Effect of somatic cell count on milk fat and protein in different parities and stages of lactation in Holstein cows

Acta Agriculturae Slovenica

Abdol Ahad SHADPARVAR¹  Arash CHEGINI¹  Navid GHAVI HOSSEIN-ZADEH¹  Hossein HOSSEINI-MOGHADAM¹ 

[1] University of Guilan, Faculty of Agricultural Sciences, Department of Animal Science, Rasht

关键词: cattle;    dairy cows;    breeds;    Holstein;    milk;    proteins;    fat;    somatic cell score;    lactation;    Iran;   

DOI  :  10.14720/aas.2017.110.1.5

学科分类：农业科学（综合）

来源: Univerza v Ljubljani * Biotehniska Fakulteta / University of Ljubljana * Biotechnical Faculty

【 摘 要 】

The objective of this study was to investigate the effect of somatic cell score (SCS) on milk fat and protein in different parities and stages of lactation in Iranian Holstein cows. Records between June 2003 and January 2014 from 208,478 cows in lactations one to nine in 845 herds, comprising 2,456,303 monthly test-day (TD) records were used. The MIXED procedure of the SAS software with repeated measurements was used. The fixed effects of the model were herd, year-season of calving, month of TD, weeks of lactation, previous dry period length and somatic cell score (SCS) and covariate was calving age. Lactations were divided into six stages and analyses were performed within each stage. Also, different lactations were analyzed separately. Increase of SCS led to increase of milk fat and protein percentage and the increase of milk fat and protein associated with SCS was higher in early stages of lactation relative to later stages of lactation. Also, increase of milk fat and protein associated with SCS was higher in the first lactation rather than later lactations and decreased with increase of parity.

【 授权许可】

CC BY-NC-ND