After attending this year’s Joint Annual Meeting for the American Dairy Science Association, American Society of Animal Science and Canadian Society of Animal Science in Kansas City, I asked all of our Miner staff who attended to share something they learned at our weekly research staff meeting. For me, I learned that a 50+-year-old mother of three should probably never ride a mechanical bull or pig…lesson learned.
Actually, I attended an interesting symposium discussing Reproductive Success in Ruminants: A Complex Interaction Between Endocrine, Metabolic and Environmental Factors. It was not only refreshing to be able to listen to a discussion that didn’t involve fiber (no offense to you pef junkies), but the title itself was encouraging…Reproductive Success in Ruminants. Cool.
In 2010, I wrote a Farm Report article that asked the question, Does High Milk Production Decrease Fertility? I’ve always believed that high production and decreased fertility don’t go hand-in-hand…with some of the highest producing herds having the highest conception rates. But what sets some herds apart from others? Is it nutrition? Is it management?
Dr. Iain Clarke from Monash University in Australia, helped provide some pieces to the puzzle when he reviewed recent advances in our understanding of the hypothalamic control of reproduction. As with all of the body’s functions, the brain, specifically the hypothalamus and pituitary, drives the reproductive process. Dr. Clarke discussed a couple of hormones I didn’t know much about: kisspeptin (KP) and gonadotropic inhibitory hormone (GnIH). KP may function to integrate energy balance, metabolism, and the endocrinology of reproduction.
While KP is viewed as a stimulator of gonadotropic releasing hormone (GnRH – the hormone responsible for release of follicle stimulating hormone and luteinizing hormone from the pituitary gland), GnIH has the opposite effect. Some recent work with sheep have found that GnIH inhibits reproductive behavior expression and is regulated by melatonin and stress. We’ve always had a hunch that reproduction can be impaired by stress (heat stress, overcrowding, etc.) but now we have a possible mechanism for how reproductive behavior and physiology are being influenced by stress-related hormones.
Without getting any deeper into reproductive endocrinology, (sigh of relief from the Farm Report readership) the bottom line is that the underpinning to reproductive success is nutrition and cow comfort. Fortunately for us at Miner Institute, that is the type of research we do best. While more work in this area needs to be done, any improvements in cow comfort on your farm are not only going to improve animal productivity but also her reproductive performance as well.