Effect of heat stress on blood parameter, carcass and meat quality of Black Bengal goat

Effects of Heat Stress on Goat Production and Mitigating Strategies: A Review

Goats, versatile creatures selectively bred for various purposes, have become pivotal in shaping the socioeconomic landscape, particularly in rural and economically challenged areas. Their remarkable ability to withstand and adapt to extreme heat has proven invaluable, allowing them to flourish and reproduce in even the harshest climates on Earth. Goat farming has emerged as a reliable and sustainable solution for securing food resources. However, despite its significance, the goat-producing industry has received less attention than other ruminants. Despite goats' inherent resilience to heat, their productivity and reproductive performance suffer under high ambient temperatures, leading to heat stress. This presents a significant challenge for goat production, necessitating a comprehensive multidisciplinary approach to mitigating the adverse effects of heat stress. This review aims to explore the diverse impacts of heat stress on goats and propose effective measures to address the sector's challenges. By understanding and addressing these issues, we can enhance the resilience and sustainability of goat farming, ensuring its continued contribution to food security and socioeconomic development.

Effect of heat stress on blood biochemistry and energy metabolite of the Dazu black goats

The objective of this study was to determine the effects of heat stress (HS) on physiological, blood biochemical, and energy metabolism in Dazu black goats. Six wether adult Dazu black goats were subjected to 3 experimental periods: high HS (group H, temperature-humidity index [THI] > 88) for 15 d, moderate HS (group M, THI was 79-88) for 15 d, and no HS (group L, THI < 72) for 15 d. Rectal temperature (RT) and respiratory rate (RR) were determined on d 7 and 15 of each period, and blood samples were collected on d 15 of each period. All goats received glucose (GLU) tolerance test (GTT) and insulin (INS) tolerance test on d 7 and d 10 of each period. The results showed that HS decreased dry matter intake (DMI) and INS concentration (p < 0.05), and increased RT, RR, non-esterified fatty acid (NEFA), cortisol (COR), and total protein (TP) concentrations (p < 0.05). Compared to group L, the urea nitrogen (BUN) concentration increased and GLU concentration decreased in group H (p < 0.05). During the GTT, the area under the curve (AUC) of GLU concentrations increased by 12.26% (p > 0.05) and 40.78% (p < 0.05), and AUC of INS concentrations decreased by 26.04 and 14.41% (p < 0.05) in groups H and M compared to group L, respectively. The INS concentrations were not significant among the three groups (p > 0.05) during the ITT. A total of 60 differentially expressed metabolites were identified in response to groups H and M. In HS, changes in metabolites related to carbohydrate metabolism and glycolysis were identified (p < 0.05). The metabolites related to fatty acid β-oxidation accumulated, glycogenic and ketogenic amino acids were significantly increased, while glycerophospholipid metabolites were decreased in HS (p < 0.05). HS significantly increased 1-methylhistidine, creatinine, betaine, taurine, taurolithocholic acid, inosine, and hypoxanthine, while decreasing vitamin E in blood metabolites (p < 0.05). In summary, HS changed the metabolism of fat, protein, and energy, impaired GLU tolerance, and mainly increased amino acid metabolism to provide energy in Dazu black goats.

Growth, haemato-biochemical, hormonal and disease characteristics in Black Bengal goats: a review

The goats have been considered one of the noteworthy animals to provide food security and could promote socio-economic upliftment under challenging climatic scenarios in the coming decades, particularly in the tropics. Black Bengal goat (BBG) is one of the recognised native meat-type breeds of hot-humid tropics with distinguished characteristics, including superior-quality meat, excellent skin and high prolificacy. Smaller body mass, lower metabolic rate and efficient utilisation of high-fibre forages enable BBG to adapt to a wide range of harsh climates in the tropics. The BBG can maintain physiological homeostasis efficiently in terms of electrolyte profile, endocrine functions and haemato-biochemical traits in different life phases, including the gestation period, even in high-saline coastal areas of hot-humid tropics. Crossbreeding to improve its growth rate has been attempted, but the prolificacy has been decayed. This review is intended to attract global attention to the adaptive potentialities of Black Bengal goats in terms of growth and production, haemato-biochemical, endocrinological, salt tolerance and disease characteristics that could be an asset of climate-resilient agricultural farming.

Analysis of carcass traits and quantitative expression patterns of different meat quality governing genes during heat stress exposure in indigenous goats

A study was conducted to assess the impact of heat stress on various carcass traits, meat quality variables and gene expression patterns which governs meat quality in indigenous female Kodi Aadu breed. The study was conducted for 45 days in climate chamber with 12 animals randomly allocated into two groups of six animals each, KC (n = 6; Female; Control), KHS (n = 6; Female; heat stress). Majority of the major carcass traits and meat quality variables remained intact between KC and KHS groups. The myostatin (MSTN), calpain 1 (CAPN1) and Diacylglycerol Acyltransferase 1 (DGAT1) mRNA expression patterns were significantly (P < 0.01) lower in KHS group as compared to KC group. However, the calpain 2 (CAPN2), calpastatin (CAST) and Crytallin alpha (CRYA) mRNA expression patterns were significantly (P < 0.05) higher in KHS group. Thus, the study established that the major carcass traits and meat quality variables remained intact after heat stress exposure in female Kodi Aadu goats. Further, MSTN, HSP27, CRYA and HSP90 genes were identified as biomarkers for reflecting meat quality during heat stress exposure in female Kodi Aadu breed.

Impact of heat stress on the growth performance and retail meat quality of 2nd cross (Poll Dorset × (Border Leicester × Merino)) and Dorper lambs

The present study investigated the impact of heat stress and genetics on lamb growth performance and meat quality. Forty-eight Dorper and 2nd cross [Poll Dorset × (Border Leicester × Merino)] lambs (38--42 kg; 4-5 months old) were allocated to either thermoneutral [TN; 18-21 °C, 45-55% relative humidity (RH)], or heat stress (HS; 28 °C-38 °C, 40-60% RH) conditions in a 2 × 2 factorial design for 2 weeks. Compared with 2nd cross, Dorper lambs had a lower respiration rate (RR) and rectal temperature (RT), and exhibited less decline in body weight under HS. 2nd cross lambs showed a higher body weight gain than Dorpers under TN conditions. HS increased a* and chroma of the Longissimus thoracis et lumborum (LTL) from 2nd cross lambs over 10 days of display, but had no impact on Dorper LTL. In conclusion, Dorpers showed higher heat tolerance compared with 2nd cross lambs during the 2 weeks HS.

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.

Effect of slaughter age and post-mortem days on meat quality of longissimus and semimembranosus muscles of Boer goats

This study investigated the effects of age of animal and days post-mortem (PM) on meat quality of Boer goats. Twenty-four (24) wether Boer goats of two age groups (2YO group: 2 years old and 9MO: 6-9 months, with 12 animals/group) were slaughtered in a commercial processing plant. The pH@Temp18 was estimated to be above 6 in both age groups with higher (P < 0.01) values in 2YO goats. The PM storage for 14 days reduced the shear force in both age groups (P < 0.01). 2YO goat muscles (longissimus and semimembranosus) exhibited higher (P < 0.01) Thiobarbituric acid reactive substance values (TBARS), indicating increased lipid oxidation. Glycogen (P < 0.01) and lactate content (20 min post-slaughter) in longissimus of 9MO were lower compared to 2YO, and total muscle glycogen concentration was lower (P < 0.01) in both age groups below the threshold levels. Hence, as hypothesized, age and days PM proved to play crucial roles on Boer meat quality.

Performance of Black Bengal goat: a 50-year review

Black Bengal goat (BBG) is the most widely recognized legacy goat breed in Bangladesh. The breed is black in color yet likewise earthy, white, or dim colors additionally found. The breed has medium body size with grown-up weight 25-30 kg, little horns, short legs, and tight body structure. The BBG is one of the most compliant, all around adjusted, early maturing, prolific, productive, and tropical disease-resistant goat types of the world that produces incredible quality meat, milk, and skin. The breed is versatile in hot, moist, cruel, climatic conditions and flourishes well on a cacophonous dietary regimen from uncultivable decrepit grounds, residences, riversides, banks, sloping, and hilly territories where crop culture or dairy nourishing is inconceivable. In Bangladesh, the BBG is one of the main red meat-producing small ruminants which shares remarkable local interest during Eid-Ul-Adha, Eid-Ul-Fitr, wedding ceremony, birthday festival, circumcision, memorial programs, and other social celebrations with no social, cultural, and religious limitations. Being little in size, the BBG has been an amazing asset to advance supportable vocations for the negligible, little, and landless ranchers who rely upon free regular grazing lands for raising domesticated animals. Regardless of incredibly exceptional components and features, the production of BBG has not yet been popularized widely since meager consideration has been paid for improving their efficiency. Development of cutting edge hereditary, dietary, and health as well as disease control procedure and utilization of modern management frameworks may procure considerable changes in improving the overall performance of the BBG.

Impacts of heat stress on meat quality and strategies for amelioration: a review

During the summer, high ambient temperature and humidity cause economic loss to the global livestock industry via reduced livestock productivity and increased mortality. The problem of heat stress (HS) is likely to be exacerbated by global warming and climate change. Recent research has shown that HS not only leads to physiological and metabolic perturbations in live animals but can also affect carcass and meat quality characteristics plausibly by altering the rate and extent of postmortem muscle glycolysis and resultant pH. However, these impacts of HS are not consistent across species. Higher incidence of pale soft and exudative (PSE) meat has been reported in poultry. On the contrary, higher incidence of high ultimate pH and dark firm and dry (DFD) meat or no impacts of HS have been reported in sheep and cattle. With the limited data on HS impacts on meat quality of ruminants, it is difficult to explain the exact mechanisms driving these variable impacts. However, it is hypothesized that the severity and duration of HS may lead to variable impacts due to lack of opportunity to adapdate to acute heat exposure. Longer HS exposure may allow ruminants to adapdate to heat and may not record any negative impacts on meat quality. This paper reviews the recent research on impacts of HS on meat quality characteristics and identify the key areas of further research required to better understand these negative impacts to develop strategies for amelioration. In addition, some mitigation strategies of HS have also been discussed which include both managemental and nutritional interventions.

Meat quality traits of European quails reared under different conditions of temperature and air velocity

This study’s objective was to evaluate the influence of thermal environment and air velocity during the rearing phase on European quail meat quality traits. A total of 1,152 one-day-old European quail chicks were placed inside floor pens within environmental chambers. Each experimental period was approximately 5 wks, with birds slaughtered at 37 d of age. The experimental design consisted of a 2 × 4 factorial arrangement of treatments in completely randomized design with 2 air velocities (0 and 2 m/s) × 4 air temperatures (severe cold [SC], moderate cold, thermal comfort, and moderate heat [MH]). ANOVA, with air velocity and thermal environment as fixed effects, was performed to evaluate the effect of main factors and their interaction on meat quality traits, using the GLM procedure (SAS 9.4). Least square means of treatments effects were compared using Tukey’s test (α = 0.05). Lightness (L∗), redness (a∗), and yellowness (b∗), of quail meat were affected by thermal environment and air velocity (P < 0.05). Initial and final L∗ values were greater for MH (P < 0.05). Meat from birds subjected to 2 m/s air velocity had lower final L∗, but no velocity effect was noted for initial L∗. Quail meat from SC presented higher initial and final a∗ values compared with the other thermal environment groups (P ≤ 0.001). Final a∗ was affected by air velocity (P < 0.05). Initial and final b∗ values for meat from MH were greater, 13.8 and 15.2, respectively, differing from the other treatment environments (P < 0.05). However, air velocity did not influence b∗ values (P > 0.05). Interactions were not significant for pHu (P = 0.993). Thawing loss and shear force were affected by treatments (P < 0.05) but not ultimate pH, drip loss, or sarcomere length. This study demonstrates that thermal environments and air velocity affect quail meat quality traits. Further investigation is recommended to explore effects of air velocity and thermal environment on muscle proteolysis of quail meat quality.

Comparative assessment of growth performance of three different indigenous goat breeds exposed to summer heat stress

A study was conducted to assess comparatively the growth performance of three different indigenous goat breeds during exposure to summer heat stress. The primary objective of the study was to observe the heat stress impact on the growth performance based on the body weight changes, allometric measurements, growth hormone (GH) concentration and peripheral blood mononuclear cell (PBMC) Insulin-like growth factor-1 (IGF-1) mRNA expression pattern during the summer season in comparison with the local breed (Osmanabadi). Thirty-six ten-month- to one-year-old female goats of Osmanabadi, Malabari and Salem Black breeds were randomly divided into six groups, OC (n = 6; Osmanabadi control), OHS (n = 6; Osmanabadi heat stress), MC (n = 6; Malabari control), MHS (n = 6; Malabari heat stress), SBC (n = 6; Salem Black control) and SBHS (n = 6; Salem Black heat stress). Body weight was recorded at weekly intervals, whereas other growth and allometric measurements and blood collection were carried out at fortnightly intervals. Breed factor significantly (p < .05) influenced only few growth variables such as body weight, body mass index (BMI) and body condition score (BCS). However, heat stress treatment significantly (p < .05) reduced all growth parameters expect BMI. Further, the heat stress significantly (p < .01) increased plasma GH concentration in goats with significantly higher (p < .05) concentration recorded in OHS. Among the stress groups, the lower (p < .05) PBMC IGF-1 mRNA expression was recorded in OHS, while the higher (p < .05) expression was observed in SBHS indicating the extreme adaptive capability of Salem Black breed. Thus, the results indicated that the Salem Black breed performed much better compared to both Osmanabadi and Malabari breeds indicating the superior ability of this breed to adapt to heat stress challenges. The results also indicated that plasma GH and IGF-1 gene may act as ideal biomarkers for assessing the heat stress impact on growth performance in indigenous goats.

Comparative assessment of heat stress induced changes in carcass traits, plasma leptin profile and skeletal muscle myostatin and HSP70 gene expression patterns between indigenous Osmanabadi and Salem Black goat breeds

The primary objective of the study was to compare the impact of heat stress on meat production characteristics of Osmanabadi and Salem Black breed goats based on changes in carcass characteristics, meat quality attributes, plasma leptin concentration, skeletal muscle myostatin and heat shock protein 70 (HSP70) gene expression patterns. The goats were randomly distributed into four groups: OSC (n = 6; Osmanabadi Control), OSHS (n = 6; Osmanabadi Heat Stress), SBC (n = 6; Salem Black Control) and SBHS (n = 6; Salem Black Heat Stress). The animals were slaughtered at the end of the study and their meat characteristics were assessed. This study established the impact of heat stress on a wide variety of carcass and meat quality characteristics in OS and SB goat breeds. The results from the study also provided some crucial evidence for a better resilience capacity of Salem Black breed as compared to Osmanabadi goats in maintaining the meat production during heat stress. The study also established plasma leptin and HSP70 genes to be the ideal biomarkers to reflect the impact of heat stress on meat characteristics in indigenous goats.