摘要
Abstract
To understand the seasonal variation in milk yield and milk composition of Holstein cows in Baotou ,6 years'data from 2007 to 2012 of a cattle farm were analyzed to get the variation trend in milk production and milk composition .The results showed that the milk yield in May ,June ,July and August were higher than that of other months ,but protein and fat were lower (months differ at P ≥ 0 .05) .The milk yield in October ,November ,December ,January and February were lower ,but protein and fat were higher(P≥ 0 .05) .In March and September ,milk yield ,protein and fat were at the middle level ( P ≥0 .05) .In March ,milk yield began to rise ,but protein and fat began to fall(the neighboring months from February to May differed at P ≥ 0 .05 ,the interval months differed at P< 0 .05) ,in September ,milk yield began to plummet ,but protein and fat began to soar (August and September differed at P< 0 .05) .There was no significant difference between each month on lactose (P> 0 .05) .The variation of lactose was simi-lar to milk yield ,but contrary to protein and fat .The milk yield in Baotou presented the variation trend of rising in spring ,peaking in summer ,then falling in autumn and bottom in winter ;the variation of protein and fat were opposite to that of milk yield .The milk yield ,protein and fat varied greatly in autumn than in spring .关键词
奶牛/产奶量/乳成分/季节/变化规律Key words
cow/milk production/milk composition/season/variation trend分类
农业科技
