Implications of changes to primary production and management practices in pasture-based dairy systems, on the compositional and processing properties of milk and Cheddar cheese quality
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Date
2025-10-15
Authors
Page, Richard M.
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University College Cork
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Abstract
This thesis considers the effects of some key primary production and management practices on the compositional, technological and ripening properties of Cheddar cheese. In Ireland’s predominantly pasture-based dairy system, about a third of all milk is used for cheese production. As dairy farming practices evolve (e.g., adoption of practices to enhance sustainability of primary milk production), the composition of milk can change, with implications for dairy products made therefrom. Developing a deeper understanding of how farm-level decisions influence cheese quality is therefore of scientific and commercial relevance.
The impacts of dairy production practices on the processing of milk into cheese were initially explored through a review of the literature. Various practices, both intrinsic and extrinsic to the dairy animal, were considered in-turn. Due consideration was also given to interactions taking place within the dairy food system, because primary production practices impact on each other, making it a highly complex system. Substantial evidence is available to suggest that some changes in production practices can be made without adverse impacts on cheese quality. The experimental chapters of this thesis then contribute to this evidence-base by examining pertinent research gaps, improving our understanding of the influence of milking frequency, pasture type, and cow breeding and genetics on cheese biochemistry.
Twice-a-day (TAD) milking is most commonly used within Irish pasture-based systems, and the impact of milking frequency on cheese production was explored by contrasting TAD with once-a-day (OAD) milking. Most notably, OAD milking yielded significantly more cheese from a given volume of milk compared to TAD, suggesting a possible increased economic value for OAD milk within cheese manufacturing. The OAD strategy also resulted in cheese that was significantly more yellow, a difference confirmed to be associated with significantly higher β-carotene content, β-carotene being both a pigment and pro-vitamin A. Consumers often favour more yellow dairy products, and increased β-carotene concentrations could provide nutritional benefits (supporting iron metabolism, skin and mucous membrane function, vision and the immune system).
Pasture-type was investigated through comparisons of milk and cheese derived from multispecies swards (MSS) and perennial ryegrass (PRG) diets. Milk compositions were found to be broadly similar, but MSS milks had significantly higher protein content. Significantly higher actual cheese yields (Ya) resulted from MSS grazing as compared to PRG, at 11.13 and 10.58%, respectively. For many investigated attributes, cheese obtained from the differing pasture diets were broadly comparable. These novel findings provide assurances that a biodiverse MSS strategy can be adopted while maintaining Cheddar cheese quality. The increased cheesemaking efficiency suggested through increased cheese yields could also offer an opportunity for manufacturers.
Investigations into crossbreeding compared differences arising when using Jersey-Holstein-Friesian (JFX) milk compared to Holstein-Friesian (HF) milk in the production of Cheddar cheese. The JFX milk had higher protein and fat content, but no statistically significant differences in set-to-cut time or cheese yield resulted. Cheese produced from both breeds was broadly comparable, but JFX derived cheese was significantly more yellow in colour. These intrinsic aspects of primary production were then explored further through investigations into genetic polymorphism of κ-CN, using milk collected according to the following treatment groups: HF with AA κ-CN (HF-AA), HF with AB κ-CN (HF-AB), and JFX with AB κ-CN (JFX-AB). On average, HF-AA milks had lower fat, protein and casein contents, smaller fat globule size, higher pH and larger casein micelle size compared to HF-AB and JFX-AB milks. The HF-AA treatment was associated with poorer rennet coagulation properties and lower cheese yields compared to HF-AB and JFX-AB. The highest cheese yields and fastest coagulation times were associated with the JFX-AB treatment. These findings suggest crossbreeding can be combined with the selection of appropriate genetic variants to achieve improved production trait outcomes.
Considered collectively, these findings advance our understanding of how decisions on the farm can influence the processing performance of milk obtained from Irish pasture-based systems, and the key quality attributes of cheese made therefrom. When milking frequency, grazing system and breeding selection strategies are applied appropriately on the farm, milk can be processed into Cheddar cheese without adverse impacts. Additionally, some areas have been highlighted where targeted use of these primary production strategies can enhance cheesemaking efficiency and product quality. The findings contained herein offer potential future benefits for stakeholders within Irish dairy food systems, in particular for processors and dairy consumers.
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Keywords
Dairy chemistry , Dairy primary production , Agricultural management practices , Cheese science , Sustainable farming , Dairy cow genetics , Dairy cow breeding , Milk processing , Dairy cow diets , Biodiverse grazing , Milking frequency , Multispecies swards , Once-a-day milking , Jersey-Holstein-Friesian dairy cows , Dairy cow crossbreeding strategies , Kappa casein genetics , Dairy science , Sustainable dairy , Milk attributes , Cheese attributes
Citation
Page, R. M. 2025. Implications of changes to primary production and management practices in pasture-based dairy systems, on the compositional and processing properties of milk and Cheddar cheese quality. PhD Thesis, University College Cork.