Effects of full-time v. part-time grazing on seasonal changes in milk coagulation properties and fatty acid composition.
For this research communication our objective was to investigate to what extent milk coagulation properties and milk fatty acid (FA) composition were affected by different feeding systems, season and their interaction. Eighteen cows in total were subjected to one of three different feeding system treatments: full-time grazing or part-time grazing combined with indoor feeding of fresh grass with low or high concentrate supplementation. Milk was sampled in spring, summer and autumn. Milk coagulation time was 15.0, 19.0 and 17.7 min, coagulation dynamics 1.67, 3.41 and 1.79 min, and curd firmness 52.7, 32.4 and 47.0 mm in spring, summer and autumn, respectively. Thus, milk coagulation properties of the milk were lower during summer. There were strong seasonal effects on milk FA proportions, but there were not always changes with progressing season, or changes were different with respect to the impact of the feeding systems (system × season interaction). The milk fat was favourably rich in oleic acid, conjugated linoleic acid and α-linolenic acid and had a low n-6/n-3 fatty acid ratio in all systems. Factors like seasonal variations in grass composition and the energy balance of the cows were considered relevant for the milk FA composition. Overall, seasonal variations in milk quality were less pronounced with part-time grazing with fresh grass indoors as compared to full-time grazing without concentrate.
['Akert|Franziska S|FS|', 'Kreuzer|Michael|M|', 'Kunz|Carmen|C|', 'Reidy|Beat|B|', 'Berard|Joel|J|']
D000821:Animal Feed D000818:Animals D002417:Cattle D002611:Cheese D055598:Chemical Phenomena D004032:Diet D005227:Fatty Acids D005260:Female D006863:Hydrogen-Ion Concentration D008892:Milk D008894:Milk Proteins D006109:Poaceae D012621:Seasons
grazing milk coagulation properties fatty acid composition Concentrate supplementation dairy