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

How does grazing pressure affect feed intake and behavior of livestock in a meadow steppe in northern China and their coupling relationship

Livestock feeding behavior and intake play a crucial role in influencing grassland health and productivity. A comprehensive investigation into livestock feeding behavior and intake can effectively elucidate the interactions and impacts of livestock and grasslands, providing scientific evidence and technical support for the formulation and implementation of sustainable grassland development strategies. Based on a long-term controlled grazing experiment platform conducted over 13 years, the feeding behavior and forage intake of cattle under different grazing intensities were observed and analyzed. Additionally, we used GPS sensors to study cattle grazing behavior trends. Using Mantel's test, we analyzed the relationship between cattle movement distance, forage intake, and environmental factors. The results demonstrated that cattle forage intake decreased with increasing grazing intensity. Forage intake peaked at the end of July and beginning of August, with the highest efficiency observed in August. Moreover, under light grazing intensity, cattle exhibited greater fluctuations in forage intake than those under moderate and heavy grazing intensity. Cattle movement levels increased with higher grazing intensity, and during the period of lush grass growth, cattle displayed significantly higher movement levels than during grass senescence. The accuracy of the behavior determination model based on cattle velocity ranged from 60 to 80 %. Using this model, we found that under heavy grazing conditions, cattle spent significantly more time roaming than under light and moderate grazing. Conversely, under light grazing conditions, cattle spent significantly more time feeding. A negative correlation was identified between cattle forage intake and movement distance. Cattle's forage intake was significantly positively correlated with grass height and grass biomass and significantly negatively correlated with stocking rate and movement distance. Thorough research on livestock feeding behavior and intake offers scientific evidence and technical support for formulating and implementing sustainable grassland development strategies.

Supplementation of Moringa oleifera leaf concentrate pellets on nutrient utilization, antioxidant status, and reproductive performance of prolific ewes during extreme summer months in semi-arid tropical conditions

A feeding trial was conducted for a period of 60 days during extreme summer months to observe the effect of supplementation of Moringa oleifera leaves containing concentrate pellets on nutrient utilization, antioxidant status, and reproductive performance in Avishaan ewes reared under semi-arid condition. Forty adult non-pregnant cyclic ewes (2-3 years, 31.8 ± 0.81 kg body weight) were selected and randomly allocated into 2 groups of 20 animals each, viz., G-I (control) and G-II (treatment). The ewes were grazed on natural pasture for 8 h, offered ad libitum Cenchrus ciliaris hay after grazing and concentrate pellets @ 300 g/animal/day. The ewes in G-I were offered conventional concentrate pellets, whereas G-II ewes were offered concentrate pellets containing 15% Moringa leaves. The mean temperature humidity index during the period of study was 27.5 ± 0.3 and 34.6 ± 0.4 at 0700 h and 1400 h, respectively, indicating severe heat stress. Nutrient intake and utilization were comparable between the two groups. The antioxidant status was higher in G-II ewes as the values of catalase, superoxide dismutase, and total antioxidant capacity were higher (P < 0.05) in G-II ewes compared to G-I. The conception rate was higher (100%) in G-II ewes than G-I ewes (70%). Multiple birth percentage was 77.8% in G-II ewes, and it was comparable with the herd average of Avishaan (74.7%). However, ewes in G-I group exhibited a marked decline in multiple birth percentage (28.6%) than the normal herd average. Hence, it can be concluded that inclusion of Moringa oleifera leaves in feeding of prolific Avishaan ewes improved their antioxidant status resulting in optimum reproductive performance during stressful summer months.

The Behaviour of Sheep around a Natural Waterway and Impact on Water Quality during Winter in New Zealand

Access of livestock, such as cattle, to waterways has been shown to be a cause of poor water quality due to pugging damage and excretion entering the water. In New Zealand, regulations require that cattle, deer, and pigs are excluded from accessing waterways, but there are no such requirements for sheep. The current study utilised 24 h video cameras, global positioning system units, and triaxial accelerometers to observe the interaction of Romney ewes (n = 40) with a natural waterway. Ewes were either restricted (week 1) or given access to a reticulated water trough (week 2). Proximity data showed that ewes spent more time within 3 m of the waterway when the trough was unrestricted than when restricted (14.1 ± 5.7 and 10.8 ± 5.1 min/ewe/day, respectively; p < 0.05). Ewes travelled shorter distances on the steeper areas of paddock than flatter areas. Similarly, ewes showed a spatial preference for the flat and low sloped areas of the paddock. Concentrations of suspended sediment and total phosphorus were higher during access to a reticulated water trough which coincided with the week with more rainy days. Phosphorus and E. coli concentrations in the stream water samples were the above recommended Australian and New Zealand Environment and Conservation Council water quality guidelines, especially after rainy days, but did not appear to be directly related to sheep activity. Overall, the results suggest that during winter, ewes interacted very little with the waterway and were thus unlikely to influence the levels of nutrient and pathogens in the waterway.

Bioclimatic Zoning for Sheep Farming through Geostatistical Modeling in the State of Pernambuco, Brazil

The Intergovernmental Panel on Climate Change (IPCC) has pointed out the high vulnerability of developing countries to climate change, which is expected to impact food and income security. Sheep farming is one of the main animal productions among the families located in the most vulnerable regions of the semiarid region of Pernambuco state, a Brazilian territory known for its high temperatures, low relative humidity, and high net solar radiation. Therefore, the objective of this study was to identify different regions of Pernambuco that may be more suitable for different breeds of sheep, based on non-parametric statistics and kriging maps of the temperature and humidity index (THI). THI values were determined based on mean annual temperature and wind speed extracted from the TerraClimate remote sensing database. Pernambuco state presented THI values ranging from 66 to 79, with the hair breeds having a high potential for exploitation in almost all territories, including the main meat-producing breeds. The East Friesian breed, a high milk producer, would be well suited to the Agreste mesoregion, a territory that, like the Pajeú and Moxotó microregions, also proved favorable for the introduction of three wool breeds (Suffolk, Poll Dorset, and Texel) known as major meat producers. The kriging maps of the THI values successfully allowed the identification of strategic development regions of Pernambuco state with high potential for sheep breeding.

Influence of meteorological elements on behavioral responses of gir cows and effects on milk quality

This study aimed to analyze the principal components of the meteorological variables, physiological and behavioral response of cows subjected to different cooling times and their influence on milk quality, in the dry and rainfall periods, and to establish multiple regression models for milk quality. The data used in the study came from an experiment conducted in the Agreste Region of Pernambuco. The pre-milking cooling time was 10, 20, 30 min. and the control (without cooling). Sixteen multiparous lactating Gir cows were selected. Data were analyzed by principal component analysis and a multiple regression analysis was applied to determine milk quality. There was a strong relationship between somatic cell count (SCC) and activity of the animal in the shade for dry, and lying for rainfall, with increased SCC in cow milk. It was possible to establish two multiple regression models to determine milk quality in dry and rainfall periods. According to the principal component analysis, the cooling time to meet the thermal requirement of the animals was 20 min., regardless of the season and milking shift.

Effect of environmental factors on estrus synchronization and artificial insemination success in farmers flock in sheep under semi-arid tropical region

Environmental cues in the different seasons might influence the estrus and lambing percentages. The present study was conducted to assess the effect of environmental factors on estrus synchronization (ES) and artificial insemination success in sheep. During the period from 2012 to 2017, a total of 1,197 ewes of Kheri and Malpura breeds of 34 farms originating from 10 villages were synchronized for estrus and then fixed-time artificial insemination (FTAI) was done. Oestrous synchronization was done by intravaginal progesterone sponges and eCG protocol. Fixed-time cervical insemination was performed 48 and 56 hr after sponge removal in ewes exhibiting estrus, using liquid chilled semen containing 100 million sperm per dose of Patanwadi/Malpura rams. Mean sunshine hours, maximum and minimum ambient temperatures, temperature amplitude, mean relative humidity (RH), temperature-humidity index (THI), mean temperature during sponge-in to sponge-out-12-day period, sponge-out and next day, AI day and AI to next 15 days have been calculated. The estrus response and lambing percentage were higher (p < .05) when ES and FTAI were done during hot-humid with rainfall season. Successful (p < .05) ES occur when the minimum temperature was higher in cold-humid season, and the sunshine hour was higher in hot-humid with scanty rainfall season during sponge-in to sponge-out period. The success of the lambing percentage was higher (p < .05) when maximum temperature, minimum temperature, mean temperature and THI was higher on the day of AI and the next 15-day period, irrespective of the season. The success of FTAI indicates the adaptability of the local breed to tolerate the harsh climate of the hot semi-arid region without much hindrance in lambing percentages.

Grazing Seasons and Stocking Rates Affects the Relationship between Herbage Traits of Alpine Meadow and Grazing Behaviors of Tibetan Sheep in the Qinghai-Tibetan Plateau

Simple Summary

The relationship between vegetation and grazing behavior of Tibetan sheep on the Qinghai–Tibetan Plateau (QTP) remains a major concern for pursuing the sustainable grazing management of grassland. Grazing behavior is the daily activity of grazing livestock, which can reflect the growth status of the pasture and the level of grassland health in the local pasture, as well as the nutritional needs of Tibetan sheep. We studied the relationship between the grazing behaviors of Tibetan sheep and the quantity and quality of forage in different seasons and different stocking rates. Our results showed that the grazing behavior of Tibetan sheep was greatly affected by the quantity and nutritional quality of the forage. These results may be helpful for local herders to evaluate the nutritional status of forage and condition of grassland degradation, so that appropriate measures can be taken to protect local pastures in advance.

Abstract

Under the combined effect of stocking rate and grazing season, it is very significant to ascertain whether there is a quantitative relationship between plant community characteristics, chemical composition of forage, and grazing behaviors of Tibetan sheep to better utilize native pasture in the northeast region of the Qinghai–Tibetan Plateau (QTP). The two consecutive year observation experiments on Tibetan sheep’s grazing behavior were conducted to evaluate the above-stated relationships between stocking rates of 8 sheep/ha and 16 sheep/ha stocking rates in the both the warm and cold seasons. The results demonstrated that at 8 sheep/ha or in the warm season, due to better forage quality, Tibetan sheep had higher herbage mass, forage crude protein (CP) concentration, CP intake, dry matter intake (DMI), and interval between feed boluses and total number of steps, as well as lower fiber concentration than that at 16 sheep/ha or in the cold season. Diurnal intake rate and walking velocity while intaking increased as both average daylight ambient temperature and relative humidity rose. Using the CP concentration, acid detergent fiber (ADF) concentration, neutral detergent fiber (NDF) concentration, and forage metabolic energy (ME) to predict grazing behavior yielded the best fit equation for Tibetan sheep. For local herdsmen to sustainably use the alpine meadow, 8 sheep/ha in the warm season should be considered as the better grazing condition for preventing grassland degradation.

Effect of drinking earthen pot water on physiological response and behavior of sheep under heat stress

Heat stress is a major limiting factor for animal welfare and sheep production. Traditionally in India, the villagers used to keep their drinking water in the earthen pot to make it cold during summer. The cold drinking water (24-28 °C) during summer gives a feeling of relief from the heat. Therefore, the present study was carried out to assess the effect of drinking earthen pot water on physiological response and behavior of sheep under heat stress for one month. For this purpose, eighteen Avishaan rams were selected from the experimental animal flock and they were equally divided into three groups; viz., control (CON), heat stress (HS) and heat stress with earthen pot water (HSC). The animals of HS and HSC were exposed to higher ambient temperatures to induce heat stress inside the psychometric chamber. The animals of CON and HS were provided with ad-libitum water of their ambient temperature whereas; HSC groups were provided with ad-libitum cold water (24-28 °C) earthen pot water. All the animals were offered with 400 gm concentrate mixture and ad-libitum Cenchrus hay. The bodyweight of HS rams was significantly reduced (P < 0.05) at the end of the experimental period as compared to their initial body weight. The total roughage and dry matter intake was significantly higher (P < 0.01) in HSC rams as compared to HS rams. The plasma thyroxine concentration was significantly lower (P < 0.05) in HSC as compared with HS group. The rumination time significantly reduced (P < 0.05) in HSC group. However, The blood biochemical did not differ among the groups. Therefore, it may be concluded that Avishaan rams have the ability to adapt to heat stress. Nevertheless, the availability of earthen pot cold drinking water under heat stress reduced their body weight loss, improves their metabolic activity and ultimately improves their welfare.

Dietary supplementation of menthol-rich bioactive lipid compounds alters circadian eating behaviour of sheep

Background

Plant bioactive lipid compounds (PBLC), commonly known as essential oils, are increasingly evaluated as feed additives in ruminants due to beneficial effects on animal performance and health; however, there is no study evaluating circadian eating behaviour in ruminants. Altered eating behaviour may be implicated in changes of feed intake in ruminants. Therefore, the present study investigated the influence of menthol-rich PBLC on circadian eating behaviour in 24 growing sheep that were equally divided into three treatments, control (without PBLC), a lower dose (80 mg/d) or a higher dose (160 mg/d) of PBLC. Daily doses of PBLC were supplied with 600 g/d of concentrates fed in three equal portions at 07:00, 11:00 and 15:00 h for 4 weeks, whereas, meadow hay was fed ad libitum.

Results

The eating behaviour recorded by an automatic transponder-operated feeding system revealed that daily eating time and feeder visits increased with increasing doses of PBLC. The circadian distribution of eating time and feeder visits (with 1-h resolution) was influenced by the treatment. Eating time during concentrate-offering hours and between concentrate-offering hours increased or tended to increase linearly with greater concentrations of PBLC. Feeder visits did not change significantly during concentrate-offering hours, but were greater in the PBLC groups compared with the control between concentrate-feeding hours. Average length of the longest meals (5th percentile) decreased due to PBLC feeding. Daily feed intake was greater in the PBLC groups than the control.

Conclusions

Menthol-rich PBLC in the applied dose range stimulate circadian eating behaviour, which cannot only be attributed to their presence during concentrate feeding hours, but persist during post-concentrate feeding hours.

Transcriptomic Analysis Provides Novel Insights into Heat Stress Responses in Sheep

Simple Summary

The general increase in global temperatures has meant that heat stress has become an increasingly significant problem for sheep. This has both direct and indirect impact on their physiological functions, productivity, and health of sheep. Sheep generally live in high-temperature environments; however, the genes and pathways that play regulatory roles in the heat stress responses of sheep remain unclear. In this study, we applied RNA-Seq technology to analyze liver tissues of sheep from heat-stressed and control groups, and screened genes and pathways related to sheep heat stress. This work provides a theoretical foundation for the breeding and production of heat-resistant sheep.

Abstract

With the intensified and large-scale development of sheep husbandry and global warming, sheep heat stress has become an increasingly important issue. However, little is known about the molecular mechanisms related to sheep responses to heat stress. In this study, transcriptomic analysis of liver tissues of sheep in the presence and absence of heat stress was conducted, with the goal of identifying genes and pathways related to regulation when under such stress. After a comparison with the sheep reference genome, 440,226,436 clean reads were obtained from eight libraries. A p-value ≤ 0.05 and fold change ≥ 2 were taken as thresholds for categorizing differentially expressed genes, of which 1137 were identified. The accuracy and reliability of the RNA-Seq results were confirmed by qRT-PCR. The identified differentially expressed genes were significantly associated with 419 GO terms and 51 KEGG pathways, which suggested their participation in biological processes such as response to stress, immunoreaction, and fat metabolism. This study’s results provide a comprehensive overview of sheep heat stress-induced transcriptional expression patterns, laying a foundation for further analysis of the molecular mechanisms of sheep heat stress.

The role of N6-methyladenosine RNA methylation in the heat stress response of sheep (Ovis aries)

With the intensive development of the sheep industry and increasing global temperatures, heat stress in sheep has become an increasingly severe and important issue in recent years. The level of N6-methyladenosine (m6A) RNA methylation changes in response to stress plays important roles in stress responses. However, the role of m6A in the heat stress response of sheep remains unclear. To explore this issue, we measured heat stress protein (HSP) expression, liver function indexes, m6A on RNA, m6A-related enzyme expression, and tissue damage in sheep that had been subjected to heat stress. At the transcriptome level, our results showed significant increases in m6A on RNA and increased mRNA levels of HSPs (HSP70, HSP90, and HSP110) and m6A-related enzymes [METTL3 (methyltransferase-like 3), METTL14 (methyltransferase-like 14), WTAP (wilms tumor 1-associated protein), FTO (fat mass and obesity-associated protein), ALKBH5 (alkB homologue 5), YTHDF1-3 (YTH domain family proteins), and YTHDC1-2 (YTH domain-containing proteins)] following heat stress. At the protein level, the expression of METTL3, YTHDF1-2, and YTHDC2 showed no significant differences following heat stress. However, in contrast to its mRNA level after heat stress, the protein expression of YTHDF3 was reduced, while the expression of HSPs (HSP70, HSP90, and HSP110), METTL14, WTAP, FTO, ALKBH5, YTHDF3, and YTHDC1 increased in line with their measured mRNA levels. Histological experiments revealed that heat stress caused varying degrees of damage to sheep liver tissue. Moreover, immunohistochemical staining indicated that the m6A-related enzymes were expressed in sheep hepatocytes, and differences in expression patterns were observed between the control and heat stress groups. In summary, differences in the level of m6A and the expression of m6A-related enzymes in the liver of sheep were observed after heat stress. This indicates that m6A is involved in the regulation of heat stress in sheep. Our findings provide a new avenue for studying the responses to heat stress in sheep.

Combined effect of heat and nutritional stress on superovulation of Malpura ewes in a semi-arid region

Sheep reared in hot semi-arid environments are generally exposed to heat and nutritional stress in some seasons of the year, which affects both production and reproduction. To assess the effect of high ambient temperature and feed scarcity on superovulation, 16 adult Malpura ewes were randomly divided into two groups of 8 animals each. G1 (control) was kept under a shed and offered a maintenance diet, and G2 (combined stress) was subjected to both nutritional (30% less of maintenance diet) and heat (38-44 °C for 6 h/day) stress. Ewes were superovulated without estrus synchronization by a combination of single injection of 200 IU eCG and 8 injections of FSH (Folltropin-V) at 12-h intervals in tapering doses of 5 mg/kg body weight, starting from the day 7 of natural estrus. eCG was given with the first injection and PGF2α (10 mg) was given with the second last FSH injection. G2 increased respiration rate and rectal temperature (P < 0.01), and blood urea level (P < 0.05), whereas it decreased average daily gain, plasma T4 concentration (P < 0.01) and body weight (P < 0.05). Plasma estradiol level was lower (P < 0.05) in G2 ewes as compared to control (G1) ewes. However, the number of ewes showed a superovulatory response (88 vs 66% ewes ≥ 3 corpus luteum), ovulation rate (8.75 vs 5.88) and embryo production (5.5 vs 3.9) decreased, and the number of large follicles (anovulation) increased (1.0 vs 2.14) in G2 ewes. G2 had a comparable effect on the superovulatory response compared to control ewes although physiological changes occurred as an adaptive mechanism to stress. Therefore, the well-adapted cyclic sheep of the semi-arid region may be used for superovulation despite the stressful condition of heat exposure and nutritional insufficiency.