Calving is when dairy cows are at greatest risk of disease. Many illnesses that arise around calving time not only cost in terms of time, money, stress and animal welfare but also impact negatively on fertility in the next mating period.
The major effect of cow health on reproduction arises through the development of endometritis (‘dirty' cows). Endometritis is an infection of the lining of the uterus. The cow is not visibly unwell and there may or may not be a pussy (white to yellowish) discharge from her vulva. Cows that have endometritis will usually still cycle normally but have reduced conception rates as their uterus provides an unhealthy environment for an embryo to implant.
New Zealand studies have shown that cows with endometritis conceive 2-3 weeks later than normal cows and have 10-30% higher empty rates. Cows with endometritis are also at a much higher risk of developing pyometra (uterus full of puss).
Appropriate diagnosis and treatment can result in very significant cost benefits through:
- Extra days in milk
- Fewer empties
- More AB calves to select from
- Less wasted semen
- Fewer inductions
The following diseases put cows at a higher risk of endometritis. These cows are known as ‘at-risk' cows:
- Retained foetal membranes (RFMs) - membranes still in 24 hours after calving
- Difficult calving - assisted or natural
- Twins
- Dead calf - born dead or dies within 12 hours of birth
- Inductions
- Uterine prolapse
- Ketosis/fatty liver disease
- Downer cows
- Vaginal discharge
Although ‘at-risk' cows are at a higher risk of being dirty, 10-15% of cows that had no problems at calving will also develop endometritis. Totally Vets can detect the majority of these using a metricheck tool which allows a quick, on-the-spot diagnosis of endometritis.
What options do you have this season for limiting the impact of endometritis on your herd's fertility?
One option is to record all ‘at-risk' cows and any other cows with a discharge and have these examined by Totally Vets in batches 3-4 weeks after calving. Anything with clinical endometritis can be treated with a nil withholding intra-uterine antibiotic at this time. There is evidence that also treating ‘at-risk' cows that have no discharge will improve their pregnancy rates as many of these cows have sub-clinical infections. If a lot of your ‘at-risk' cows are from RFMs then this may be a viable option.
A second option is to have the whole herd metrichecked 5-6 weeks prior to the start of mating. Any cows that have not been calved 2 weeks at this point should be re-examined at a later date.
A certain number of cows will develop endometritis in any herd regardless of how well they are managed. Things you can do to reduce the number of 'at-risk' cows include ensuring cows are in optimal calving condition and are well-transitioned; supplementing with trace elements as needed; being very hygienic when assisting in calvings and treating any illnesses/conditions that arise around calving time promptly and appropriately. Induced cows have a significantly higher risk of RFMs and hence endometritis. Focus on tightening up your calving spread and pull the bull out earlier so that you do not need to induce.
The following are acceptable levels of illness in a herd; if your herd is above any of these levels then you should seek help.
| Retained foetal membranes | 2% |
| Stillborn calves (or die within first 24 hours) | 1% |
| Assisted calvings | 5% |
| Other health problems (e.g. ketosis, milk fever etc.) | 5% |
Contact Totally Vets to make a plan for reducing the impact of endometritis in your herd.
