Abstract
Objective of this study was to calculate the variability and heritability of type traits in the nucleus herd of bull dams by using the linear method of evaluation, and to determine their importance in selection of cattle. Study included 127 Holstein-Friesian cows selected as bull dams on cattle farms of PKB Korporacija, Belgrade. By applying the Least square method, main variationstatistical parameters were calculated: arithmeitc mean, standard deviation, variation coefficient, standard error and variation range. Bull dams of Holstein- Friesian breed had average milk production of 10245.98 kg, with variation range from 6514 kg to 13251 kg. Average milk fat yield was 361.95 kg, and milk fat content 3,53%. Average values for type scores of Holstein-Friesian bull dams were: rump height 5.40, chest width 7.09, body depth 7.38, rump position 5.39, rump width 6.55, dairy form 7.35, rear legs set (rear view) 5.22, rear legs set (side view) 5.28, hoof angle 5.27, fore udder 6.65, front teats placement 5.43, teat length 4.76, udder depth 6.96, rear udder height 7.13, suspensory ligament 7.08 and rear teats placement 5.89. Also, heritability coefficients and errors were calculated for all milk and type traits. Type and body development scores are very important indicators of production ability of cows, their potential to consume sufficient quantities of food, produce high quality milk from the technological aspect, reduce the use of energy in production and remain as long as possible in exploitation.
Highlights
Linear type traits are basis of contemporary classification systems, and represent foundation of all systems used in description of dairy cattle
How will the genetic progress realized in the nucleus herd be achieved in the rest of population depends on several factors among which the most important are the complexity of the breeding program, bio-economical characteristics of traits, level of the selection intensity, remount percentage, duration of the generation interval, etc
Studies indicate that linear type scores should be included in total evaluation of the breeding value of animals, and gain complete insight into genetic superiority, especially in case of breeding bulls
Summary
Linear type traits are basis of contemporary classification systems, and represent foundation of all systems used in description of dairy cattle. Linear classification is based on measures/measuring of individual type traits instead of giving opinion. Body development and type are very important indicators of production abilities of cows, their potential to consume sufficient quantities of food, produce high quality milk from the technological aspect, reduce the use of energy in production and remain as long as possible in production giving a larger number of offspring (Pantelić et al 2009). Stojić et al (2002) state that in linear type scoring of Black and White cattle 14 traits are included, 6 are body development traits and 8 are udder traits. For following 4 traits: rump position, rear legs set, udder balance and teat size, this score is preferable. For remaining traits higher score value is preferable
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