پردیس کشاورزی و منابع طبیعی دانشگاه تهران Iranian Journal of animal Science 2008-4773 48 4 2018 02 20 Effect of dietary betaine supplementation and vitamin B12 injection during the transition period on fatty acids profile of milk in Holstein dairy cows Effect of dietary betaine supplementation and vitamin B12 injection during the transition period on fatty acids profile of milk in Holstein dairy cows 493 503 65465 10.22059/ijas.2017.243378.653567 FA Ali Gohardust M.Sc. Student, Department of Animal Sciences, Faculty of Agriculture, Lorestan University, Iran Arash Azarfar Associate Professor, Department of Animal Sciences, Faculty of Agriculture, Lorestan University, Iran 0000-0002-7594-3623 Ali Kiani Associate Professor, Department of Animal Sciences, Faculty of Agriculture, Lorestan University, Iran Amir Fadayifar Assistant Professor, Department of Animal Sciences, Faculty of Agriculture, Lorestan University, Iran 0000-0003-2957-7623 Journal Article 2017 10 23 In this research effects of dietary supplemention with betaine and injection of vitamin B12 during the transition period on profile of milk fatty acids was investigated using 32 Holstein dairy cows. Experimental treatments included control (a basal diet without any supplementation; CC), CB (supplemnting with 50 g of rumen unprotected betaine per day per head during the transition period), BC (injection of 0.5 mg vitamin B12 in a 10-days interval) and CC (supplemnting with 50 g of unprotected betaine per day per head plus injection of 0.5 mg vitamin B12 in a 10-days interval. The CB and BB significantly increased denovo synthesis of fatty acids in mammary gland and milk fat concentration of saturated fatty acids (P<0.05). Experimental treatments had no effect on milk fat concentratios of total mono-unsaturated fatty acids, C14: 1, C16: 1, C18: 1n9t, C18:1n9c and C20:1 (P> 0.05). Milk fat concentration of polyunsaturated fatty acids was higher in cows recived CB than in BC and BB cows, but similar to CC cows. Experimental treatments had no effect on perentage of milk fat and plasma concentration of glucose (P>0.05). In conclusion, to inceraese denovo synthesis of fatty acids in mammary glands intarmuscualr injection of vitamin B12 in transition cows is recommended.  In this research effects of dietary supplemention with betaine and injection of vitamin B12 during the transition period on profile of milk fatty acids was investigated using 32 Holstein dairy cows. Experimental treatments included control (a basal diet without any supplementation; CC), CB (supplemnting with 50 g of rumen unprotected betaine per day per head during the transition period), BC (injection of 0.5 mg vitamin B12 in a 10-days interval) and CC (supplemnting with 50 g of unprotected betaine per day per head plus injection of 0.5 mg vitamin B12 in a 10-days interval. The CB and BB significantly increased denovo synthesis of fatty acids in mammary gland and milk fat concentration of saturated fatty acids (P<0.05). Experimental treatments had no effect on milk fat concentratios of total mono-unsaturated fatty acids, C14: 1, C16: 1, C18: 1n9t, C18:1n9c and C20:1 (P> 0.05). Milk fat concentration of polyunsaturated fatty acids was higher in cows recived CB than in BC and BB cows, but similar to CC cows. Experimental treatments had no effect on perentage of milk fat and plasma concentration of glucose (P>0.05). In conclusion, to inceraese denovo synthesis of fatty acids in mammary glands intarmuscualr injection of vitamin B12 in transition cows is recommended.  https://ijas.ut.ac.ir/article_65465_01c37af10a2ad06930dc84bb2646bda8.pdf