Nutritional evaluation of transgenic cottonseed in the ration of lactating dairy cows Ranjan K. Mohanta & Kamal K. Singhal & Amrish K. Tyagi & Y. S. Rajput & Shiv Prasad Accepted: 13 August 2009 / Published online: 24 August 2009 # Springer Science + Business Media B.V. 2009 Abstract The effects of feeding transgenic (Bt) whole cottonseed (WCS) were studied in lactating cows. Twenty multiparous crossbred cows (Karan Swiss × Karan Fries) in early lactation were given a concentrate mixture containing 40% crushed delinted non-transgenic (non-Bt) WCS, 2 kg wheat straw and green fodder ad lib for a 15-day adaptation period. Thereafter, the cows were divided in two similar groups of 10 each on the basis of milk yield, body weight (BW) and date of calving. The non-Bt control group continued on same ration, while for the Bt group the non-Bt WCS was replaced by transgenic WCS, in a feeding trial of four weeks. The diets provided a minimum of 2 kg cottonseed/cow/d. Mean DMI/100 kg BW and milk yield of non-Bt and Bt groups was 3.48 and 3.45 kg and 11.4 and 12.0 kg/d, respectively. Intake of nutrients, digestibility, milk production and body condition score (BCS) did not differ between the groups (P>0.05), but BW gain was higher (P<0.05) in the Bt group than the non-Bt group, probably as a result of hoof problem in two cows of non-Bt group, which when compared excluding two animals from each group did not differ significantly (P>0.05). Transgenic protein (Cry1C) was not detected in the weekly milk samples or in blood plasma at the end of the experiment, showing that delinted WCS containing Cry1C protein can safely be fed to lactating cows. Keywords Bt protein . Cottonseed . Digestibility . Feed intake . Transgenic Introduction Cottonseed is used as a traditional protein and energy supplement for lactating cows and buffaloes in cotton growing countries. Cotton crop is prone to bollworm pests which cause substantial loss to farmers. So, single or multiple genes from a naturally occurring soil bacterium, Bacillus thuringiensis (cry1C, cry1Ab, cry1Ac, cry1F etc) that produces insecticidal Cry proteins in cotton plant, have been inserted into the cotton plant’ s DNA (Hofte and Whiteley 1989). When ingested, these Cry proteins bind to specific receptors in the midgut of susceptible pests forming ion-selective channels in the membrane killing the Trop Anim Health Prod (2010) 42:431–438 DOI 10.1007/s11250-009-9439-z R. K. Mohanta (*) : K. K. Singhal : A. K. Tyagi Dairy Cattle Nutrition Division, National Dairy Research Institute, Karnal, India e-mail: mohanta.ranjan@gmail.com Y. S. Rajput Animal Biochemistry Division, National Dairy Research Institute, Karnal, India S. Prasad Dairy Cattle Breeding Division, National Dairy Research Institute, Karnal, India