SOURCES OF VARIATION IN YIELDS AND CONCENTRATIONS OF MILK SOLIDS IN DAIRY-COWS

被引:14
作者
ROOK, AJ [1 ]
FISHER, WJ [1 ]
SUTTON, JD [1 ]
机构
[1] AFRC,INST GRASSLAND & ENVIRONM RES,BERNARD WEITZ CTR,READING RG2 9AQ,ENGLAND
来源
ANIMAL PRODUCTION | 1992年 / 54卷
关键词
DAIRY COWS; DIURNAL VARIATION; MILK COMPOSITION;
D O I
10.1017/S000335610003676X
中图分类号
S8 [畜牧、 动物医学、狩猎、蚕、蜂];
学科分类号
0905 ;
摘要
Eighteen multiparous Holstein-Friesian cows were offered grass silage ad libitum and 3, 6 or 9 kg dry matter per day of concentrates. Triplicate milk samples were taken at each of two daily milkings over a 28-day period and analysed for fat protein and lactose concentration. Milk yield and fat concentration were more variable than protein and lactose concentrations both between animals and between days. Sampling variation was small for all component concentrations. The main source of variation for all traits was time of milking (morning or afternoon) followed by variation between cows and by day-to-day variation. There was little linear trend with time in the data due to cows being close to peak yield. There was no evidence of cyclical variation over time for any trait. Mean weekly or monthly yields and concentrations were better predicted using samples from four rather than from two consecutive milkings but there was no further advantage from using six samples.
引用
收藏
页码:169 / 173
页数:5
相关论文
共 13 条
[1]   DAY-TO-DAY VARIATIONS IN FAT PERCENT OF COWS MILK [J].
ATWAL, AS ;
ERFLE, JD .
CANADIAN JOURNAL OF ANIMAL SCIENCE, 1990, 70 (02) :731-734
[2]  
Bibby J., 1977, PREDICTION IMPROVED
[3]  
DODD FH, 1977, TECHNICAL B NATIONAL, V1, P179
[4]  
KENDALL MG, 1983, ADV THEORY STATISTIC, V3
[5]   PREDICTING DAILY MILK-YIELD, FAT PERCENT, AND PROTEIN PERCENT FROM MORNING OR AFTERNOON TESTS [J].
LEE, AJ ;
WARDROP, J .
JOURNAL OF DAIRY SCIENCE, 1984, 67 (02) :351-360
[6]  
PEAKER M, 1980, FACTORS AFFECTING YI, P159
[7]  
ROOK AJ, 1992, IN PRESS ANIMAL PROD, V54
[8]  
Siegel S., 1988, NONPARAMETRIC STAT B, Vsecond
[9]  
SPORNDLY E, 1989, SWED J AGR RES, V19, P99
[10]  
Tukey JW, 1977, EPLORATORY DATA ANAL