Variation in Type Appraisal Scores Due to Sire and Herd Effects

Type classification records of 15,697 Brown Swiss cows by 1955 sires in 852 herds were analyzed with a crossclassified (herd-year and sire of cow) model. Fractions of variance due to herd-year effects ranged from 8% for mammary system to 17% for body capacity. Within herd-year heritabilities ranged from 24% for feet and legs to 43% for final score. Descriptive traits were analyzed by the same model except that each category was treated as a binomial variable. Proportions of variance due to herd-year effects for the descriptive traits were generally below 10%. Heritabilities were generally below 15%.

“…For descriptive traits, variance components due to herd-years were generally even smaller than for the standard type traits. These .~ results agree with (2,13,17,25).…”

Section: ~0~0supporting

confidence: 82%

Genetic and Herd-Year Variation in Type Traits of Brown Swiss Cows

Mínguez

Wiggans

Vleck

1979

“…Age effects within lactation groups, with stage of lactation and year-season effects eliminated, were negligible in first and second lactation groups but were of some importance in the later lactation group (Table 2). Increases in udder infection with age have been found previously for leukocyte score (14) and California mastitis test scores (3), for bacterial infection (]], 14), and for clinical mastitis (11,12).…”

Section: Resultsmentioning

confidence: 86%

“…The possibility of selection to reduce infection rates has been raised by indications of genetic resistance to udder infections (1,6,8,12). Other work, however, has found either no genetic resistance (10) or varying estimates depending on the criterion of infection (11).…”

Section: Introductionmentioning

confidence: 99%

Genetic and Environmental Aspects of Udder Infections

Wilton¹,

Vleck²,

Everett³

et al. 1972

Information on the presence or absence of bacterial infections and abnormal secretions in each quarter of cows in their initial survey on the New York State Veterinary College Mastitis Program was used to obtain several criteria of udder infection. Year-season and stage of lactation effects were statistically significant for several criteria of infection in first, second, and later lactation groups but did not explain much of the variation in any infection criterion. Age within first and second lactation group also accounted for little of the variation in infection although age within later lactations accounted for up to 5% of the variation in some criteria.Heritabilities from sire components of variance were all low for first, second, and later lactation cows. Heritabilities from daughter-dam regression were low for first and second lactation cows but moderately high for later lactation cows. Regression of second lactation infections on first lactation infections, later lactation infections on first lactation infections, and later lactation infections on second lactation infections were moderately high. tteritabitities from sire components of variance were not increased by using two surveys per cow, by using only herds with high incidence of infections, or by using only sires with large nmnbers of daughters. Phenotypic relationships between milk yield and infections were all low. Some of the overall measurements of infection on later lactation cows had genetic correlations of" approxinmtely .3 with first lactation milk production.

“…Estimates were from .24 to .40 for temperament, depth of barrel, strength of rear attachment, udder texture, and milking quality. Van Vleck (27) obtained paternal half-sib heritabflities from data of 1,400 Holsteins under 35 months of age and 4,080 older cows. Heritabilities for resistance to mastitis and ketosis, milking speed, dairy character, shoulder tightness, depth of body, upstandingness, levelness of udder floor, depth of udder, strength of rear and fore udder attachment were all near .25.…”

Section: Introductionmentioning

confidence: 99%

“…Herd or year effects on type ratings have generally been smaller than on milk production (3,13,16,23,27,30). Van Vleck (27) and Carter, Rennie, and Burnside (3) suggested herdmates need not be considered when reporting type ratings for sires' daughters.…”

Section: Introductionmentioning

confidence: 99%

Type Appraisal: II. Variation in Type Traits Due to Sires, Herds, and Years

Norman

Vleck

1972

Variance components were estimated from type appraisal data to determine the importance of year, herd, sire, and herd x sire effects uport 49 body, udder, and management traits. Estimates were based on over 16,000 appraisals on daughters of Holstein artil~cial insemination sires. The variation explained by these effects never exceeded 34g of the total variance. Year effects were almost nonexistent (--2 to 3g). Herd effects were small for all traits except feeding speed, body weight, intensity and persistency of edema, and ketosis, and never exceeded 25g.Most appraisal traits had low heritabilities. The estimate for milking speed was .23 while estimates for other management traits were less than .08. The estimates for body weight and upstandingness were .40 and .39. Other body traits having estimates from .16 to .21 were sharpness, height of thurls, depth of body, levelness of rump, tightness of shoulders, and height of tail setting. The heritability estimates for udder traits were low. Estimates for only three of 21 udder traits exceeded .14. These were strength of rear attachment, rear teat spacing, and depth of udder.