Acta Veterinaria et Zootechnica Sinica ›› 2020, Vol. 51 ›› Issue (8): 1895-1902.doi: 10.11843/j.issn.0366-6964.2020.08.013

• ANIMAL NUTRITION AND FEEDS • Previous Articles     Next Articles

Effect of Dietary Cobalt Levels on Lactation Performance, Nutrient Digestibility and Plasma Biochemical Parameters in Lactating Dairy Cows

LIN Miao, SUI Yannan, AN Yujie, ZONG Yujie, FENG Limei, WANG Kuopeng, HU Zixuan, ZHAO Guoqi*   

  1. College of Animal Science and Technology, Yangzhou University, Yangzhou 225009, China
  • Received:2020-01-19 Online:2020-08-25 Published:2020-08-19

Abstract: The aim of this study was to determine the effects of different dietary cobalt (Co) supplemental levels on lactation performance, nutrient digestibility and plasma biochemical parameters in lactating dairy cows. Thirty mid-lactation Holstein dairy cows were blocked and randomly divided into 5 groups which were fed with basal diet (control group) and experimental diets (4 experimental groups), and the experimental diets were supplemented with Co of 0.15, 0.30, 0.75 and 1.50 mg·kg-1 DM as CoCO3, respectively. The experiment was conducted for 56 d, including 14 d of adaptation and 42 d of trial period. Dairy feed intake and milk yield were recorded every day, milk samples were obtained for component determination, feed and fecal samples were collected for apparent nutrient digestibility determination, blood samples were taken for biochemical parameters determination. The results showed that there was no significant effect on dry matter daily intake (DMI) or milk contents at all Co supplemental levels compared with control group (P>0.05). However, the milk yield was increased by adding cobalt of 0.30 and 0.75 mg·kg-1 DM (P<0.05). Acid detergent fiber (ADF) and crude protein (CP) digestibility increased significantly at 0.75 mg·kg-1 DM group compared with control group (P<0.05). Co supplemental level of 1.50 mg·kg-1 DM resulted in the decrease of plasma glucose and aspartate aminotransferase (AST) activity (P<0.05), while 0.75 mg·kg-1 DM group decreased the activity of alanine aminotransferase (ALT) and alkaline phosphatase (ALP) (P<0.05). Red blood cells (RBC), hemoglobin (HGB) concentration and hematocrit (HCT) were quadratically increased (P<0.05). The recommended level of dietary Co for mid-lactation Holstein dairy cows is between 0.30 to 0.75 mg·kg-1 DM, the optimal level is 0.73 mg·kg-1 DM in this study.

Key words: cobalt, Holstein dairy cows, lactation performance, nutrient digestibility, plasma

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