Method of selecting cows and bulls for resistance to mastitis by the number of somatic cells in milk

The results of a study on the development of a method for selecting cows and bulls for resistance to mastitis by the number of somatic cells (NSC) in milk are presented. During the work, 8452 individual samples of milk from the Ayrshire cows were examined. The statistical-biometric parameters of the NSC in Ayirshire are determined. The average absolute NSC (ANSC) in milk of cows is low (189.8 thousand/cm³).However, it has a very high variability (289.1%) with a huge limit (from 2.0 to 9999.0 thousand/cm³). The frequency of cows’ distribution on this feature is characterized by a large positive asymmetry, the arithmetic mean ( Х ) is much larger than the median (Me), which in turn is larger than the mode (Mo). It does not meet the criteria for normal distribution and excludes the possibility of using this indicator in animal selection. The transformation of ANSC into scores based on the binary logarithm made it possible to obtain a distribution of cows close to normal, to ensure the homogeneity of its variance in different samples (lactation, among the cows of the herd, among the daughters of bulls, etc.). Therefore, scoring the number of somatic cells is suitable for classifying animals and developing criteria for evaluation and selection for resistance to mastitis. The procedure for selecting, processing and using information on somatic cells for breeding purposes is presented. A scale for estimating bulls and cows on the number of somatic cells in milk was developed and examples of the scale use are given. Bulls (according to daughters) and cows with an score of 3.9 or less are certified as highly resistant and can be used without restrictions; 4.0-4.9 points - a normal level of resistance and small restrictions in use; 5.0-5.9 points - resistance below the average level and use in the commodity group of the herd; 6.0 points or more - low resistance, in which cows and bulls are subject to culling.

somatic cells of milk, resistance to mastitis, score of somatic cells, bulls and cows rating scale, Ayrshire breed

1. Баарс З. Профилактика оправдывает себя. / З. Барс // Новое сельское хозяйство. - 2000. - № 2. - С. 30-32.

2. Другакова В. А. Организационно-технологические приемы управления качеством молока в молочном скотоводстве: Автореферат дис. … канд. с.-х. наук. Горки, 2013. 22 с.

3. Колчев А. Влияние концентрации соматических клеток на качественные и технологические свойства молока / А. Колчев, О. Сыманович // Главный зоотехник. - 2010. - № 3. - С. 27-30.

4. Самарина Е. А. Влияние полноценного кормления на качество молока / Е. А. Самарина // Клевера Нечерноземья. Сайт Кировского областного государственного бюджетного учреждения «Центр сельскохозяйственного консультирования «Клевера России» / 06.11.2011. [Электронный ресурс]. Режим доступа: http://kleverkirov.ru/ - (09.04.2016)

5. Dürr J. W. Milk losses associated with somatic cell counts per breed, parity and stage of lactation in Canadian dairy cattle / J. W. Dürr, R. I. Cue, H. G. Monardes, J. Moro-Vendezb, K. M. Wade // Livestock Science - 2008. - 117 - P. 225-232.

6. Hand K. J. Milk production and somatic cell counts: a cow-level analysis / K. J. Hand, A. Godkin, D. F. Kelton // J Dairy Sci. - 2012. - Vol. 95, 3 - P. 1358-1362.

7. Rudolphi B. Einfluss der Zellgehalte der Milch auf die Milchleistung von Kühen / Züchtungskunde. - 2004. - 76, (6) - S. 466-474.

8. Bovenhuis H. Selectie op Ret melkcelgetal bij tweede en volgende lactaties mogelijk / H. Bovenhuis, H. C. M. Heuven, R. D. Politiek // Veeteelt. - 1987. - 5 - P. 494-496.

9. Emmanuelson U. Genetic Parameters for clinical mastitis, somatic cell counts, and milk production estimated by multiple-troit restricted maximum likelihood / U. Emmanuelson, B. Danell, J. Philipsson // J Dairy Sci. - 1988. - Vol. 71, 2 - P. 467-476.

10. Heuven H. Inheritance of somatic cell count and its genetic relationship with milk yield in different parities / H. Heuven, H. Bovenhuis, R. Politiek // Lives. Prod. Sci. - 1988. - 18, 2 - P. 115-127.

11. Shook G. E. Selection of somatic cell score to improve resistance to mastitis in the United States / G. E. Shook, M. M. Schutz // J Dairy Sci. - 1994. - Vol. 77. - P. 648-658.

12. Pösö J. Finland. The pioneer of the recording and breeding for health traits / J. Pösö // Presentation summary. Word Ayrshire Congress 2008. Finland. Seminar 2. - 2 p.

13. Ali K. A. An optimum transformation for somatic cell concentration in milk / K. A. Ali, G. E. Shook // J Dairy Sci. - 1980. - Vol. 63. - P. 487-490.

14. Dekkers J. C. M. Genetic improvement of resistance to mastitis of Dairy cattle with special emphasis on somatic cell count / J. C. M. Dekkers, B. A. Mallard, K. E. Leslie // J Dairy Sci. - 1994. - Vol. 77. - P. 616-618.

15. Kehrli M. E. Factors affecting milk somatic cells and their role in Realth of the bovine mammary gland / M. E. Kehrli, D. E. Shuster // J Dairy Sci. - 1994. - Vol. 77. - p. 619.

16. Zhang W. C. Adjustment factors and genetic evaluation for somatic cell score and relationships with other traits in Canadian Holsteins / W. C. Zhang J. C. M. Dekkers, G. Banos, E. B. Burnside // J Dairy Sci. - 1994. - Vol. 77. - p. 659.

17. Shultz M. M. Genetic parameters for somatic cells, protein and fat in milk of Holsteins / M. M. Schutz, L. B. Hansen, G. R. Steuernagen, J. K. Reneau // J Dairy Sci. - 1990. - Vol. 73. - p. 494.