Body growth and haematological profile of heifer calves sired by a bull or its clone

The aim of this paper was to compare welfare-related aspects of the female progeny of a bull sire with that of its clone. Sixteen Friesian female calves, 9 daughter from a tested bull (BULL) and 7 from its somatic cell nuclear transfer clone (CLON) were monitored from birth to 36 wk of life. Body weight (BW), wither height (WH), and heart girth (HG) were measured: at birth, 4, 8, 12, 16, 20, and 24 wk of age. Blood samples were taken from jugular vein at 24-48 h, 1, 2, 3, 4, 8, 12, 16, 20, 24, and 36 weeks of age, to be analysed for haematological profile and blood glucose concentration. At the same time, rectal temperature (RT) was recorded. Data were evaluated using a mixed model, taking into account the repeated measures in time on the calf. For each variable, different covariance structures were tested, choosing the best according to the Akaike’s Information Criteria. Significant was set at P<0.05, and a trend was considered for P<0.10. At the end of 24 wk, CLON daughters were smaller in WH than BULL daughters. Around 20 wk of age, a trend in BW differences (with CLON daughters lighter than BULL daughters) was also confirmed from difference in HG. There were no differences in RT due to sire effect. Blood glucose decreased in both groups during the first 4 wk of life; at birth, only a trend for higher blood glucose in CLON daughters was recorded. Total leukocytes count did not differ between progenies. Circulating lymphocytes had a trend to be lower in CLON than BULL daughters. The neutrophil:lymphocyte ratio had a trend to be higher in CLON than BULL calves. No difference was demonstrated for erythrocyte features, whereas mean platelet volume had a trend to be lower in CLON than BULL progeny. From these results, there is no difference between progenies from BULL and CLON that may suggest welfare problems in the first 6 mo of life.