CYSTIC OVARIES IN POST PARTURITION DAIRY COWS
I have read several articles about the cause of cystic ovaries in post parturition dairy cows an as an nutritionist I would like to ask the following questions:
1) Is there a correlation between body condition scores and the incidence of cystic ovaries when cows are being fed a balance ration
2) Are cows with a body condition score of 2-2.5 after calving predisposed to cystic ovaries.
3) It appears cystic ovaries are more closely related to hormonal imbalances than nutritional factors. Is this correct??
Many thanks as I look forward to your responses.
Outside United States
Cystic ovaries seem to be one of those problems where there is a lot of finger pointing, but no, or inconsistent, data to support the claim. There is an article in Hoard's Dairyman from 2012 (http://www.hoards.com/12jan10-cystic-ovaries) that gives a pretty good synopsis of the problem. It is obvious that we still don't have all of the answers.
In answer to your direct question, as long as the ration is properly balanced and is fed to match the needs of the cow, there is no evidence to suggest the ration is the cause to this problem. However, as mentioned in the Hoard's article, some specific feeds that have phytoestrogens or other compounds that have hormonal properties may contribute to the problem.
In terms of body condition score and cystic ovaries, there is at least one research article that suggests that prepartum cow that are over-conditioned, lose more body score postpartum than other cows. This lower body condition score was associated with higher cystic ovaries due to changes in IGF-I. If this change in IGF-I is a contributing factor then it is consistent with the idea that hormonal imbalances play a role, but the exact cause is still a matter of debate. Others have not found an association to BCS and cystic ovaries. Several years ago researchers from the University of Wisconsin found that as milk production increased, blood flow through the liver also increased. They found that this increased the metabolism of estrogens and progesterone and lowered blood levels of these hormones. This may also be an associated factor.
In summary, nutritional factors are not generally considered to the prime factor in cystic ovarian disease, but a balanced ration is important to make sure it isn't playing a minor role.
Many thanks for your reply...especially over the Easter weekend. I was only expecting your response next week.
I do hope you are having a special weekend.