Heat Stress and Goat Welfare: Adaptation and Production Considerations

This review attempted to collate and synthesize information on goat welfare and production constraints during heat stress exposure. Among the farm animals, goats arguably are considered the best-suited animals to survive in tropical climates. Heat stress was found to negatively influence growth, milk and meat production and compromised the immune response, thereby significantly reducing goats’ welfare under extensive conditions and transportation. Although considered extremely adapted to tropical climates, their production can be compromised to cope with heat stress. Therefore, information on goat adaptation and production performance during heat exposure could help assess their welfare. Such information would be valuable as the farming communities are often struggling in their efforts to assess animal welfare, especially in tropical regions. Broadly three aspects must be considered to ensure appropriate welfare in goats, and these include (i) housing and environment; (ii) breeding and genetics and (iii) handling and transport. Apart from these, there are a few other negative welfare factors in goat rearing, which differ across the production system being followed. Such negative practices are predominant in extensive systems and include nutritional stress, limited supply of good quality water, climatic extremes, parasitic infestation and lameness, culminating in low production, reproduction and high mortality rates. Broadly two types of methodologies are available to assess welfare in goats in these systems: (i) animal-based measures include behavioral measurements, health and production records and disease symptoms; (ii) resources based and management-based measures include stocking density, manpower, housing conditions and health plans. Goat welfare could be assessed based on several indicators covering behavioral, physical, physiological and productive responses. The important indicators of goat welfare include agonistic behavior, vocalization, skin temperature, body condition score (BCS), hair coat conditions, rectal temperature, respiration rate, heart rate, sweating, reduced growth, reduced milk production and reduced reproductive efficiency. There are also different approaches available by which the welfare of goats could be assessed, such as naturalistic, functional and subjective approaches. Thus, assessing welfare in goats at every production stage is a prerequisite for ensuring appropriate production in this all-important species to guarantee optimum returns to the marginal and subsistence farmers

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OPINION PAPERClimate change causes unprecedented challenge to the entire development of livestock production system. Climate change will negatively impact the animal directly through elevated temperature and precipitation pattern variation and indirectly through the reduced quality and quantity of crop yield, water availability and increased disease outbreaks. Among the all climatic variables, heat stress is the most intriguing factor which affects livestock sector. Heat stress detrimentally affects the animal growth, production and reproduction, which culminates in severe economic loss to the livestock farmers. Among the various internal regulators, hypothalamic-pituitary-adrenal (HPA) axis play a primary role in streamlining the adaptive activities of heat stressed domestic livestock. Therefore, methodologies pertaining to measuring stress level are very crucial for studying animal adaptation and its associated mechanisms. The HPA axis activity is often measured by corticosteroid release as a means to evaluate stress and well-being in animals. Although, the sympatho adrenal medullary system also originates from HPA axis still its products epinephrine and nor-epinephrine are available only for a transient period of time. Therefore, stress levels are primarily measured by the changes associated with HPA axis and its end-product glucocorticoids, has traditionally been the primary means to make inferences about the stress response in animals. Hence, future research efforts are needed to study in depth the functionality associated with HPA axis at cellular and molecular level to establish the hidden intricacies of stress pathways. These efforts may yield suitable biological markers which may be useful in identifying livestock species with superior thermo-tolerance ability to heat stress. Hence, attempt has been made in this opinion paper to project to the readers the significance of HPA axis for having in-depth understanding of the stress pathways in livestock. These efforts are vital as the scientific community battles in its efforts to identify the most suitable breed specific for different agro-ecological zones.ICAR-NIAN

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Not AvailableA study was conducted to establish the impact of heat stress, nutritional stress and the combined effect of both stresses (heat and nutrition) on the expression of toll-like receptors (TLRs) genes in liver samples of Osmanabadi goats. Twenty-four adult male Osmanabadi goats (average body weight 16.0 kg) were divided into four equal groups of six each: control (C), heat stress (HS), nutritional stress (NS) and combined stress (CS). The study was conducted over a 45 day period. The C and HS goats had ad libitum access to their feed while NS and CS goats were restricted feed (30% intake of C) to induce nutritional stress. The HS and CS goats were exposed to solar radiation for six hours a day between 10:00 h–16:00 h to induce heat stress. The animals were slaughtered at the end of the study and their livers were sampled for different TLRs gene expression assay. Among the different TLRs studied, TLR1, TLR3, TLR6, TLR7, TLR8 and TLR10 mRNA expressions were significantly (P < 0.05) higher in HS group as compared to other groups (C, NS and CS). The significantly higher levels of TLR1, TLR3, TLR6, TLR7, TLR8 and TLR10 mRNA expression in HS groups indicated that, when nutrition is not compromised, heat stressed animals were able to maintain their immune functions against heat shock proteins. This suggests that improving nutrition during heat stress condition may be highly beneficial to maintaining the immune status against heat shock proteins of the goats. The higher expression of TLR8 and TLR10 in the HS group indicates that these two genes may act as the immunological markers of heat stress in goats.Not Availabl

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Not AvailableBackground and Objective: Climate change related heat and nutritional stress weakens the animal’s immune system and makes them more prone to diseases. Although this has been observed by various researchers, the impact of these stresses on immune gene expression and process of heat stress mediated immune suppression at molecular level has not been dealt in detail in goat. Hence, the study was conducted to establish the impact of heat stress, nutritional stress and combined stresses (heat and nutritional) on different spleen Toll Like Receptor (TLR) genes expression in Osmanabadi goats. Materials and Methods: Twenty four adult Osmanabadi male goats (average body weight 16.0 kg) were divided into four groups viz., C (n = 6, control), HS (n = 6, heat stress), NS (n = 6, nutritional stress) and CS (n = 6, combined stress). The study was conducted for a period of 45 days. The C and HS goats had ad libitum access to their feed while NS and CS goats were under restricted feed (30% intake of C bucks) to induce nutritional stress. The HS and CS goats were exposed to heat stress in outside environment for 6 h a day between 10:00-16:00 h to induce heat stress. The average minimum and maximum temperature and Relative Humidity (RH) during the study period were 27.23±3.46, 38.33±0.52 and 37.0±4.16, respectively. The animals were slaughtered and their spleen was collected for different TLR mRNA expression. The relative gene expression was calculated using the formula 2–ΔΔCT. The results were expressed in fold change as compared to untreated control (control = 1 fold). Results: The fold expression level of TLR 1, 2, 3, 6, 7, 8, 9 and 10 mRNA in spleen followed the same trend in the current study where comparatively higher expression was noticed in CS group. These different TLR mRNA expressions in CS group were of higher magnitude as compared to both HS and NS group goats. This shows the severity of environmental stresses when occurring simultaneously and the consequences on immune response were much more severe than the individual stress. Conclusion: The activated splenic innate immune functions in terms of different increased TLR expression during combined stress indicate the Osmanabadi goat’s adaptation and disease resistance mechanism under extreme environmental conditions.ICA

Impacts of heat stress on immune responses and oxidative stress in farm animals and nutritional strategies for amelioration

Heat stress is one of the greatest challenges for the global livestock industries as increased environmental temperature and humidity compromises animal production during summer leading to devastating economic consequences. Over the last 30 years, significant developments have been achieved in cooling and provision of shade and shelter to mitigate heat stress reducing some of the losses associated with heat stress in farm animals. However, the recent increase in the incidence of heat waves which are also becoming more severe and lasting longer, due to climate change, further accentuates the problem of heat stress. Economic losses associated with heat stress are both direct due to loss in production and animal life, and indirect due to poorer quality products as a result of poor animal health and welfare. Animal health is affected due to impaired immune responses and increased reactive oxygen species production and/or deficiency of antioxidants during heat stress leading to an imbalance between oxidant and antioxidants and resultant oxidative stress. Research over the last 20 years has achieved partial success in understanding the intricacies of heat stress impacts on oxidative stress and immune responses and developing interventions to ameliorate impacts of heat stress, improving immune responses and farm animal health. This paper reviews the body of knowledge on heat stress impacts on immune response in farm animals. The impacts of heat stress on both cell-mediated and humoral immune responses have been discussed identifying the shift in immune response from cell-mediated towards humoral response, thereby weakening the immune status of the animal. Both species and breed differences have been identified as influencing how heat stress impacts the immune status of farm animals. In addition, crosstalk signaling between the immune system and oxidative stress has been considered and the role of antioxidants as potential nutritional strategies to mitigate heat stress has been discussed

News Letter 2018 vol 2

News Letter of NIANP for the month from July to Dec 2018Not AvailableICAR-NIAN

News Letter 2018

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News Letter 2019 Vol 1

Not AvailableICAR-NIAN

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Not AvailableClimate change acts as a major threat to climate sensitive sectors such as agriculture and animal husbandry. This change in climate will be a greatest challenge to about 1.3 billion population who depends on animal husbandry as their livelihood. Heat stress is considered as one of the primary factors that imposes negative impacts on production and reproduction in farm animals. In addition, it also alters the immune functions of the animal and makes them susceptible to infectious diseases. Based on the duration of exposure, heat stress either enhances or suppresses the immune functions in farm animals. The stress signal acts mainly through hypothalamo-pituitary-adrenal (HPA) axis to modulate the immune response. Generally, it is considered that heat stress acts to shift the adaptive immune function from cell mediated to humoral immunity and thus weakens the animal immune function. Another aspect of this climatic change is the threat of emerging and re-emerging pathogens and disease vectors for which livestock needs fine-tuned immune system to fight against naïve pathogens. Thus, the heat stress-immune system interactions need to be studied thoroughly in order to introduce various management and nutritional strategies to alleviate the ill-effects of heat stress in farm animals.Not Availabl

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Not AvailableThe study is an attempt to elucidate the molecular mechanisms governing growth performance during heat stress in goats. The primary objective of the study was to establish the influence of heat stress on the expression patterns of different growth related genes in Malabari goats. The study was conducted for a period of 45 days in 12 Malabari goats randomly allocated into two groups: MC (n = 6; Malabari control) and MHS (n = 6; Malabari heat stress). At the end of study period, all 12 animals were slaughtered and their liver tissues were collected for gene expression and histopathological studies. The temperature-humidity-index (THI) inside the shed (74.9) proved that the animals were not stressed while in the outside environment (86.5) the animals were extremely distressed. The hepatic growth hormone (GH), growth hormone receptor (GHR), insulin-like growth factor-1 (IGF-1), leptin (LEP) and leptin receptor (LEPR) gene expression patterns were significantly (P < 0.05) lower in heat stress group as compared to the control group animals. In addition, negative correlation (P < 0.05) was also established between THI and all the growth related gene expression in the study. The hepatic histopathological section showed more fatty and degenerative changes (P < 0.05) in hepatocytes in MHS group as compared to MC group. The study offers the first thorough insight into the expression patterns of different growth related genes during heat stress exposure in goats. Further, the study established GH, GHR, IGF-1, LEP, LEPR genes to be the ideal markers to reflect growth potential in Malabari goats.ICAR-NIAN