The effect of specialized dairy breeds on udder cistern size in Tsigai crossbreds

Abstract

Sonographic images of the ewe left and right udder cisterns using 2 methods (1 – from side, 2 – from bottom) were taken by means of two devices: an ultrasonograph Aloka 250 (3,5 MHz linear probe) or ultrasonograph SonoVet2000 (L2-5/170 CD linear probe). Length, width and area of each udder cistern were measured during milking period in years 2002 to 2008. The ewes of 5 genotypes (purebred Tsigai, purebred Lacaune, crosses of Tsigai with Lacaune and East-Friesian with genetic portion of specialized dairy breeds 25 %, 50 % and 75 %) were evaluated. According to measured traits, 640 and 752 sonograms from 200 and 231 ewes were taken using the method 1, and 470 sonograms from 163 ewes were taken using the method 2. Data were evaluated using REML methodology and MIXED procedure (software SAS/STAT). The effect of genotype showed the highest influence (P<0.001) on the length and area of the left and right udder cisterns. In purebred Tsigai ewes, the average areas of the left and right udder cisterns determined using the method 1 were 1413.1 ± 78.56 mm2 and 1400.4 ± 71.58 mm2 . These were significantly smaller in purebred Tsigai ewes than in purebred Lacaune ewes (2698.3 ± 78.62 mm2 and 2696.2 ± 71.47 mm2 , respectively; P<0.001). Mostly, the udder cistern areas were significantly higher in crosses than in purebred Tsigai ewes. The effect of parity using the method 1 was significant too. The average areas of the left and right udder cisterns determined using the method 1 were 1892.0 ± 84.08 mm2 and 1902.7 ± 77.39 mm2 in ewes at the first parity and 2231.9 ± 97.96 mm2 and 2315.0 ± 90.86 mm2 in ewes at the third and further parity. Our analyses showed that crossbreeding of TS with LC and EF considerably increases ewe‘s cistern size. This fact indicates that breeding goals in dairy sheep in Slovakia are being successfully followed.