RELATIONSHIPS OF TEAT CONFORMATION AND UDDER HEIGHT TO MILK FLOW RATE AND MILK PRODUCTION IN HOLSTEINS

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Teat conformation characteristics, udder height, total milking yield, 2-min yield, 2-min yield adjusted for the linear and quadratic effects of total milking yield, and 305-day milk and fat yields were recorded on 377 Holstein-Friesian cows in 18 herds. Simple relationships of teat conformation measures and udder height to milk flow rate and production traits which were significant (P < 0.05) were as follows. Mean 2-min, total milking, and 305-day milk yields were lower for plumb front teats than for front teats that were not plumb. Cows with plumb rear teats also had lower total milking yields. Cows with cylindrical teats, both front and rear, had lower total milking yields than cows with funnel teats. Teat length was positively correlated with total milking, 305-day milk and 305-day fat yields. Teat diameter measures taken at proximal, medial and distal locations of the teat were positively correlated with all production traits, and rear teat diameter measures were positively correlated with 2-min yield. Udder height was positively correlated with adjusted 2-min yield and negatively correlated with total milking, 305-day milk and 305-day fat yields. Least squares analyses, which corrected for the effects of herd, age of cow at calving, and stage of lactation, were conducted, and significant (P < 0.05) effects were as follows. Cows with cylindrical teats produced 0.7–0.8 kg less total milk at milking than cows with funnel teats. Rear teat diameter was more highly related to milk production than front teat diameter. Proximal and distal diameter of the rear teat was positively associated with all three production traits, and medial rear teat diameter was positively associated with total milking and 305-day milk yields. Also, proximal diameter of the rear teat had a positive relationship with 2-min yield. Total milking yield was positively influenced by front teat proximal and medial diameters, but medial diameter had a negative effect on adjusted 2-min yield. Udder height influenced all traits. High udders had relatively higher milk flow rates but lower milk and fat production. Each centimetre increase in udder height was associated with a 46-kg decrease in 305-day milk. Heritabilities of 2-min yield, adjusted 2-min yield, 305-day milk yield and 305-day fat yield were 0.17, 0.27, 0.18, and 0.50, respectively.