Feeding System Considerations for Manufacturing Dairy Products
As dairy producers look for avenues to increase profit from the milk produced on their farm, some options include implementing a specific production system (e.g., organic), focusing on a particular product attribute that adds value for marketing, or manufacturing a new product. For example, consumers may pay a higher price for milk that is marketed as grass-fed. Other products may also be manufactured from that milk and marketed with a grass-fed label.
It is important for producers and consumers to understand that, as a result of the production system, the finished products manufactured may have varying compositional and functional properties among different types of operations or differ seasonally within an operation. Value-added dairy producers and producers selling to a processor may want to consider where their milk will end up and how it will be received when decisions are made about farm management and feeding practices.
Milk quality begins on the farm with healthy animals, clean, comfortable housing, good milking practices, routine milking equipment maintenance and sanitation, proper milk cooling, and feeding practices. Yes, feeding practices play a role. Many factors that could have implications on product quality may be tied to farm management's decisions surrounding feeding and the composition of the ration. For example, decisions about the amount of grazing, the composition of the ration, or incorporation of byproduct feeds can impact the composition of the finished product.
The properties of milk differ between what is produced by cows on a pasture-based system and that which is from cows fed a total mixed ration (TMR) indoors. Magan et al. (2021) summarized observations according to milk composition, a cheese food matrix, and a butter food matrix. Notable characteristics included a yellow color of butter and cheese made with milk from pasture-based systems and a white color of cheese and butter made with milk from indoor feeding systems (e.g., TMR feeding, component feeding, supplementation). Product texture was reported as softer for cheese and butter from grass-based systems when compared to the products from indoor systems, resulting in lower melting temperatures for cheese and greater spreadability for butter from grass-based systems.
Feed management practices can lead to flavor defects in milk through absorption by inhalation or digestion by the cow (Dairy Practices Council, 2023). For example, off-flavors can result when cows are fed silage immediately prior to milking and the ventilation is inadequate in housing areas. The flavor issue can usually be resolved by altering the timing of feeding and ensuring proper ventilation. The Dairy Practices Council Guideline 38 provides a list of feed ingredients that may cause off-flavors in milk:
- fermented silage or haylage
- alfalfa
- clover hay
- wet distiller's or brewer's grain
- green barley or rye
- cabbage, turnips, and beet tops
- musty hay or silage
- wild onions
- weeds (including mustard, garlic, and ragweed)
Some flavor defects can be strong and easily detected by consumers. Producers should try to make gradual changes in feeding practices to reduce the chance of off-flavors resulting in the milk, as the differences in flavors will be less abrupt and less likely to be perceived by the consumer.
Ensiled forage provides a way to preserve crops for feeding at a later time through fermentation. Since microorganisms are instrumental to the fermentation process, there can be noticeable changes in products from milk produced by cows that have been fed silage, as demonstrated by sensory analysis of cheese (Giello et al., 2017). Other researchers have reported differences in sensory analysis of cheese when comparing types of silage in the diet or comparing silage to hay in the diet. Defects in cheese due to gas produced by spore-forming bacteria have been linked to poorly preserved silage (Driehuis et al., 2016).
While nutritional analyses of finished dairy foods according to feeding practices have been conducted, the information is beyond the scope of this article and is not included. For processors and producers, understanding the properties of dairy food, whether it is milk, cheese, or butter, and the influences on those properties from on-farm practices are important for ensuring the highest quality finished product. The result will be a more positive experience for consumers when the dairy products they purchase have the expected taste and appearance.
References
Dairy Practices Council. 2023. GL 038: Identifying and preventing off-flavors in milk and milk products. 3nd rev. ed. Keyport, NJ.
Driehuis F, Hoolwerf J, Rademaker JLW. 2016. Concurrence of spores of Clostridium tyrobutyricum, Clostridium beijerinckii, and Paenibacillus polymyxa in silage, cow faeces and raw milk. Int Dairy Journal 63:70-77.
Giello M, La Storia A, Masucci F, Di Francia A, Ercolini D, Villani F. 2017. Dynamics of bacterial communities during manufacture and ripening of traditional Caciocavallo of Castelfranco cheese in relation to cows' feeding. Food Microbiology 63:170-177.
Magan JB, O'Callaghan TF, Kelly AL, McCarthy NA. 2021. Compositional and functional properties of milk and dairy products derived from cows fed pasture or concentrated-based diets. Compr Rev Food Sci Food Saf 20:1-32.
