Increasing reproductive performance
Every year we are asked “How can I increase the reproductive performance of my herd?”
We start by saying that every cow should be metrichecked and any infected cows treated - this has already been covered last month.
The next important thing to do is pre-mating heat recording from about one month before planned start of mating. Pre-mating heat detection is an opportunity to practise heat detection skills and gain insight into which cows should be cycling once mating starts. It is also the easiest way to identify non-cycling cows and gain insight on whether intervention is required.
Use tail paint to identify cycling cows – one colour tail paint to start, then a second colour to re-paint as they cycle and need to be re-painted. Within two weeks about half the cycling cows should have been identified. At three weeks, cows with the original colour are the non-cyclers or cows that have had very weak cycles.
A period of non-cycling called “anoestrus”, following calving is normal and cows will start coming on heat as the uterus recovers from pregnancy and reduces in size. Typically, cows will first ovulate six weeks after calving.
Non-cycling cows at the start of mating, also known as No Visible Oestrus (NVO) or anoestrous cows, are a common problem on most dairy farms in New Zealand. These ‘non-cyclers’ reduce the reproductive performance of the herd and consequently reduce the financial performance of the farm, as cows take longer to become pregnant and hence produce less milk.
There are two types of non-cyclers
- Cows that have ovulated (i.e. ovaries are ‘cycling’) but cows have not displayed a detected heat (silent oestrus or ‘missed heat’)
- Cows that are yet to ovulate
Conditions that prevent cows coming into oestrus post-calving include
- Inadequate nutrition pre- and post-calving, including metabolic issues/ketosis (clinical or subclinical)
- Any chronic debilitating disease, such as uterine infection (metritis), mastitis, lameness, left displaced abomasum, or other cause of significant weight loss
First calving heifers usually take longer to show cycling activity due to the nutritional stresses resulting from continued growth and lactation, and often make up a higher proportion of non-cycling cows.
Treating anoestrous cows prior to the start of mating with a CIDR programme provides the best economic return as treated cows have an average of 21 more days in milk the next season. The CIDR programme takes 10 days to complete from CIDR insertion to insemination. This is the best time to use CIDRs as it helps to bring the later calvers in line with the rest of the herd.
If you have any queries about this subject or would like to discuss the CIDR programme do not hesitate to give your local veterinarian a call.