Identification of factors affecting colostrum quality of dairy Lacaune ewes assessed with the Brix refractometer

In this Research Communication we assessed factors affecting colostrum quality of dairy Lacaune ewes using the Brix-refractometer. Colostrum from 536 lambings from one commercial intensive dairy Lacaune farm were analysed for the following factors with potential influence in colostrum quality: (1) ewe parity (n = 84-132), (2) length of previous dry period (PDP) (n = 23-214), (3) age at first lambing (AFL) of primiparous ewes (n = 9-88), (4) lambing season (n = 192 or 344), and (5) year (2011-2013, n = 142-203). Parity significantly affected colostrum quality, with primiparous ewes showing the highest Brix refractometer values (22.6 ± 5.6%, P < 0.0001), though values were similar among multiparous ewes. PDP length also significantly affected colostrum quality: ewes with the shortest PDP showed the worst quality (16.8 ± 4.2%, P < 0.0001), with quality gradually rising with PDP length. Colostrum quality was significantly higher in 2011 (21.0 ± 5.2%) than in 2012 or 2013 (P < 0.0001); this likely reflects the several-fold greater proportion of animals with long PDP in 2011. In contrast, neither AFL nor lambing season significantly affected colostrum quality. These results suggest that parity and PDP length can substantially affect ovine colostrum quality of dairy ewes under intensive management conditions and they further show the usefulness of the Brix refractometer for providing a rough estimation of colostrum quality on-farm. However, further studies are needed to determine a validated cut-off Brix value for identifying good-quality colostra in ovine species.