Factores que afectan el score materno en ovejas Merino Australiano

This study was carried out at the Experimental Station of the Faculty of Agronomy in Salto (EEFAS), with the data obtained from the lambing of the breeding Flock from 2015 to 2018. The objective was to evaluate the different factors that could be affecting the maternal score of the sheep. Data from 252 Australian Merino ewes were used, and 467 maternal score records were obtained; 67 records in 2015, 150 in 2016, 105 in 2017 and 145 in 2018. At the time of birth, information was recorded for both the lamb and the ewe, including the maternal score on a scale of 1 to 6. The factors analyzed were year of registration (1 to 4), age of the mother (2 to 10, years grouping the oldest ewes in ≥7 years), type of birth (single or twins), sex of the offspring (male, female or male/female, in the case of mixed-sex twins) and lambing group (group 1 = IATF lambing, group 2 = lambing from the first post-IATF estrus and group 3 = lambing from the second post-IATF estrus). The factors type of lambing, sex of the offspring and lambing group did not significantly affect the maternal score, so they were removed from the analysis. The factors that did affect the maternal score were year of registration (P=0.0087) and age of the mother (P=0.0616), increasing the probability of finding higher maternal scores as the age of the mother increased mother and with the increase in the years of registration. It can be affirmed that the experience of successive births by the ewe and the experience accumulated in management in general affect maternal behavior, and therefore the establishment of the maternal-filial bond. In the four years of registration, the maternal score improved, regardless of the number of sheep and the age structure of the flock in each year, which suggests that there was an improvement in management.