Milk is composed of water, lactose, fats, protein and minerals and vitamins and is influenced by breed, genetics, stage of lactation, age, nutrition and health status
- Breed – generally, the high production breeds such as Holstein tend towards lower milk solids than the lower production breeds such as Jersey or beef breeds.
- Genetics – within breeds selection of sires with high solids percentages is critical to maintain herd milk composition.
- Stage of lactation – fat and protein concentration generally increases towards the end of lactation.
- Age – milk fat and protein both decrease with subsequent lactations.
- Nutrition – lactose is the driver of milk volume and its percentage is independent of nutritional influences. Butterfat percentage is dependent on forage intake, ingested fats and bodyweight loss. Protein percentage can be manipulated by varying concentrate feed level, starch concentration and amino acid balance.
- Health status – udder health is critical to maintaining optimum milk composition while general cow health and energy balance play an important role in milk quality.