Effect of lactation stage on the cheesemaking properties of milk and the quality of Saint-Nectaire-type cheese

Abstract

Two groups of eight multiparous cows with different calving periods (November or February) were managed in the same way during lactation. During four 4 week experimental periods distributed over 12 months, the cows were fed on a diet composed of hay and concentrate (70[ratio ]30) in a restricted and controlled amount which varied according to their lactation stage, so as to cover the animals' requirements correctly. The animals' average lactation stage varied according to period from 26 to 298 d. Milk from each group was processed on two occasions during each period to make Saint-Nectaire-type cheese; the cheesemaking conditions were the same throughout. Lactation stage had an important effect on milk fat, protein and calcium contents but not on the casein[ratio ]protein ratio or phosphorus content. The milk pH and the urea content were higher in late lactation. The calcium concentration of milk was higher in late lactation but the soluble fraction was higher in early lactation. Despite higher protein contents, the maximal firmness of the coagulum of late-lactation milk was not different from that of early or mid-lactation milks. pH was higher in cheeses from late-lactation milks compared with those from early and mid-lactation milks. Cheeses from early lactation milks were more yellow than the others and had a lower dry matter fat content. In sensory analysis the odour of cheeses from early and late-lactation milks was less pleasant than that of those from mid-lactation milks. Cheeses from late-lactation milks were more melting and less firm than those from early or mid-lactation milks. Their taste was more intense and more persistent. At tasting, they were less appreciated than the others. These differences were linked to increased proteolysis in the cheeses made with late-lactation milks.

Changes of physico-chemical characteristics, somatic cell count and curd quality during lactation and their relationships in Lacaune ewes

“…This result is in accordance with Coulon et al (1998). In our opinion, relatively balanced CQ throughout lactation were primarily associated with increasing of TP, casein and Ca contents, relatively stable pH and TA values, and finally also with low values of SCC.…”

Gene expression of six major milk proteins in primary bovine mammary epithelial cells isolated from milk during the first twenty weeks of lactation

“…Nevertheless, the highest total protein production was found, as described previously, during the first months of lactation (Friggens et al, 2007). The ratio of total caseins to whey proteins does not vary depending on the stage of lactation, reflecting no changes in the rates of synthesis for both main fractions (Coulon et al, 1998). Yet, relations between specific caseins differed depending on the stage of lactation (Kroeker et al, 1985;Çardak, 2009).…”

Relationships between ruminant management and sensory characteristics of cheeses: a review

“…The texture differences noted between cheeses issued from late-or middle-lactation milk can be related to increased proteolysis in late lactation, as shown by the increase in pH and γ -casein content in these cheeses [30]. This proteolysis is due to plasmin, whose activity increases in late lactation [11], especially when SCC are high [5].…”

“…Both concluded that the reduction in cheese quality noted at the end of lactation was greatly limited when feeding and SCC were well controlled. Coulon et al [30], working under controlled milk production and Saint-Nectaire cheese-making conditions, managed to totally single out the effect of the lactation stage, as monitored between 26 and 298 d (Tab. IV).…”