LINEAR EVALUATION OF HOLSTEIN BULLS BY THE EXTERIOR TYPE OF THEIR DAUGHTERS IN "OSTRIYKOVSKE" LLC
Authors: Cherniak N. H. , Cherniak N. S. 
Published: July 2023

Introduction. In the context of intensive milk production technologies, the dairy farming industry faces high demands on animal health, constitutional strength and manufacturability due to mechanization and full automation of production processes. Modern methods of breeding involve the creation of highly productive animals that are well adapted to the least costly production technologies, taking into account an objective assessment of their breeding qualities and the application of population genetics.

Materials and methods of research. The study was conducted based on the materials of primary breeding records in the farm "Ostriykivske" LLC, Kyiv region. Evaluation of the milk production of cows was carried out for 305 days of the last completed lactation on the basis of the database of the dairy farming management system (Intersel-Orsek). An eyeball assessment of the exterior of the firstborn heifers was carried out according to the instructions for boning in the modification of Y. P. Polupan and the method of linear classification by type. The exterior of the animals was studied by taking the main 17 measurements at 2–5 months of lactation.

The cow type was evaluated using two systems: a linear description of individual exterior traits; evaluation of complex traits on a 100-point scale. The total score was calculated based on complex traits, which in turn were based on linear descriptive traits. In the process of evaluating the animals, the results were recorded in the evaluation sheet for dairy and dairy-meat cows by body type, pre-recording the animal's identification number, nickname, date of birth, date of calving, and lactation number. A total of 114 first-born Holstein cows were evaluated at Ostriykivske LLC.

Research results In the herd of Ostriykivske LLC, the best score for the complex of traits was obtained by the daughters of the bull sire Lobby 101916210 of the Eleweishna 1491007 line (83.2 points), which corresponds to "good with a plus". The daughters of the bull sire Kingly 101409948 of the H. H. Starbuck 352790 line received the lowest score – 78.0. The lowest score for the complex of limb traits was observed in the daughters of the bull Sleman 7817774 of the Valiant 1650414 line (70.5 points), and the highest in the descendants of Lobby 101916210 – 79.3 points. The variability of scores for udder traits ranged from 76.2 points in the daughters of Tandem 9434213 to 80.8 points in the daughters of Lobby 101916210 with a difference of 4.6 points between these extreme variants.

In addition, the evaluated cows have undesirable development of certain appearance traits, such as additional teats, close proximity of the hind teats, rudiments behind the teats, underdeveloped udder lobes, and diseased limbs. Thus, the use of the linear classification methodology allows you to obtain information about the features of the body structure, identify the advantages and disadvantages of cattle.

Such quantitative traits as milk yield, milk fat and protein yield are economically important for dairy producers. The obtained results of the research show that the best score for the complex of traits (83.2 points) and the highest milk yield (milk yield – 10560 kg; fat – 3.92%; protein – 3.15%) are observed in daughters of the bull of the sire Lobby 101916210 of the line Eleveishna 1491007.65. It was found that the firstborn cows with the best type indices are characterized by high milk production. Selection of the best performers by linear evaluation by type for the repair of the dairy herd of firstborn cows will provide more functional reliability and high milk production.

Conclusions. Thus, the use of the linear classification methodology in dairy cattle breeding allows to objectively determine the characteristics of cows by type of appearance, and the existence of a relationship between milk production and group linear traits is the key to the effectiveness of animal selection by type of appearance.