Proposing a strategy based on body-thermal status to improve the welfare of heat-stressed and water-deprived goats (Capra hircus)

Objective

Despite the considerable body of research on the effects of heat stress coupled with water scarcity (either through restriction or deprivation) on goats, aimed at enhancing their welfare, there remains a notable gap in the literature regarding the subsequent period following water restoration, during which the cumulative impact is fully alleviated. In response to this gap, we propose a strategy grounded in the assessment of body-thermal status to improve the welfare of heat-stressed and water-deprived goats. Specifically, our strategy seeks to determine the minimally required recovery interval necessary to completely mitigate the residual effects of water deprivation endured for a duration of 72 hours.

Methods

Eight healthy Aardi bucks, aged 10 months and weighing 30 kg, were subjected to three distinct stages: euhydration, dehydration, and rehydration. Each stage spanned for 72 hours except for the rehydration stage, which was left unrestricted. Various meteorological, biophysiological, and thermophysiological measurements were subsequently recorded.

Results

Exposure of heat-stressed goats, as indicated by the temperature-humidity index values, to a 72 hours deprivation period resulted in noticeable (p<0.05) alterations in their biophysiological (daily feed intake, body weight, and feces water content) and thermophysiological responses (core, rectal, skin, and surface temperatures, respiratory and heart rates, internal, external, and total body-thermal gradients, heat tolerance and adaptability coefficients, heterothermial total body-heat storage, and total water conservation). Remarkably, our findings demonstrate that all assessed variables, whether measured or estimated, returned to their baseline euhydration levels within 10 days of commencing the rehydration phase.

Conclusion

In order to improve the welfare of heat-stressed and 72 hours water-deprived goats, it is imperative to allow a recovery period of no less than 10 days following the restoration of water access prior to initiating any subsequent experiments involving these animals. Such experiments, addressing these critical aspects, serve to advance our understanding of goat welfare and obviously hold promise for contributing to future food security and economic viability.

Applicability of thermography as a potential non-invasive technique to assess the body-thermal status of heat-stressed and water-deprived goats (Capra hircus)

To evaluate the use of infrared thermography to assess the thermal status of heat-stressed and water-deprived Capra hircus, full-body surface temperature (TS) and six other body-thermal variables [core, rectal (TR), and skin (TSK) temperatures, respiratory and heart rates, and total body-thermal gradient (core-to-ambient, BTG)] were measured after three days of euhydration (EU), dehydration (DE), and rehydration (RE). Results revealed that the combined effect of heat stress and water deprivation had affected all tested variables including the TS, and once these animals gained access to water in the RE stage variables returned to their EU levels. Moreover, there were positive correlations between TS and all variables with the exception of BTG. From these six variables, only three variables (i.e. the TR, TSK, and BTG) during the DE stage and two variables (i.e. the TSK and BTG) throughout the experimental stages showed higher constancy (R2 ≥ 0 75, P < 0 001; agreement intervals ±1 96 95 % CI) with TS. However, BTG appeared more closely correlated with TS, representing the body-thermal status more realistically than other variables. In effect, the mean and thresholds of the BTG were predicted using the recorded TS and were within 0.02 °C of original estimates. Collectively, these findings show that infrared thermography is appropriate for assessing body-thermal status, and thus the welfare, of these animals under the three conditions studied, and conclude that full-body TS can be a surrogate proxy for BTG in these animals. Further experiments are needed to adequately examine the reproducibility of these results under biometeorologically-simulated environments and natural habitats.

Effects of Rumex nervosus leaf powder supplementation on carcasses compositions, small intestine dimensions, breasts color quality, economic feasibility in broiler chickens

Carcass characteristics, product quality, and the conversion of feed into meat with higher performance and feasibility are important determinants of the profitability and sustainability of any poultry enterprise. The objective of this study was to investigate the potential effect of Rumex nervosus leaf powder (RNLP) on carcass composition, small intestine dimensions, breast color quality, and economic feasibility of Ross broiler chickens. A total of 122 broilers were randomly distributed evenly among 4 treatments (0, 1, 3, and 5 g RNLP/ kg diet, n = 5 replicates per treatment, with 6 broilers per replicate: 3 ♀ and 3 ♂). Performance and economic data were collected in each replicate during the experiment. One male bird from each replication was examined for other criteria on d 34. Results showed that broilers fed 3 g of RNLP had a higher eviscerated carcass weight and dressing percentage (P < 0.05) than the control. The RNLP-fed broilers had higher weights and thicknesses in the duodenum and jejunum of up to 5 g and in the ileum and overall small intestine of up to 3 g. Broilers fed the lowest levels of RNLP had the highest revenue and net gain and the lowest cost-benefit ratio compared with those fed the highest levels of RNLP. The results indicate that the addition of RNLP has a positive effect on carcass processing, the intestinal measurements, and profitability ratios of the broilers. The 1 g RNLP/kg feed is the recommended dose to increase productivity and economic profitability ratios per kilogram of meat.

Effects of Different Levels of Yucca Supplementation on Growth Rates, Metabolic Profiles, Fecal Odor Emissions, and Carcass Traits of Growing Lambs

Sixty male Awassi lambs were used to investigate the effects of dietary Yucca schidgera extract (YS) on the production, fecal and urinary odor emissions, and carcass traits of growing lambs fed complete pellets. Lambs were fed either a complete pelleted diet without yucca (control) or supplemented with 300 or 600 mg YS/kg dry matter (DM) during the 84-day experiment. The weights and feed consumption of the lambs were measured weekly. Blood samples were taken on days 1, 28, 58, and 84, and ruminal fluid samples were collected on day 70. On day 90, the odor emissions from feces and urine were measured. On day 84, 12 lambs were slaughtered for the evaluation of carcass and meat quality. The final values for bodyweight, bodyweight gain, and feed efficiency of lambs fed the YS₃₀₀ diet were 3.40%, 6.64%, and 6.17%, respectively, higher (p < 0.05) than those fed the YS₆₀₀ diet. Additionally, the percentage of dressing, myofibril fragmentation index, and ruminal isovalerate percentage of lambs treated with YS₆₀₀ were higher than those treated with YS₃₀₀. Compared with the control, the addition of yucca reduced odor emissions from feces and urine. In conclusion, dietary YS₃₀₀ had no additional benefits on growth rate, feed efficiency, and carcass traits, while dietary YS₆₀₀ improved fecal and urinary odors.

Using chrono-physiological management in form of shifting the feeding time has no advantage in goat kids exposed to experimentally induced heat stress

Despite the proven outcomes of implementing chrono-physiological management (CPM) in several animals to promote their production performance, studies on its usefulness in goats are lacking. Twelve healthy Aardi male goat kids (22.60±1.10kg body weight; 6 months of age) were randomly allocated into two groups (morning-fed at 09:00 h and evening-fed at 21:00 h). The physiological and productive advantage of CPM (in form of shifting feeding time) was investigated in both groups while exposed to experimentally induced heat stress for 42 days (daily ambient temperature was cycling from 25 to 45°C). Thermophysiological (rectal, skin, and coat temperatures as well as respiratory rate), blood biochemical (plasma level of albumin, glucose, triacylglycerol, and urea), and production performance (daily feed intake, average daily gain, and feed conversion ratio) measurements were all obtained throughout this period. Current findings collectively revealed that shifting feeding time from 09:00 to 21:00 h had no (P > 0.05) impact on the thermophysiological status and blood metabolites of heat stressed kids. Above all, evidences have indicated that shifting feeding time had failed (P > 0.05) to demonstrate any consequence on promoting growth in these kids, thereby suggesting that shifting feeding time under hot climatic conditions has no advantage in goats. In fact, implementation of such an approach might not to be encouraged for heat-adapted animals. Experiments using other CPM methods (such as simultaneous shift of both feeding time and lighting program) can be however of further interest.

Resilience of Lambs to Limited Water Availability without Compromising Their Production Performance

Water scarcity is a common phenomenon in arid and semi-arid regions, which could have tremendous effects on livestock production. This study aimed to determine the level of water restriction that lambs fed on a pelleted diet can tolerate without compromising their production performance. A total of 24 male Najdi lambs were housed individually and randomly allocated into three equal groups, namely ad libitum water intake, 33% water-intake restriction, and 67% water-intake restriction. Dry-matter intake, feed conversion ratio, and average daily gain were decreased (p < 0.05) with the increasing level of water restriction. Water restriction had also reduced (p < 0.05) nutrient digestibility. The water-conserving ability of the water-restricted lambs was manifested by the production of concentrated and lower (p < 0.05) quantities of urine and feces. Meanwhile, serum osmolality and concentrations of albumin, total protein, urea-N, glucose, and non-esterified fatty acids were increased (p < 0.05) with the increasing levels of water restriction. It is surprising that lambs subjected to 67% water restriction retained more (p < 0.05) nitrogen relative to intake and had better (p < 0.05) efficiency of nitrogen utilization. It was strongly evident that lambs could tolerate water-intake restriction of up to 33% without compromising their production performance.

Influence of dietary chromium yeast supplementation on apparent trace elements metabolism in growing camel (Camelus dromedarius) reared under hot summer conditions

This study aimed to evaluate the effect of dietary chromium (Cr) supplementation on the apparent metabolism of some trace elements in camel calves reared under hot summer conditions. The study was conducted on a total of 15 male camel calves (5-6 months old) reared under hot summer conditions for 12 weeks. The animals were housed individually under shelter and divided into three dietary treatment groups (diets supplemented with 0.0, 0.5, or 1.0 mg Cr/kg DM), five animals each. At the end of the study, a metabolic trial was conducted on all camels for the evaluation of trace elements metabolism. Cr excretion, absorption, and retention showed an increasing trend with the increasing level of dietary Cr supplementation. Dietary Cr supplementation at 0.5 mg Cr/kg DM to camel calves resulted in a significant (P < 0.05) increase in Cu and an increasing trend in Zn and Mn excretion via urine and feces. However, Fe retention increased significantly (P < 0.05) in camel calves fed on diet supplemented with Cr. Dietary Cr supplementation to camel calves resulted in an increasing trend of plasma Cr concentration, while plasma concentration of Cu and Zn tended to decrease and without any effect on plasma Fe concentration. The results of the present study suggests that care should be taken for the negative interaction of Cr with the utilization of other trace elements, in cases where Cr is supplemented to the diet as a feed additive to promote growth and immunity under hot climatic conditions.

Daily rhythms of physiological parameters in the dromedary camel under natural and laboratory conditions

Camels are well adapted to hot arid environments and can contribute significantly to the economy of developing countries in arid regions of the world. Full understanding of the physiology of camels requires understanding of the internal temporal order of the body, as reflected in daily or circadian rhythms. In the current study, we investigated the daily rhythmicity of 20 physiological variables in camels exposed to natural oscillations of ambient temperature in a desert environment and compared the daily temporal courses of the variables. We also studied the rhythm of core body temperature under experimental conditions with constant ambient temperature in the presence and absence of a light-dark cycle. The obtained results indicated that different physiological variables exhibit different degrees of daily rhythmicity and reach their daily peaks at different times of the day, starting with plasma cholesterol, which peaks 24min after midnight, and ending with plasma calcium, which peaks 3h before midnight. Furthermore, the rhythm of core body temperature persisted in the absence of environmental rhythmicity, thus confirming its endogenous nature. The observed delay in the acrophase of core body temperature rhythm under constant conditions suggests that the circadian period is longer than 24h. Further studies with more refined experimental manipulation of different variables are needed to fully elucidate the causal network of circadian rhythms in dromedary camels.

Subsequent influences of feeding intact green seaweed Ulva lactuca to growing lambs on the seminal and testicular characteristics in rams

The present experiment was designed to investigate the subsequent influences of supplementing different levels of intact green seaweed Ulva lactuca (0%, 3%, and 5% DM) to growing sexually immature lambs during the growth period (74 d) on the seminal and testicular characteristics of sexually mature rams. Ulva lactuca was manually collected, adequately prepared, and then incorporated into lambs' diets. Eighteen male 3-mo-old lambs of the Awassi breed with a mean BW of 22.57 kg (SD = 1.08) were randomly assigned into treatments. The obtained results indicate that offering Ulva lactuca at the level of 3% or 5% DM to lambs during the growth period had no subsequent impacts (P > 0.05) on liver and kidney functions as well as blood water balance in rams, thereby suggesting that Ulva lactuca can be safely supplemented to lambs during growing. However, our findings point out that feeding a lamb diet supplemented with intact Ulva lactuca failed to demonstrate any subsequent benefit (P > 0.05) on the growth performance, thermoregulatory responses, and plasma oxidative status in rams. Above all, it was clearly evident that supplementing intact Ulva lactuca to lambs had demonstrated subsequent negative influences (P < 0.05) on seminal and testicular characteristics of rams, more noticeably observed at the 5% DM inclusion rate than at 3%. These results were manifested by the inferior (P < 0.05) seminal quality, reduced (P < 0.05) testicular morphometry, changes (P < 0.05) in testicular histopathology, defective (P < 0.05) endocrine signaling, and increased (P < 0.05) seminal oxidative stress in rams fed diets supplemented with Ulva lactuca during the growth period compared to control rams. The deleterious impacts of feeding intact Ulva lactuca on spermatogenesis and germ cell loss were proven to be attributed to the dysfunction of Sertoli cells. Collectively, these results provide novel insights on the subsequent influences of dietary supplementation of intact Ulva lactuca to lambs. The consistent evidence of profound negative impacts on seminal and testicular characteristics as well as the resulting data of no improvement of subsequent growth, thermoregulation, and plasma oxidative status in rams prompts us to tentatively recommend the avoidance of feeding intact Ulva lactuca to lambs.

Improvement of growth and nitrogen utilization in sheep using sugar beet pulp treated with Trichoderma reesei or urea

Twenty-five intact Barki lambs with mean body weight of 24.81 ± 0.16 kg were used to investigate the effect of including in the diet sugar beet pulp (SBP) treated biologically with Trichoderma reesei or chemically with urea 4 % on nutrients digestibility, growth performance, nitrogen (N) utilization, and hematological and biochemical parameters. Two experiments were conducted. In the growth experiment, five lambs were randomly assigned to one of five dietary treatments. Lambs were offered isonitrogenous and isoenergetic concentrate feed mixture containing on dry matter basis 0 % SBP (D0), 50 % SBP (D1), 50 % SBP treated with 4 % urea (D2), 50 % SBP treated with T. reesei (D3), and 25 % SPB treated with 4 % urea plus 25 % SPB treated with T. reesei (D4). In the metabolism experiment, five rams were used in a 5 × 5 Latin square design and housed in metabolism crates for 21 days. The present study showed that inclusion of SBP at the level of 50 % (D1) negatively affected diet digestibility coefficients of crude protein, crude fiber, and ether extract, in addition to average daily gain, feed conversion, and N utilization. However, treatment of SBP with urea (D2), T. reesei (D3), or the combination (D4) of both had improved (P < 0.05) these parameters with superiority of D3. Despite the significant differences in the tested hematological and biochemical parameters of lambs fed on biologically or chemically treated SBP diets, their levels remained within the physiological ranges which could indicate that treated SBP did not have any adverse effect on lambs' health.