УДК 636.22/28.081.14 INFLUENCE OF UDDER DESCRIPTIVE LINEAR TRAITS ON COWS LIFETIME OF UKRAINIAN DAIRY BREEDS

Studies have been performed to determine the relationship between assessment of linear udder traits and lifetime of cows. Experiments were carried out in the herd of breeding farm AF "Mayak" Zolotonosha district of Cherkasy region on the number of cows of Ukrainian Red-and-White (URW) and Black-and-White (UBW) dairy breeds. Estimation of cows firstborn by conformation type was carried out according to the method of linear classification. It was found that cows with higher estimates for condition of udder morphological traits have a longer lifetime compared to animals rated lower score. The difference between cows, rated at one and nine score for trait of the front udder part attachment, was very significant and amounted 939 (URW) and 710 (UBW) days. The difference between the lowest and highest estimates on the basis of height rear udder parts attachment was 687 (URW) and 878 (UBW) days. Animals with an assessment for udder central ligament development below the average (1.4 score) were used from 1675 to 1832 (URW) and from 1535 to 1810 (UBW) days according to estimated breeds. Cows with an assessment of nine score differed by higher lifetime - 2377 days, exceeding cows with the lowest score at 702 days (URW) and 2322 days with reliable excess on 785 days (UBW). The difference between the average lifetime of cows estimated at nine score and with assessment of one score for udder depth was 618 days in cows URW and in UBW - 762 days. It has been proven that cows were used longer in the herd with estimates for front teats position from five to nine score, and a significant decrease in lifetime of cows began with an estimate for this trait from three to one score. Thus, assessment of cows Ukrainian Red-and-White and Black-and-White dairy breeds by the method of linear classification confirmed that the desired development of udder morphological traits was the key to long lifetime cows in modern technological conditions of milk production.

Since the level of linear traits assessment of cows influenced the indicators of their longevity, the task of our research was to study correlative variability between the assessment of udder morphological traits of cows Ukrainian Red-and-White and Black-and-White dairy breeds and their lifetime.
Materials and research methods. The experiments were carried out in the herd of breeding farm on reproduction Ukrainian Red-and-White and Black-and-White dairy breeds AF "Mayak" Zolotonosha district of Cherkasy region. Estimation of cows firstborn by conformation type was performed by the method of linear classification [21] according to the latest ICAR recommendations [31] at the age of 2-4 months after calving. Descriptive linear traits were estimated on 9-score scale. The average expression of trait was rated at five score. With biological deviations of trait towards minimum development, estimate decreased to one score, and, conversely, if the trait development approached to maximum manifestation, increased to nine score. Estimation results were processed by biometric statistic methods on PC according to formulas given by E. K. Merkuryeva [4].
Research results. The first and most important descriptive udder trait -strength of its front part attachment to the cow's abdomen (Fig. 1).

Fig. 1. Correlative variability of scoring descriptive type trait "front udder parts attachment" and cow's lifetime
The angle formed at the site of this connection was assessed. The highest score for development of this body part was received by an animal in which the udder was characterized by gradual transition front part glandular tissue to abdomen by connecting lateral ligaments with formation of an obtuse angle higher than 161° [8]. The strong udder attachment was usually characterized by good development of front part and had a bath-like shape and, according to scientific studies, significantly correlated with milk productivity [10,12,16,18,20]. In addition, the strong attachment of front parts prevented sagging of udder with age.
Indicators of scores for front udder part attachment ( Fig.  1) showed a relationship between this trait development and cow's lifetime of assessed breeds. The difference between cows, rated at one and nine score, was quite significant and amounted 939 (URW; P <0.001) and 710 (UBW; P <0.001) days.
The linear trait "height rear udder attachment" also performed a supporting function, not allowing the udder to fall with age. Desired body part development was estimated with the highest score. The difference between the lowest and highest scores on this trait, obtained from our studies in cows of experimental breeds, was 687 (URW; P <0.001) and 878 (UBW; P <0.001) days (Fig. 2).

Fig. 2. Correlative variability of scoring descriptive type trait "rear udder parts attachment" and cow's lifetime
The central ligament -next linear udder trait in cows of dairy cattle, which was associated with keeping it at the appropriate height. Highly situated udder above the ground made it easier to prepare for milking and prevented cooling and injury. A high udder position with a deep, strong, well-defined and highly raised central ligament -the desired trait development with assessment in 9 score. Histograms ( Fig. 3) showed that average cow's lifetime depended largely on the assessment level for "central ligament". Animals with estimate for udder central ligament development below than average (1-4 score) were used from 1675 to 1832 (URW) and from 1535 to 1810 (UBW) days according to the estimated breeds. Cows with assessment nine score differed a higher lifetime -2377 days, exceeding cows with the lowest score at 702 days (URW; P <0.001) and 2322 days with a significant excess by 785 days (UBW; P <0.001).
The location of udder bottom relative to the floor -very important technological trait. According to the method of linear classification, udder depth was estimated by distance between relatively conditional line drawn at the level of hock joint and udder bottom. As noted above, a deep, sagging udder will cause many inconveniences during machine milking. Will often be injured and more susceptible to disease of mastitis. Indicators of histograms ( Fig. 4) showed that cows with highly placed udder were significantly less exposed to these risks and used longer in the controlled herd. The difference between the average lifetime of cows with an assessment nine score and one score for udder depth was in cows of Ukrainian Red-and-White dairy breed 618 days (P <0.001), in cows of Ukrainian Black-and-White dairy -762 days (P <0.001). Teats that have been placed at the optimal distance, placed in the center of udder parts, directed vertically down, cylindrical or conical in shape -will best meet the requirements of machine milking [9]. A very close or very wide front teats position will not be the best this trait development. Diagram results showed that cows of both breeds were used for longest time in the herd of controlled farms with estimates for the front teats position from four to nine score. A significant decrease in lifetime in cows began with estimate for this trait from three to one score.
Conclusions. Estimation cows of Ukrainian Red-and-White and Black-and-White dairy breeds by the method of linear classification confirmed that the desired development of udder morphological traits -the key to long life of cows in modern technological conditions of milk production.