Kalyan De

Effect of short-term seclusion of sheep on their welfare indicators

Abstract Separation from the group is a potent stressor for sheep and may have an adverse effect on animal welfare. Therefore, the present study was initiated to determine the effect of short‐term seclusion of sheep on their welfare indicators in terms of behavior and endocrine level. Sixteen ewes aged 3‐4 years were kept together for one month to form a group and get emotionally accustomed to each other. Thereafter, one individual ewe was daily separated from their group and kept in a separate shed to ward off their visual and tactile contact with other group mates. Thus, the 16 ewes of the group were separated from their group individually for 24 hours one after another for one time for each individual. It was found that the dry matter intake, water intake, and body weight were reduced significantly (P < 0.05) after isolation from the group. Respiration rate, pulse rate, and rectal temperature increased significantly (P < 0.05) after separation from the group. Cortisol, thyroxine, and triiodothyronine levels were elevated after separation from the pen mate. The total time spent feeding, ruminating, and lying decreased significantly (P < 005), whereas standing and location time increased significantly (P < 0.05) after separation from the group. The percentage of time spent on different behavior at different hours also differ significantly (P < 0.05) after separation from the group as compared to when the ewes were in the group. Therefore, it can be concluded that seclusion from the group elicits a significant stress on animals, which may be due to emotional distress.

Study of circadian rhythmicity of physiological response and skin temperature of sheep during summer and winter in semi-arid tropical environment

The present study aimed to evaluate the circadian rhythmicity of some physiological variables, including rectal temperature (RT), respiration rate (RR), heart rate (HR) and skin temperature (ST) in sheep during the summer and winter in semi-arid tropical environment. Eight Malpura rams of 3-4year of age with an average body weight of 37.1±1.99kg were selected for the study. All the animals were fed individually for a maintenance requirement on a body weight basis. The RT, RR, HR and ST values were measured in each animal at 3hour intervals for 24 consecutive hours. Ambient temperature (DBT) and relative humidity (RH) was also recorded inside the shed at the time of physiological parameter study. The cosinor analysis showed a daily circadian rhythm (P<0.01) in RR, HR and ST values during the summer and winter in sheep under semi-arid environment. The RR, HR and ST differ significantly (P<0.05) between summer and winter. The amplitude of RR, RT and ST differ significantly (P<0.05) between the seasons. The results indicate that the circadian rhythmicity of RR, HR, RT and ST during summer and winter changed as expected in compliance to the seasonal requirements of animals adaptability.

Climate Changes, Water Use and Survival During Severe Water Deprivation

The global total water resources available for consumption are only 0.7%. In addition to that, climate change is worsening the situation. In such condition the water availability for livestock is reducing. Water is an essential component for several vital functions of the body such as regulation of body temperature, growth, reproduction, reaction and digestion. Drinking water scarcity is common during summer in tropical environment. Although the native sheep breeds of arid and semi-arid regions are well adapted to the water shortage as well as heat stress, still the insufficiency of water in summer months affect their physiology and compromise their productive performance. The adapted native sheep of arid and semi-arid region endeavour with some anatomical, physiological and behavioural modifications to reduce the demand of water in the body. Livestock loses body water through urine, faeces, respiratory evaporation and sweating. Most of the mammals die when more than 15% water is lost from their body. The water requirements for sheep are met through drinking water, feed water and metabolic water. The water intake of sheep depends on the available feed stuff, environmental temperature, individual animal and its physiological stages, and water quality. The decreased water intake in sheep reduces body weight and feed intake, and increase blood osmolality due to haemoconcentration. The endocrine levels especially stress hormone and metabolic hormone levels are also altered with water insufficiency in sheep. The reduced water availability also affects the reproductive events of the animal and ultimately their production performance is compromised.

Effect of thermal exposure on physiological adaptability and seminal attributes of rams under semi-arid environment

Thermal stress in hot semi-arid environment is a major limitation of sheep production in tropical and sub-tropical climatic condition. The animals tend to maintain homeostasis through physiological adjustments in a hot environment (maximum temperature reaches up to 47.5°C). Therefore, the present study was carried out to assess the effect of thermal exposure on physiological adaptability and seminal attributes of rams under semi-arid environment. The experiment was conducted for eight weeks involving sixteen Malpura crossbred rams (GMM: Garole X Malpura X Malpura). The rams were divided equally into two groups, designated as G1 and G2, respectively. The rams in G1 (Control) group were kept in a sheep shed under naturally prevailing environment without artificial manipulation of ambient temperature (Temperature 30.48±0.38°C; Relative Humidity 28.59±1.15%). The rams of G2 group were exposed to different temperature at different hours of the day (38°C at 1000-1100h; 40°C at 1100-1200h; 42°C at 12:00-1300h; 43°C at 1300-1400h; 44°C at 1400-1500h and 42°C at 1500-1600h) in a climatic chamber for thermal exposure. Physiological responses, blood biochemical profile, blood endocrine profile, sexual behavior and seminal attributes were measured for both the groups. Thermal exposure significantly (P<0.05) increased the water intake; respiration rate, rectal temperature and skin temperature at afternoon in rams. Exposure of rams to thermal stress (G2) significantly (P<0.05) increased cortisol level and decreased tri-ido-thyronine level. The latency period after the first ejaculation, decreased significantly (P<0.05) in G2. The percentage of rapid motile sperm, linearity and average path velocity of sperm were also altered significantly (P<0.05) in thermal exposed rams as compared to control. However, comparable feed intake, body weight, and major blood biochemical parameters, as well as acceptable semen quality attributes of all the rams indicated that the Fec B gene introgressed Malpura cross rams adapted to the thermal exposure under semi-arid tropical climate.

Comparative physiological responses of stress in sheep selected for resistance or susceptibility to Haemonchus contortus in semi-arid tropical region during different seasons

Abstract The present study was conducted to assess the comparative physiological responses of stress in sheep selected for resistance or susceptibility to Haemonchus contortus in the semi-arid region during different seasons. A total of 20 adult Malpura sheep from resistant and susceptibility line were selected for study. The intensity of strongyle infection, blood biochemical and cortisol levels were estimated monthly basis while meteorological data were collected everyday throughout the year. The temperature-humidity index was the highest during dry-hot season. The faecal egg count increased significantly (p < 0.05) during June–August (rainfall season) in susceptible sheep as compared to resistant sheep. The plasma cortisol level increased significantly (p < 0.05) in both the groups during dry hot (March–May) season and it remained higher in the susceptible line till June–August. The total plasma protein reduced significantly during hot-humid with scantly rainfall (September–November) season as compared to other season in susceptible line. It is pertinent to conclude that though sheep remained in stress during dry hot (March–May) season, but effects of stress on the intensity of strongyle infection and blood biochemical were better tolerated by animals of resistant line during hot-humid season compared to susceptible line under semi-arid region.

Effect of altered ambient temperature through shelter modifications on physiological indicators of Malpura lambs reared in semi-arid region during winter

Microclimatic factors are of crucial aspect for the welfare of animals. Therefore, a study was conducted to assess the effect of altered ambient temperature through shelter modifications on physiological indicators of Malpura lambs reared in the semi-arid region during winter. Twenty-one Malpura lambs of 3-5 week age and average body weight 9.97 ± 0.51 kg were used in the present study. The lambs were divided into three groups (eg. G1, G2, and G3) and were kept in the different microenvironment by manipulation of shelter design. The G1 lambs were maintained at lower minimum temperature (8.59 ± 0.71 °C) in asbestos roofed shed, while G2 lambs were maintained at higher minimum temperature (14.59 ± 0.54 °C) in local handmade bamboo dome structure, and G3 lambs were kept at a medium minimum temperature (11.84 ± 0.64 °C) in thermocol insulated roofed shed from evening 18:30 h to morning 07:00 h. The study was carried out for one month between January and February. The parameters studied were physiological response (respiration rate, pulse rate, rectal temperature), skin temperature, blood metabolites and endocrine profile. The data were analyzed by general linear models. Higher average daily weight gain was recorded in the lambs kept in higher minimum temperature groups (20.54% higher in G2 and 24.68% higher in G3) as compared to G1 lambs. Microenvironment manipulation had no significant (P > 0.05) effect on most of the physiological response and skin temperature except morning respiration rate within low-temperature range. The present study reveals that Hb, PCV, T3, and cortisol level were significantly (P < 0.05) influenced by microenvironment manipulation. The results of the study indicated that altered ambient temperature through altered shelter design of housing for raising of lambs in the semi-arid tropical region may support animal welfare during chilling nights of the winter.

Biological rhythmicity of the plasma antioxidant defence in lambs following supplementation of micronutrients or providing shelter in temperature-controlled microenvironment in summer

Abstract Antioxidant defence is one of the important biological adaptations to thermal stress in animals. Micronutrients play crucial roles in the bioactivity of several antioxidant systems. Shelter management by providing a thermo-comfort micro-environment to animals may also combat the heat stress during summer. Hence, the aim of the present study was to assess the biological ability of Malpura lambs to counter thermal stress following supplementation of micronutrients and providing shelter in a temperature-controlled climatic chamber during the hot day-hours in summer. Twenty-one lambs of 3 - 5 months age were equally divided in to three group viz. Group1: control, Group2: micronutrient- supplemented and Group3: housing in thermo-neutral climatic chamber. Lambs in group1 and 2 were maintained in a shed having free access to hot wind while the lambs in group 3 were kept inside a climatic chamber (temperature and relative humidity about 30 °C and 40%, respectively) between 10 am to 4:30 pm. All the lambs were provided identical diet consisting of 2.5 kg concentrate and ad libitum quantities of Cenchrus ciliaris hay and clean water. Group3 lambs were additionally supplemented with 0.150 g micronutrient pellet per animal per day for a period of 30 days. Blood samples were collected at 0, 15, 30 days and plasma antioxidants activity were estimated. The catalase activity in the micronutrient-pellet supplemented group was significantly (p < 0.05) higher than the control both at day15 and day30. The superoxide dismutase activity was increased significantly (p < 0.05) at day30 than the day0 in both the micronutrient-supplemented and climatic chamber groups. In conclusion, both the micronutrient supplementation and housing in a thermo-comfort environment enhance the antioxidant defence and biological adaptation in lambs during thermal stress in summer.

Seasonal rhythmicity of thermoregulatory physiological responses in fat-rumped sheep under semi-arid tropical environment

ABSTRACT The immediate response of animals to fluctuations in environmental temperature is an alteration in their physiological responses. For those who failed to cope, their production performance is affected greatly. Fat-rumped sheep is phenotypically different from the commonly available sheep breeds of the semi-arid tropical environment in India. For assessment of thermoregulatory rhythmicity under extreme seasonal variations of the semi-arid tropical region, six adult fat-rumped (Dumba) rams were selected. The study was carried out in the year 2016–2017. All the rams were maintained under stall-feeding condition with a fixed dietary regime. Respiration rate (RR), pulse rate (PR), skin temperature (ST) and rectal temperature (RT) were recorded at morning (08:00 h), and afternoon (14:00 h) in summer (May–June), winter (December–January) and spring (March–April) for six times in each season at 7 days interval. Body weight was taken at the start and end of each season under study. The meteorological data were recorded twice daily at 8:00 h and 14:00 h for the entire study period. The study indicated significant (p < 0.05) variation in RR, PR and ST with respect to season. RT and body weight showed no significant variation among seasons. The result indicated fat-rumped sheep altered their thermoregulatory physiological responses as per the change of season to cope with environmental extremes under semi-arid tropical region.

Impact of Climate Change on Sheep Reproduction

The climate is changing faster than the predictions, with expectations of more frequent warm spells, heat waves and heavy rainfall in the future. The magnitude of these will depend on the geographical features of that region. The extreme environmental conditions due to change in climate will impose various stresses on sheep and consequently will adversely affect their reproductive performance. Animals will experience heat stress due to high temperature and more solar radiation, and nutritional stress due to reduced quantity and quality of feed because of low rainfall, more droughts, poor crop yields and less pasture growth. Reproduction is a complex process that involves a timed sequence of physiological and psychological events governed by hormones, metabolites and environmental signals. In both the sexes, these events are very sensitive to high temperature and under-nutrition. Nearly all the reproductive processes such as gametogenesis, puberty, gamete transport, fertilization, early embryonic development, maternal recognition of pregnancy, gestation, parturition and post-partum recovery are influenced by environmental stresses either directly by affecting the functions of reproductive organs or by blocking the hormone-mediated cellular functions of the hypothalamic-pituitary-gonadal (HPG) axis. Sheep husbandry is the main activity of livelihood security of large populations in hot arid and semi-arid climates and is based on grazing. Sheep often have to walk long distances under hot solar radiation and they experience deprivation of feed for short or long periods. The potential effects of climate change on sheep reproduction would be increased incidence of reproductive disorders such as delayed puberty, fertilization failure, embryo mortality, retardation of foetal development and growth, abortion, and premature or still birth, culminating in low reproductive efficiency of animals. Further, climate change may affect seasonal breeding in sheep due to mismatch of nutrient availability with commencement of reproductive activities.

Mitigation of Climatic Change Effect on Sheep Farming Under Arid Environment

Livestock is the integral part of agricultural systems all over the world. However, in India, climate change has become a serious concern for ensuring nutritional security for the growing population. Small ruminants, especially pastoral farming, serve a major livelihood option and are embedded deep in the culture of resource-poor small and marginal farmers of arid and semiarid western India. The breeds of these arid and semiarid region are well adapted to the local climatic condition and have amalgamated themselves to very harsh climatic factors in the region. The local native animals of this region have their own adaptive mechanism of altering physiological, neuroendocrine, biochemical, cellular, and molecular process to encounter the stress; still, they need to endure stressful conditions due to high temperature, low feed, and water scarcity. All these constraints expose the sheep production into heat stress, nutritional stress, water stress, walking stress, and their combinations. All the stress factors affecting sheep production directly and indirectly and ultimately lead to compromised performance, lower efficiency, and increased mortality and affect the immune system. Giving the poor farmer’s economic security, under changing climatic scenario, sheep production has to be sustainable by combating the detrimental effect of different mitigation strategies. In the present chapter, the mitigation strategies have been discussed which include genetic improvement, breeding management, grazing management, nutritional management, utilization of unconventional feed resources, antioxidant supplementation, water management, shelter management, and disease management. Basically, all these strategies are based on a physical modification of the environment, genetic modification, and improved nutritional management. To get optimum production under changing climatic scenario, holistic approach is needed as per the environmental conditions and available resources.