Evolving Appropriate Time Of Feeding Without Altering The Feed Ingredients / Forage For Enhancing Rumen Microbial Biomass In Cattle

TITLE : EVOLVING APPROPRIATE TIME OF FEEDING WITHOUT ALTERING THE FEED INGREDIENTS / FORAGE FOR ENHANCING RUMEN MICROBIAL BIOMASS IN CATTLE NAME : C. BANDESWARAN DEGREE TO WHICH SUBMITTED : Ph.D. (Animal Nutrition) CHAIRMAN : Dr. R. Karunakaran, Ph.D. DEPARTMENT : Animal Nutrition COLLEGE : Madras Veterinary College YEAR : 2010 UNIVERSITY : Tamil Nadu Veterinary and Animal Sciences University, Chennai – 51 A study was under taken to bring out a possible ruminal delivery of synchronized energy and protein to enhance ruminal microbial biomass in cattle by evolving appropriate time of feeding without altering the feed ingredients in four roughages (Napierbajra hybrid grass, sugarcane tops, sorghum stover and paddy straw) based feeding systems located in five agro-climatic zones of Tamilnadu. A survey with 120 farmers having low milk yielding dairy cattle in four roughage based feeding systems revealed that 53.3, 50.0, 53.3 and 36.7 per cent of farmers feed twice daily during morning and evening with Napier-bajra grass, sugarcane tops, sorghum stover and paddy straw respectively. Groundnut oil cake along with de-oiled rice bran were fed by 33.3, 20.0 23.3 per cent of farmers in the forenoon and evening in NB hybrid grass, sugarcane tops and paddy straw based feeding systems respectively. Only 26.7 per cent of farmers feed coconut oil cake along with de-oiled rice bran twice daily during forenoon and evening in sorghum stover based feeding system. In Napier-bajra hybrid grass based feeding system, the NB hybrid grass, groundnut oil cake, de-oiled rice bran were fed at 65.8, 8.8 and 25.4 per cent, respectively. In sugarcane tops based feeding system, the sugarcane tops, paddy straw, groundnut oil cake, de-oiled rice bran were fed in the proportion of 51.9, 25.2, 8.1 and 14.8 per cent, respectively. The sorghum stover, coconut oil cake and de-oiled rice bran were fed in the proportion of 71.8, 12.1 and 16.1 per cent respectively in sorghum stover based feeding system. The paddy straw, groundnut oil cake and de-oiled rice bran were fed in the proportion of 75.8, 8.0 and 16.2 per cent, respectively in paddy straw based feeding system. The respective half time (t1/2) of organic matter and nitrogen determined by in vitro (TANUVAS RUSITEC) for NB hybrid grass, sugarcane tops, sorghum stover and paddy straw were 16  1 and 14  2, 27  2 and 24  1, 27  4 and 34  4 and 29  2 and 40  6 h, respectively. The respective t1/2 time of organic matter and nitrogen for the commonly fed supplemental feeds viz., groundnut oil cake, sesame oil cake, coconut oil cake and de-oiled rice bran were 7  1 and 9  1, 5  1 and 8  1, 7  1 and 15  2 and 8  0 and 7  1 h, respectively. Based on t1/2 of organic matter from roughage and de-oiled rice bran and t1/2 of nitrogen from oil cake, the existing farmer feeding strategy (FFS) was modified without altering the type and quantity of forage / feed ingredients in evolved feeding strategy (EFS). The influence of feeding strategies was tested by simulated feeding in semi continuous culture system (RUSITEC) for their efficiency of synthesizing rumen microbial protein. The results indicated that at 48 h of incubation, the dry matter and organic matter degradability was significantly (p<0.055) higher in NB hybrid grass, sugarcane tops and sorghum stover based evolved feeding strategies compared to respective farmers feeding strategies except in paddy straw based feeding strategy. The rumen microbial protein production per day was significantly higher in NB hybrid grass (p=0.056) and sorghum stover (p=0.014) based evolved feeding strategies. Validation of the in vitro finding by comparing evolved feeding strategy with farmer’s feeding strategy on rumen microbial nitrogen synthesis estimated from purine derivatives (PD) excretion in crossbred cattle, male calves revealed that the microbial nitrogen synthesis per kg metabolic body weight of animal was comparable between evolved feeding strategy and farmer’s feeding strategy irrespective of type of feeding system. However, a non significant increase of 5.02 and 1.0 per cent microbial nitrogen production per kg metabolic body weight of animal in evolved feeding strategies were observed in NB hybrid grass and sorghum stover based feeding systems, respectively. It may be concluded that evolved feeding strategy of Napier-bajra hybrid grass, sugarcane tops, sorghum stover and paddy straw based feeding systems did not significantly enhanced the rumen microbial nitrogen synthesis and growth rate of calves. Hence, it is recommended to adopt farmer’s feeding strategies in all the four roughages based feeding systems.