The Relationships between linear type traits and milk yield of brown-swiss cows at Malatya Sultansuyu Agricultural Station

95 7. SUMMARY The aim of this study was to determine the relationships between final score, linear type traits (L T T) and milk yield of Brown-Swiss cows bred at Malatya Sultansuyu Agricultural Station. Final score of cows were given on a 100 grade scale. For L T T, a 50 grade scale was used for each of the below parameters; 1 - Stature, 2 - Body depth, 3 - Pelvic angle, 4 - Pelvic width, 5 - Dairy form, 6 - Rear legs (side view), 7 - Foot shape (angle), 8 - The placement of front teat (rear view), 9 - The attachment of front udder, 10 - Length of front teats, 11 - Udder depth, 12 - The height of rear udder (attachment), 13 - Suspensory ligament. In the study, the influence of the number of lactation (the number of birth given), grading year, grading season, the age of the animal and of the environmental factors on the final score and L T T were also determined. None of the factors had significant influence on the final score. However, the number of lactation had significant influence on pelvic angle, the placement of front teat, and on udder depth. The grading season influenced the the placement of front teat, pelvic width, height of rear udder, foot shape (angle), udder depth and on rear legs. Also, similar effects of grading year on dairy form, and pelvic width was statistically significant. The influences of age on body depth, pelvic width, dairy form, front udder attachment, udder depth, the length of front teat, and on suspensory ligament were significant. The level of significance in the above measurements varied between p<0.05 and p<0.001. grades on L T T varied significantly depending upon lactation stages. Only exceptions to the above findings were suspansor ligament and dairy form. The average final score in this study was 73.38 ± 0.30 and this value is a corercted average final score which takes some environmental factors into the consideration. Average grade points for L T T was 13.25 ± 0.58 for the shortest front teat length, and 36.48 ± 0.56 for the largest front teat lenght. For cows, milk yield for 305 days were 4000.80 kg. Heritabilities for L T T were 0. 14 ± 0.08 for lowest rear legs and 0.74 ± 0.14 for highest rear udder attacment. Heritability for milk yield were 0.29 ± 0.09.96 Phenotypic correlation between the final score and milk yield was - 0.01. Phenotypic correlations between final score and L T T were - 0.16 for the lowest rear legs and 0.30 (p<0.001) for the highest front udder attachment. Phenotypic correlations between 305 days milk yield and pelvic angle, front udder attachment and udder depth were - 0.26 (p<0.05), 0.09 and 0.09, respectively. The lowest phenotypic correlation between the L T T was obtained from dairy form and body depth (0.46, p<0.001) and the highest from the pelvic width and body depth (0.5 l,p<0.00 1). Genetic correlations between L T T and 305 days milk yield and udder depth and stature were - 0.29 and 0.71, respectively. High genetic correlations between L T T were noticed. Of these correlation the one between body depth and the length of front teat was 0.96. Correlation between the length of front teat and front udder attachment was - 0.83. Genetic correlation among ot her traits were between these values. In conclusion, this study may indicate that in selection directed towards increasing milk yield of Brown-Swiss cows bred in Sultansuyu Agricultural Station, genetic correlations between some L T T and milk yield showed that these characteristics may use for selection directed towards increasing milk yield. However, similar studies carried on larger number of cows may also be useful.