The entire nine months of a beef cow’s pregnancy can be broken up into three stages; early, mid- and last trimester of gestation.
During these first two stages, her unborn calf doesn’t require a lot of nutrients, so it doesn’t put a lot of pressure on the cow. However, this all changes in the last 90 days of gestation, when 75 per cent of fetal growth occurs. The body condition of the cow and her mineral status both dictate how well her calf will perform at birth and in its lifetime. It is important to get the late-gestation cow ready for calving and it’s our job to especially build her up to adequate mineral status.
Beef producers have often asked me to develop late-trimester cow diets that favourably adjust the body condition of their pre-calving beef cow in just a few weeks. If they are too thin, I can increase the cow herd’s dietary plane of energy and protein nutrition with a few pounds of energy-enriched grain and/or protein supplement fed alongside their daily forage. I might also recommend they switch their cows onto better-quality hay and other forage. Yet when they ask me to help them build their herds to good calving mineral status, those requests can sometimes difficult to accomplish.
No quick fix
That’s because when a late-gestating beef cow is marginally or severely deficient in mineral status, it takes several months of feeding a well-fortified cattle mineral to build up and satisfy her respective NRC beef cow requirements. At the same time, we need to raise the mineral status of cow’s fetus, since it is totally reliant upon the cow’s intake of essential minerals digested and absorbed in her small intestine, transported in her blood and finally filtered through the placenta to her growing unborn calf.
For example, it is estimated that the late-gestation fetus (and placental tissues) takes slight precedence over the cow’s own mineral needs and can utilize up to 30 per cent of the pre-calving cow’s daily requirement for essential trace minerals. Once born, the newborn calf is dependent upon the Ig-enriched colostrum, which in itself, is rich in trace minerals and vitamins previously fed to the pregnant cow.
Whatever essential minerals and (vitamins) left over are then metabolized by the cow and used in the maintenance of her vital functions as well as support immune function. Some reproductive specialists also speculate that good cow fertility is linked, again to adequate mineral intake and metabolism. And it all needs to be established well in advance of her first active estrus after calving. University studies show that active follicle/egg development in the cow begins about 100 days before they are fully mature and released. It all happens when the female is pregnant with her current calf.
Several key elements
Four trace elements, in particular copper, zinc, manganese and selenium, form the cornerstones of most trace mineral programs for these late-gestation beef cows and newborn calves. Researchers have consistently found hay, greenfeed and other beef roughages grown across the Canadian Prairies are: (1) often low or marginally deficient in these four trace minerals and (2) in many cases, contain different antagonistic elements that bind the same essential trace minerals which makes them biologically unavailable to beef cows.
Over the years, I have formulated several pre-calving cattle minerals that not only contain high levels of these essential trace minerals, but I add them to mineral formulas in highly bioavailable chelated/organic forms along with forage-complementary levels of calcium, phosphorus and magnesium. Vitamins A, D and especially high levels of vitamin E are added too.
Once my well-balanced cattle mineral (with these macro minerals, trace minerals and vitamins) is provided to the cow herd and are consumed at three to four ounces per head daily, it is my intention that they reach the cows’ digestive tract, where they are: (i) quickly absorbed, (ii) efficiently metabolized and (iii) highly retained in the body to build good mineral status. As a result by providing a good cattle mineral-feeding program, it builds good mineral status in late-gestation cows (and her fetus), which ultimately means at calving time:
- More unassisted calvings with strong newborn calves.
- Fewer metabolic problems in fresh cows, such as fewer retained placentas and post-uterine infections.
- Good colostrum production and good transference of Ig-antibodies in newborn calves.
- Good immune function in mature cows and replacement heifers.
- Timely uterine involution, uterine repair and decrease number of days to active estrus.