys of different age groups during the cold-dry and hot-dry seasons in a tropical savannah

The aim of this study was to determine the effect of season on diurnal rhythms of heart (HR) and respiratory rates (RespR) in the adult, yearling, and foal donkeys during the cold-dry and hot-dry seasons under natural light/dark cycle. The resting HR and RespR were recorded bihourly for 24 consecutive hours from 06:00 to 06:00 h (GMT +1) in 30, clinically healthy donkeys (10 adults,10 yearlings, and 10 foals). Dry-bulb temperature (DBT), relative humidity (RH), temperature-humidity index (THI) and wet-bulb globe temperature index (WBGT) inside the pen were recorded bihourly from 06:00 to 06:00 h. Values of DBT, THI, and WBGT obtained during the hot-dry season were significantly (P < 0.05) higher than corresponding values recorded during the cold-dry season. Application of single-cosinor procedure showed that HR and RespR exhibited daily rhythmicity in both seasons. The mesors of the HR in adult (41.51 ± 0.34 beats/min [bpm]), yearling (40.80 ± 0.43 bpm), and foal (47.55 ± 0.40 bpm) donkeys during the cold-dry season were significantly (P < 0.01) lower, compared to the corresponding values of 48.4 ± 0.40 bpm, 50.42 ± 0.52 bpm and 58.10 ± 0.50 bpm, respectively during the hot-dry season. The mesors of RespR in adult, yearling, and foal donkeys during the hot-dry season were higher (P < 0.05), when compared to the corresponding values recorded in the cold-dry season. The HR and RespR of foals were significantly (P < 0.05) higher than those of the adult and yearling donkeys. Amplitudes of HR and RespR were higher during the hot-dry season than the cold-dry season. In conclusion, seasonal changes affect diurnal rhythmicity of HR and RespR of adult, yearling, and foal donkeys during the cold-dry and hot-dry seasons. The HR and RespR of donkeys vary with age, with higher values in the foals than the adult and yearling donkeys in both seasons.

High systemic and testicular thermolytic efficiency during heat tolerance test reflects better semen quality in rams of tropical breeds

This study aimed to assess the capacity of Morada Nova (MN) and Santa Inês (SIN) rams to maintain body and testicular homeothermy under thermal challenge. For 5 days in the summer, 16 males (SIN = 7 and MN = 9) underwent a heat tolerance test, i.e., period 1-animals maintained in the shade (11 to 12 h); period 2-animals exposed to sunlight (12 to 13 h); and period 3-animals returned to the shade (13 to 14 h). The respiratory rate, heart rate, rectal temperature, and infrared surface temperatures (IRT) of the trunk, back, eyeball, and testicles were assessed in each period. The index of capacity of tolerance to insolation (ICTI), which indicates the animals' level of adaptability, was calculated for each animal. Semen quality and testicular parenchyma integrity were assessed before and after the thermal challenge. Statistical analyses were performed at 5% significance. In period 1, the variables had baseline values for both genotypes. In period 2, the variables involved in thermolysis significantly increased (P < 0.05), which matches a thermal discomfort situation. In period 3, the variables returned to baseline values and some values were lower than those in period 1. Semen quality and testicular parenchyma integrity suffered no negative effects with the thermal challenge. IRT ocular and IRT testicular were positively correlated (P < 0.05). It is concluded that MN and SIN rams had efficient thermolytic mechanisms that favor preserving gonadal functionality. The animals were considered resilient to a thermal challenge. In addition, infrared thermography was an efficient tool to verify body and testicular thermoregulation.

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.

Effect of season on physiological, biochemical, hormonal, and oxidative stress parameters of indigenous sheep

Aim:

This study was conducted to evaluate the impact of summer and winter season on physiological, biochemical, hormonal, and antioxidant parameters in Indigenous sheep.

Materials and Methods:

The research was carried out during summer and winter season. 8 adult apparently healthy female sheep (aged 2-4 years) of similar physiological status were selected. Daily ambient temperature and relative humidity were recorded to calculate the temperature-humidity index (THI). The THI value of summer and winter season were 82.55 and 59.36, respectively, which indicate extreme hot condition during summer season and extreme cold condition during winter season. Physiological parameters were recorded daily during the experimental periods. Blood samples were collected at weekly interval and analyzed for biochemical, hormonal, and antioxidant parameters. The results were analyzed using completely randomized design.

Results:

From data obtained in this study, we found that higher THI during summer have significant effect over various physiological, biochemical, hormonal, and enzymatic indices of indigenous sheep. The physiological response such as rectal temperature, respiration rate (RR), pulse rate (PR), and skin temperature (ST) was increased significantly. We also found a significant increase in some biochemical parameters such as blood urea nitrogen (BUN), uric acid, creatinine (Cr), alanine transaminase (ALT), aspartate transaminase (AST), sodium (Na), and potassium (K). The level of cortisol hormone and superoxide dismutase (SOD), glutathione peroxidase (GPx), and lipid peroxidase (LPO) antioxidants increased significantly during summer. Whereas, some parameters such as glucose, cholesterol, calcium (Ca), inorganic phosphorus (IP), triiodothyronine (T₃), and thyroxine (T₄) were decreased significantly during summer season.

Conclusion:

It was concluded that the THI is a sensitive indicator of heat stress and is impacted by ambient temperature more than the relative humidity in Indigenous sheep. Higher THI is associated with significant increase in RT, RR, PR, ST, BUN, uric acid, Cr, ALT, AST, Na, K, cortisol, SOD, GPx, and LPO and with a significant decrease in glucose, cholesterol, Ca, IP, T₃ and T₄.

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.

The influence of altitude and landforms on some biochemical and hematological parameters in Ouled Djellal ewes from arid area of South East Algeria

Aim:

This study was conducted on Ouled Djellal ewes in arid area of south-east Algeria in order to reveal the influence of altitude and landforms on some hematological and biochemical parameters.

Materials and Methods:

A total of 160 ewes having 3-5 years of age, multiparous, non-pregnant, non-lactating and reared in arid areas of South East Algeria were included. Blood samples were divided according to factors of altitude and landform (plain region at 150 m above sea level, tableland region at 600 m above sea level and mountain region at 1000 m above sea level). The whole blood was analyzed for hematology, and plasma samples for biochemical analysis.

Results:

The study found lowest glucose concentrations were detected in tableland region at 600 m. In plain region at 150 m, ewes had a higher (p<0.01) concentration of cholesterol and triglyceride. Furthermore, a higher concentration of total proteins (p<0.01) and urea (p<0.05) were detected in plain region at 150 m. The average blood creatinine concentration in mountain ewes at 1000 m and tableland ewes at 600 m were higher (p<0.05) that in plain ewes at 150 m. The highest calcium concentration was found at the altitude of 150 m and the lowest at the altitude of 1000 m (1.12±0.35 mmol/L vs. 0.52±0.03 mmol/L). Phosphorus levels were higher at altitudes of 150 m than at the altitude of 600 m and 1000 m (0.93±0.42 mmol/L vs. 0.68±0.54 mmol/L, 0.23±0.01 mmol/L). The highest hemoglobin concentration and value of hematocrit were detected in mountain ewes at the altitude of 1000 m (120.61 g/L, 40%) and the lowest at the altitude of 150 m (73.2 g/L, 31%) (p<0.001).

Conclusion:

We concluded that hematological and biochemical parameters in Ouled Djellel ewes reared in arid area may be affected by altitude and landforms.

Effects of road transportation or droving on the weight and metabolism of young bulls

This study evaluated the effects of the mode of transportation on weight and metabolism of young bulls, which are generally transported by two systems: droving and truck. This experiment consisted of two phases: transportation and refeeding and involved transportation by droving and truck. Fifty young Nellore bulls were separated in equal numbers in both groups, droving group and truck group. In the transportation phase, animals were moved, in a 640-km journey. The refeeding phase consisted of 84 days and commenced after the animals arrived at the fattening farm. The effect of the transportation system on animals' weight, metabolic hormones, and serum biochemistry was assessed after 28, 56, and 84 days. During the transportation phase, animals in the droving group lost 10.11 kg and animals in the truck group gained 13.1 kg. The truck group showed 20.5 kg of weight gain at the end of the refeeding phase. The highest triiodothyronine (T3) and thyroxine (T4) concentrations were observed on days 0 and 60 in the transportation phase in both droving and truck groups. The serum cortisol concentration was higher in the droving group than in the truck group on day 56 of the refeeding phase. The IGF-I concentrations were higher during the refeeding phase in the droving group than in the truck group. Our results showed that transportation by droving leads to increased weight loss and reduced further weight gain compared to transportation by truck and that serum concentrations of T4, cortisol, and insulin-like growth factor (IGF-I) hormones are altered by the transportation system.

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.