Why stay vigilant?
In early lactation, new infections are more likely to show up as clinical cases, due to the types of the bacteria involved. That’s why we tend to be more diligent at spraying teats to prevent mastitis during this time.
As the lactation progresses, it’s important to stay focused – these infections tend to show as subclinical mastitis, which is harder to spot. Although these cases may only affect the somatic cell count, these new infections are of concern.
Infections due to minor types of bacteria can put the udder more at risk of infection by major pathogens, once cows are dried off. As we move towards using less antibiotics at dry off, it becomes even more important to reduce the mild infections picked up when cows are in milk.
Teat spraying’s ‘double hit’
Teat spraying has two main actions:
- Retain moisture in teat skin
Teat spray contains emollients that helps skin retain moisture and remain smooth and soft. Dry, rough teats are harder to keep clean, retain more bacteria on the surface, and are less able to withstand milking, leading to minor sores and teat damage. New Zealand research has found that, within two days of stopping teat spraying, the moisture levels in milked teats had dropped to levels normally seen in dry cows.
- Reduce bacterial numbers
Teat sprays can’t kill all bacteria on teats, but good application leads to lower numbers on teat skin. A study across five dairy farms (using an iodine-based product) found that cows not teat sprayed for a whole lactation had twice as many new infections, higher somatic cell counts and more teat damage than teat-sprayed herd mates (see Figure 1).
Manual vs automated teat sprayers
Some farmers prefer a simple, manually operated ‘garden sprayer’; others, a pressurised wand or an automated system. Aim for one that regularly achieves good coverage within the first few minutes after milking.
With hand-held devices, expect to use 15 to 20 millilitres (mls) per cow per milking. With pressurised wands or automated systems, expect to use 25 to 30 mls per cow per milking.
Myth: No need to teat spray after Christmas.
Busted: Bacteria remain present on teats at any time of year. Teat spraying is THE most effective measure to prevent new infections.
Learn more about teat spraying at dairynz.co.nz/dairy-stockmanship
This article was originally published in Inside Dairy December 2019