This month many herds will begin spring calving and a particular area to focus on to prevent health problems in cows and calves is the calving yard.
The hygiene of the calving yard is vital to prevent cows contracting new mastitis infections as their udder develops ready for lactation.
It is also where calves are most likely to pick up infections causing scour, such as cryptosporidium, rotavirus, coronavirus and E. coli.
The last two to three weeks of the dry period pose the highest risk in the whole lactation cycle for a cow to pick up a new infection in her udder. Clinical mastitis cases in the first 30 days of lactation are most likely picked up in the calving yard, as are subclinical (high cell count) cases in this time period.
Monitor the success of your dry period hygiene. On day four of lactation, California mastitis test (CMT) your cows before the milk is put into the bulk tank. This will help manage bulk milk cell counts and is a useful measure of dry period hygiene. No more than 10% of cows should be positive on CMT four days after calving.
Milk recording can provide further information on dry period hygiene, as well as dry cow therapy success. What percentage of cows which were dried off with a low cell count now have a high cell count? This is called your low-to-high rate and is a measure of dry period infection pressure.
To assess how well your dry cow therapy has worked you need to look at the percentage of cows, dried off with a high cell count and treated with antibiotics, now recording a low cell count. The target for this is >85%. However, the cows may have cured from the dry cow therapy but then picked up a new infection in the last two to three weeks of the dry period, even when teat sealant is used.
| Clinical mastitis cases in first 30 days of lactation
||< 1 in 12
| % cows high cell count at first recording in lactation
| % cows dried off with low cell count high at first recording (low to high)
| % cows high to low
If calves are born into an unhygienic environment, they can pick up infections through their mouth and navel. These pathogens may be present in the faeces of healthy cows and can cause significant illness in young animals.
There may also be a delay in clinical signs, so it may not be obvious the source of the infection was the calving yard. Once you have an infected calf in the calf housing the infection will rapidly spread between calves, so housing hygiene and isolation of sick calves is important.
Protozoa such as cryptosporidium can be particularly resistant, so it is important to use a cleaning product strong enough to kill them when disinfecting your calving shed. Steam cleaning can also be a great way to kill parasites.
It is also vital to ensure calves receive four litres of good quality colostrum within the first six hours of life. If you have a known disease problem on your farm you can boost the antibodies in colostrum by vaccinating cows before they calve against diseases such as rotavirus, E. coli, coronavirus and salmonella.
Extended colostrum or transition milk feeding can also help boost calf health in the first week of life by mopping up pathogens in the guts. However, this can transmit Johne’s disease to replacement heifers, so discuss with your vet first.
Due to the risk of calves picking up infections in the calving yard, it is advisable to remove the calves from calving pens as quickly as possible once they are born. They should be left no more than a day. Navels should be dipped as soon as possible after birth with iodine tincture to help them dry and kill bacteria.