There is a lot of reproductive pressure upon a beef cow after calving.
She has only about 80 to 85 days to overcome general and uterine postpartum infections, make repairs to her reproductive tract and finally return to a normal estrus cycle. Failure to rise above any one of these challenges may lead to a breakdown in her profitability by extending the breeding/calving season, producing a poor calf, or even becoming pregnant. Producers don’t have much of a choice, but to cull these infertile cows.
No worries! Beef cows can easily return to an active reproductive life, if they are provided with a comprehensive feeding program during critical pre-and post-calving periods. Part of this dietary package encompasses a well-balanced beef mineral that tends to maintain or improve good cow mineral status. Many producers whom have made substantial upgrades to their trace mineral beef cow programs frequently observe respective improvements to the general health and reproductive life of their cows.
FOUR KEY MINERALS
Within any sound postpartum beef cow mineral program, there are four particular trace minerals, which are very important for good beef cow reproduction. Often enough, they are either low or marginally deficient in soils/cattle forages or are bound up by antagonistic elements that make them “biologically unavailable” to even the most fertile beef cow. The specific four trace minerals that are important for good beef cow reproduction are: copper, zinc, manganese and selenium.
Signs of a hidden or subclinical trace mineral deficiency of one of these four trace minerals in a breeding beef herd tend to be invisible, could be similar to other mineral deficiencies or, even be entirely due to some other feed or non-feed problem. Yet, there is a common thread that links together many reproductive problems among infertile beef cows that do not consume, absorb or metabolize enough of these four trace elements to meet their basic trace mineral requirements.
General reproductive problems observed in beef cows with poor mineral status of each of these four trace minerals by beef producers and backed by many years of university and industrial research are:
Copper — Reduction in first-service conception rates, poor embryonic survival. Deficient cows may actually show normal estrus behaviour, but normal ovulation does not occur and may lead to future estrus retardation. Erratic estrus cycles might be caused by antagonistic minerals such as molybdenum or high levels of zinc affecting copper metabolism.
Manganese — Delayed estrus, “silent heats,” poor fertilization in postpartum cows. Abortions and deformed fetuses are common in manganese-deficient cows. Research has demonstrated that the manganese content in healthy ovaries of fertile cows is significantly higher than cows with abnormal cystic ovaries.
Zinc — Although zinc is involved in the activation of over 300 enzyme systems that drive chemical reactions in the body, there is only moderate evidence that zinc plays a direct role in female beef reproduction compared to copper, manganese and selenium. Rather, delay in estrus or failure to conceive due to a marginal or severe zinc deficiency is caused by a problem associated with zinc’s energy and protein metabolism involvement.
Selenium (and Vitamin E)— A lack of dietary selenium is often associated with retained placentas and an increased incidence of metritis (uterine infection). More selenium-deficient symptoms in beef cows include: an increased frequency of silent heat cycles, more cystic ovaries as well as early embryonic deaths.
One should keep in mind that the above reproductive symptoms due to a dietary deficiency of copper, manganese, zinc and selenium are only a tip of the nutritional “iceberg” in the complete functions of these essential elements. All of these four trace minerals are interactive and interdependent with one another as activators in major cellular enzyme systems. For instance, all four elements play a role in the super dismutase enzyme system, which is involved in immune function (a. k.a. general health) of the fertile beef cow. Without them, the beef cow would be largely unable to fight infection or disease.
Fertile beef cows may achieve adequate trace mineral status of copper, manganese, zinc and selenium by consuming respective biologically available amounts based on recommendations outlined by the National Research Council (NRC).
The actual amount of each of these trace minerals added to a good post-calving diet or in commercial beef mineral and fed for the next 80 to 85 days after calving until the start of the breeding season will vary. Mitigating factors range from: age and body condition of the cow herd, their general health condition after calving, any particular or specific forage mineral nutrient profiles to the type of mineral sources that are used (re: inorganic or organic) in this diet or commercial mineral.
Buying the right commercial “breeder” mineral is a matter of finding one that meets all the cows’ essential macro-and trace-minerals as well as vitamins A, D, and E requirements. Such nutrient needs not only play a critical role in maintaining basic body functions of the whole cow herd, but supports high milk production for their calves, keeps up a healthy immune system and promotes several reproductive activities, so the cows can get pregnant with next year’s calf.
Regardless of what type of mineral that anyone’s cattle actually needs until the breeding season, it still is quite common for many people that are buying cattle mineral to prematurely ask, “How much is this mineral going to cost me?” Cow-calf producers should avoid shopping for cattle mineral simply based on the beef mineral’s price. Although, it’s a hard reminder for everyone (including those people who purchase the best of the best cattle mineral, no matter what it costs), the best recommendation for shopping for cattle mineral is to look for nutritional value — which means; choose a reasonable-priced mineral that matches your cows’ breeding mineral needs.
PeterVittiisanindependentlivestock nutritionistandconsultantbasedinWinnipeg. Toreachhimcall204-254-7497orbyemailat [email protected]
Mineral Requirement of Postpartum Beef Cows
Selenium 10 ppm (maximum, 100 ppm)
40 ppm (max, 1,000 ppm)
50 ppm (max, 500 ppm)