The human factor

PARAMETERS IN MILK QUALITY AND MASTITIS

FORESTRIPPING

In dairy cows, immediate attachment of the milking unit will allow for the harvest of the cisternal milk fraction which amounts only to 20 % of the milk in the cow’s mammary gland. The remaining 80 % of milk is stored in the alveoli and not readily available until the activation of the milk-ejection reflex (Bruckmaier and Blum, 1998). Milk ejection is therefore necessary to optimize timely milk removal (Bruckmaier and Wellnitz, 2008) and fat composition (Ontsouka et al., 2003). When the cow enters the milking barn, the milk is distributed throughout the mammary gland in the milk producing cells (alveoli). Milk let-down is a normal process that forces the milk from these cells into the mammary gland cistern so the milk can be harvested. Fast, complete milk removal depends on a good let-down.

The intensity and duration of stimulation may have an impact on the amount of oxytocin released (Weiss, 2003). Increasing the stimulation time from 0 to 120 s did not affect milk yield. However, the enhanced stimulation increased the milk flow rate and decreased the milking time. This could have a significant effect on the health of the teat ends as well as the number of cows milked per hour (Gorewit and Gassman, 1985). Cows well primed 60 to 90 seconds before milking will milk faster, have less udder irritation, have a more constant production, produce more milk and are more profitable (Fig. 3).

Forestripping is defined as the presquirting of milk from each quarter to break the seal in the teat canal and to check for abnormal milk.

Forestripping will also clean the teat end of debris and will stimulate proper milk let-down. In addition, milk in the canal and at base of the teat has an elevated somatic cell count (SCC) and

3 The milking routine and its effect on milk quality

Figure 3. A proper premilking routine will adequately stimulate milk letdown and speed milking.

bacterial count compared to milk in higher parts of the udder. Forestripping will allow for the removal of this milk, thus reducing the SCC in the bulk tank and the potential to infect healthy cows milked with the same machine. Gently strip the teat 2 to 3 times and check for abnormal milk.

DRYING AND ATTACHING THE MILKING UNITS

The teats should be dried completely with a single towel (Fig. 4). It is important not to share towels among cows to avoid transferring mastitis-causing pathogens from one cow to another. No water should collect on the teat end after adequate drying. Attention should be paid to any water that is being used to clean the parlor, as it should not splash the teat ends.

Incomplete or inadequate drying can lead to outbreaks of environmental mastitis and lower quality milk.

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