The aims of this study were to estimate the genetic parameters for leg and foot health and mobility in purebred turkey lines and their genetic correlations with BW. Traits were gait score (GS) as an overall measure of leg health, footpad dermatitis (FPD), and 2 skeletal leg health traits, namely, valgus and varus deformities (VVD) and tibial dyschondroplasia (TD). Data from 4 different lines, comprising 3 yr of phenotypic records and 4 yr of pedigree information per line, were used. The sex average BW for the lines at 18 wk ranged from 19.1 kg (line A) to 12.4 kg (line D). The prevalence of VVD ranged from 5.2 to 14.6% and for TD from 4.1 to 23.2%. The average score for FPD on a scale of 0 to 100 ranged from 48.5 to 61.1. Gait Score was scored on a scale of 1 to 5, standardized to a mean of 3 and SD of 1. Heritabilities were estimated at 0.08 to 0.13 for GS, 0.01 to 0.07 for VVD, 0.06 to 0.12 for TD, and 0.10 to 0.15 for FPD (all SE ≤ 0.02). Estimates of the genetic correlations between VVD and TD ranged from 0.03 to 0.21 (all SE ≤ 0.08), and estimates of these with GS ranged from 0.07 to 0.87 (all SE ≤ 0.09). The genetic correlations of FPD with GS ranged from 0.00 to 0.34 (all SE ≤ 0.04), and with the skeletal leg health traits from -0.06 to 0.33 (all SE ≤ 0.06). Body weight showed estimated genetic correlations ranging from 0.28 to 0.51 (all SE ≤ 0.06) with GS, -0.06 to 0.50 (all SE ≤ 0.13) with VVD/TD and 0.05 to 0.34 (all SE ≤ 0.05) with FPD. The results suggest that selection for improved leg health can be incorporated effectively in a commercial turkey breeding program using balanced breeding goals, in which production traits and leg health traits are considered simultaneously.
Progeny of Holstein females mated to sires of different breeds were genetically evaluated along with their purebred Holstein contemporaries born in the same herds using multiple trait animal models. The resulting estimated breeding values (EBV) of cows were averaged within breed of sire and compared relative to progeny of purebred Holstein sires for various economic traits. All progeny were born since 2005, and only animals from herds with crossbreds were included in the genetic evaluation models. Crossbred cows were significantly below Holstein sired cows for 305-d EBV for milk yield, but were above Holsteins for fat and protein yields. There were no significant differences between crossbreds and purebreds for somatic cell scores. Crossbred cows and heifers became pregnant sooner after each calving, had higher non-return rates, fewer services, and shorter gestation lengths than purebred Holsteins. Crossbred heifers and cows had lower stillbirth rates due to having smaller calves, and slightly better calving ease. Objectively measured conformation traits (seven) and milking speed and milking temperament were analyzed by multiple trait models. Differences for conformation favoured Holsteins over crossbreds. There were no significant differences for milking speed or temperament between crossbreds and purebreds.
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