Survival is one of the most important traits in genetic improvement programmes in livestock. The objective of this study is to determine sex, inbreeding, and birth type effects as well as their interactions on birth survival in lambs of two breeds. Records of 6356 Polish Merino (PM) breed and 9143 Wielkopolska sheep (WS) were taken into the analysis. Relationships between survival and three binary variables (sex, inbreeding, type of birth) were estimated by the use of logistic regression. Interactions among these variables were also included in the model. Thus, the odds ratios and synergy coefficients were estimated. Lowest birth mortality was registered for inbred females from single birth. Differences in survival between the studied breeds were observed. Negligible single effects of sex, inbreeding and birth type for PM were estimated, whereas for WS these effects were significant (P<0.01). Opposite dependencies were obtained for interactions among these variables. In the case of PM, synergy between birth survival and joint effects of sex-inbreeding, sex-birth type, sex-inbreeding-birth type were highly significant, but for WS only inbreeding-birth type interaction was considerable. Hence, a generalisation of the obtained results seems to be difficult: they exhibit a very complex background of lamb survival.

Twenty goats of White Improved breed were divided by analogue method into four groups and fed a basal diet consisting of different roughages (maize silage, sugar beets and meadow hay) and a concentrate containing soyabean and rapeseed meals. Animals from individual groups were supplemented with 0, 1.5, 3 and 4.5 g/d of rumen protected methionine (Smartamine™ M).No significant differences in milk yield and composition were observed. However, a trend in the daily milk and fat yields as well as in milk protein content and yields were found in goats with the increase of rumen protected methionine up to 3 g/d. The amino acid composition of milk protein did not differ significantly among groups.

Abstract. A total of 307 lactations of ewes from synthetic line (13/16 East Friesian Milk Sheep, 3/16 Polish sheep breeds) were invesstigated. Ewes were milked after weaning, starting on the 60th day of lactation, for the period of our months. Milk recording was conducted using the A30 scheme during the morning and afternoon milkings. Twenty one simplified milk recording schemes were investigated, taking into account the data from 4 or 6 control milkings, and estimating the differences between milk production, protein and fat contents on the basis of the simplified and the A30 methods. The accuracy of the methods to estimate milk (protein, fat) yields was verified using the pairwise test. Among the tested 4-measurement methods, the most useful – in terms of the accuracy of milk, protein and fat yield estimations – were models, in which milk recording is conducted once a month, only in the morning or afternoon. The application of such methods does not result in the deterioration of accuracy of milk recording for sheep and makes it possible to lower the costs connected with recording by approximately 50 %.