Once a calf is born, it is at immediate risk of picking up infections from the calving environment, the cow or any other animals in the same space. Therefore, it is best practice to remove the calf from the cow immediately after birth. Separation of the cow and calf at birth is good practice from a nutritional and disease prevention point of view. The dairy cow udder is often not anatomically suitable to feed correctly and many dairy cows have poor mothering ability. Such herd-health practices also helps to prevent diseases such as Johne’s in the calf or mastitis in the cow. Calves are moved to a clean, freshly bedded area in the company of other calves. This ensures that they can be fed the nutritious colostrum. Feeding the colostrum allows the farmer to ensure the calf is getting enough and in a more hygienic setting.
Lactation yield is the amount of milk produced by a cow over a full lactation cycle. A full lactation cycle is approximately 9-10 months in duration and can be divided into three sections; early, mid and late lactation, followed by a 2-3 month dry period. Lactation yield will vary greatly throughout these four periods. During early lactation a cow will typically produce 12-25 litres of milk/day, by mid lactation a cow will reach its lactation peak of approximately 35 litres of milk/day. A reduction in milk yield occurs during late lactation and finally when yields drop to 8-9 litres/day the drying off period commences. On average, a dairy cow can give up to 28 litres of milk/day. Factors affecting milk yield include breed (the Holstein Friesian breed produce the highest yield), lactation number (animals typically reach their peak yield at their 4th/5th lactation) and management factors (frequency of milking, nutrition).
Milk production in Ireland is split into two cycles: summer or winter – and cows only supply milk for one of these cycles (the majority are in the summer cycle while grass is growing). For example, the ‘summer cycle’ cow in Ireland is brought into pregnancy around May and continues to produce milk until the drying off period around October/November. This allows between two and three months of non-milking before calving and, once managed correctly, has no negative impacts for the cow or calf.
Nowadays, the majority of milk sold in Ireland comes in a plastic container or carton. The plastic containers are most commonly made from high density polyethylene (HDPE). This is an approved food contact material, which protects the food, is lightweight and recyclable. Milk cartons for refrigeration are mainly made from paper, in the form of cardboard, as well as thin layers of the same approved plastic, polyethylene. The European Food Safety Authority is responsible for monitoring exposure and safety with regards to food contact materials and based on the current risk assessment, polyethylene is approved as safe.