Variations in Type Ratings of Individual Ayrshire Cows

Abstract

Eighty Ayrshire cows at the W. Virginia Agric. Expt. Station were rated for type an average of 5 times over a period of A1/2 yrs. by 9 inspectors. There were 5 grades used: Excellent, Very Good, Good Plus, Good and Fair. A summary shows that 54 animals, or 67.5%, changed only one grade or less during the 41/2-yr. period, while 26, or 32.5%, had a range of 2-3 grades. A study of the reasons for changes in ratings showed that the repeatabilities between ratings given a cow by the same inspector at different times ranged from 0.62 to 0.82, while the correlation between ratings given the same cow by different inspectors at different times was calculated to be 0.55. Thus a change in inspectors influenced the rating. A study of 65 animals classified several times as 3-, 4- and 5-yr.-olds indicated that the change in type rating due to advancement in age is not great but is statistically significant between the ages of 4 and 5 yrs. Stage of lactation also affected the type rating of cows. There was a statistically significant higher rating obtained when animals were classified shortly before or after freshening in contrast to the ratings made in the middle segment of the lactation period. It was concluded that several type ratings on an individual cow form a far more accurate guide to her true type conformation than does one single rating.