THE NUMBER OF SOMATIC-CELLS IN MILK IN RE LATION TO SOME BREEDING FACTORS

Somatic cell counting (SB) indicates a health state in the herd and it is an indicator for the dairy industry of technological value of milk . Somatic cell count was during a year in the bulk milk samples in 212 herds. Total 3,219 samples were analyzed. The herds were composed of combined and dairy breeds of cattle, i.e. Bohemian Spotted breed, impr oved breeds Ayrshire and Red Holstein (Red and White breed) and Black and White breed with various degrees of transfer crossing from Bohemia n Spotted breed with a share of Holstein breed (Black and White breed) . Somatic cell count (SB) content was first measured (three months) by electronic cell counter, type Coulter Counter, Industrial D (produced by the company Coulter Electronic Ltd., England). Further measurement was conducted on the apparatus Fossomatic 90 (A/S N. Foss Electric, D enmark), operating on the principle of optoelectronic determination. A n average value from average of 212 herds represented 241,000 +/- 83,0 00 per 1 ml for the area under study. Fig. 1 shows the share of bulk m ilk samples in the grade up to 300,000 somatic cells per 1 ml and up t o 500,000 somatic cells per 1 ml. It is evident that the region is on a good level and that economic pressure forces the farmers to reduce s omatic cell counts below 300,DOO per 1 ml. In view of variants of bree ding factors the homogenity test (chi2) was used to examine conditions in bulk averages of somatic cell counts marginal frequency ranges (< xBAR - s(x), > xBAR + s(x)). The breed group had a significant effect on somatic cell content (P < 0.01); Black Pied cattle exhibited a high er somatic cell count against Red Pied breed. It follows from Tab. I t hat the production region had no significant effect on the counts of s omatic cells. The effect of the level of average efficiency was record ed as statistically significant (P < 0.0005). The shift to higher soma tic cell counts is evident in herds with lower efficiency. The lactati on parity (P < 0.0005) was manifested as an important factor where low er somatic cell counts were detected in first calvers An introduction of grass into feed ration had a significant effect (P < 0.05) - and he rds with grass manifested higher counts of somatic cells. The predomin ance of single type of silage and round-the-year incorporation of maiz e silage to the feed ration had no significant effects on somatic cell counts. Somatic cell count was not influenced statistically significa ntly by disinfection prior to milking, nor after milking, however, the result may be affected by random effects. A significant relation (P < 0.10) to somatic cell count was found for service period from indicat ors of reproduction. In extension of service period over 90 days, the shift to higher somatic cell values was recorded. The first A. I. gest ation percentage and A. I. index had no significant relation to the so matic cell count, but a shift to higher cell counts was visible in cas e when A. I. index was higher than 1.7.