Roychoudhury, R.PATHAK, PRASANTA KUMAR2018-10-052018-10-052016-07http://krishikosh.egranth.ac.in/handle/1/5810074836Eighteen weaned piglets (at 56 days) from each of the two different genetic groups viz. Hampshire and Hampshire x Local irrespective of sex were selected and randomly divided into three dietary groups viz. Gr.I, Gr.II and Gr.III consisting of 6 animals of almost similar body weight in each experimental group for winter months in 1st phase and summer months in 2nd phase to find out the status of important season related thermal stress biomarkers as well as most suitable germplasm in terms of growth performance under the agro-climatic condition of Assam. The experiment was also aimed to study the role of different level of energy ration in the growth performance of pigs in different seasons. A total of 3 rations were prepared for grower and finisher stage as per the NRC feeding standard for pig (NRC, 1998). The ration having 110, 100 and 90 per cent energy of NRC (1998) designated as high energy (HE), medium energy (ME) and low energy (LE), respectively. The ME, LE and HE treatment were represented three dietary groups of pigs i.e. Gr.I, Gr.II and Gr.III, respectively for both winter and summer. The Gr.I (ME) was considered as control group for both winter and summer season. Temperature-Humidity Index (THI) was calculated out from the data of ambient temperature and relative humidity (RH). The physiological parameters such as respiration rate (RR) and rectal temperature (RT) were recorded following conventional methods in two phases in a month i.e., consecutively for three days in a week in each animal and twice daily at 8:30 A.M. and 5:30 P.M. for a period of 12 months. About 5 ml of blood was collected from each experimental animal aseptically at 15 days interval for the whole experimental period. The level of thermal stress related blood hormones such as triiodothyronine (T3), thyroxine (T4) and cortisol were estimated by Radioimmunoassay (RIA) technique. The animals were weighed in the morning before feeding and watering at fortnightly intervals. The linear body measurements of the animals were recorded at monthly intervals. The feed intake, feed conversion efficiency and economics of feeding were also recorded. The ambient temperature was significantly (P<0.01) higher in the evening (23.60-29.51 0C) than in the morning (20.02-28.03 0C). The present experiment indicated that average ambient temperature during summer months (27.33-29.51 0C) were above the comfort zone for pigs (22 0C). The significantly (P<0.01) higher RH (%) was recorded in outdoor environment (87.26-91.10%) and in the morning time (86.60-91.10%). The THI during the study period was found to be indicative of thermal stress to the experimental animals during summer (79.55 – 82.56) as compared to the winter seasons. Physiological parameters viz., RR and RT were significantly (P<0.01) higher in summer season (43.75-72.12 breaths/min. and 102.29-103.23 0F/min.) than the winter season and non-significantly higher values were recorded in Hampshire as compared to Hampshire x Local during summer season. It was also found that the significantly (P<0.01) lower RR as well as RT was recorded in the pigs fed with high energy (HE) ration during summer season. Serum T3 and T4 concentrations were significantly (P<0.01) lower during summer as compared to winter in both Hampshire and Hampshire x Local pigs, while both the genetic groups showed significantly (P<0.01) higher concentration of serum cortisol during summer season. It was also observed that thyroid hormone and cortisol concentrations were maintained in groups of pig fed HE diet during summer. The average body weight was significantly (P<0.01) higher in winter and Hampshire pigs attained higher body wt. but observed that Hampshire pigs shed more body wt. in summer as compared to crossbred. It was also recorded that energy level of diet had significant (P<0.01) influence on the body weight gain and minimizes the production losses in terms of body wt. gain during summer. The coefficient of correlation of linear body measurements with the body weight of experimental pigs was found to be positively correlated and found that linear body measurements were in progressively increasing trend along with increase in body weight. The study also revealed higher FCE during winter season and Hampshire x Local pigs had higher FCE. The lower feed intake and higher FCE was recorded in HE incorporated group. The present study revealed that the cost of concentrate feed decreased along with reduction in the energy level of the diet. The cost of feeding per kg body weight gain was higher in summer than winter season and lower cost of feeding per kg gain was recorded in HE incorporated group. On the basis of this finding it can be concluded that winter is the best time for raising growing-finishing pigs. During summer most of the time the state remains under tropical high heat and humid dominance which may drastically affect the production and eventually economy of pig farming. From the present observation, it is suggested that Hampshire x local pigs may rear economically in the agro-climatic condition of Assam and increasing the energy density of diet can also help to minimize the effects of thermal stress during summer.ennullThesis