Heifer Mastitis: Prevention is the Key!

The ultimate goal for any heifer management program is to develop a healthy adult cow that produces high-quality milk. This success depends on how heifers are managed from birth to first calving. Mastitis is considered one of dairy cows' most significant and costly diseases, resulting in decreased production and profitability.

Mastitis in heifers is rarely detected before calving, but few farms actively look for an infection before the animal calves. Subclinical mastitis can be challenging to detect because the milk appears normal, but a high somatic cell count is present. It is recommended that all producers use the California Mastitis Test (CMT) on fresh cows to detect mastitis in each quarter. The CMT provides an inexpensive option for detecting mastitis early and provides the most accurate results 5 days post-fresh. Producers also have other options available to them to detect mastitis. Microbiological examination of milk samples may be obtained from suspect quarters to determine the type of bacteria with which each quarter is infected. This exam can be more time-consuming than CMT but provides a more in-depth evaluation. With increased technologies, culturing on farms has become more prevalent in Pennsylvania, and costs have significantly decreased.

The highest risk factor for developing heifer mastitis can be exposure to mastitis-causing organisms. The environment in which heifers are housed year-round can play a significant role in the exposure. Heifers should be housed in a clean, dry environment with sufficient amounts of bedding. Animals with manure cover on the legs and udder area will experience increased mastitis at freshening. All heifers should be treated to the same clean environment as the milking herd. These animals are the farm's future and will soon be relied upon to provide high production levels to keep dairy farms profitable.

A second risk factor contributing to heifer mastitis is feeding waste milk to calves. This practice should be discouraged unless milk can be pasteurized before feeding. The exact mechanism that the organism is transferred to the udder is unknown. Still, it is likely related to the colonization of the teat skin and inner thighs with mastitis-causing organisms. Studies have shown that milking herds with a high incidence of mastitis also have an increased incidence of heifer mastitis.

Prevention of mastitis is based upon reducing exposure to mastitis pathogens and enhancing the ability of the heifers' immune system to respond. Prevention of mastitis in heifers includes the following strategies:

1. Controlling mastitis in the existing adult herd; contagious mastitis is more likely to spread if there is a high incidence of mastitis on the farm.
2. Use of individual hutches for pre-weaned calves to prevent suckling.
3. Feed milk replacers or pasteurized milk rather than waste milk.
4. Control flies; this is especially important in the upcoming months.
5. Milk fresh heifers first using clean milking equipment.
6. House heifers in well-bedded areas that are clean and dry.
7. Consider implementing a heifer mastitis vaccination program.

Remember, heifers are the future of your dairy farm. Introducing healthy, viable heifers into the milking herd will help increase productivity and profitability.