Each year, as calving season approaches, there is a palpable anticipation. Even the initial midnight checks are enjoyable as new calves are born and tagged. The entire focus seems to be on making sure calves get up, consume colostrum and receive any other forms of TLC that are deemed necessary to give that calf the best chance of survival possible. While attention is rightfully paid to the calf, the new mom can be easily forgotten. Even more concerning is that the clock for successfully having another calf born next year begins ticking before this calf is even licked clean.
More than body condition
Reproductive success on a cow-calf operation is the lifeblood of economic stability. Biologically speaking, reproduction is a bit of a luxury. Nutrients must be present to sustain the life of the new baby and mom, including repairing the uterus from the previous pregnancy, before the body will partition nutrients to generate a new pregnancy. Body condition scores (BCS) have been well documented as an indicator of reproductive success. Cows that lose excessive body condition following calving may not have adequate energy reserves to resume the ovarian cyclicity needed to be ready to breed at the beginning of the breeding season. Trace minerals are also essential nutrients needed for reproductive efficiency, but identifying deficiencies is much more difficult than a visual evaluation. Trace minerals play important roles in hormonal regulation, uterine health and embryonic viability. Without trace minerals, cows may not be ready to breed back as quickly as needed.
Why the drop?
If cows are on a balanced trace mineral program, why should there be concern about the cow’s mineral status? The answer is not that minerals are lacking but that we need to account for where the minerals go and the time required to recover. Trace minerals have four basic functions: physiologic (reproductive, immunologic and neurologic functions), catalytic (enzymes and hormones), regulatory (apoptosis – programmed cell death) and structural (skin, bones and tendons). During pregnancy, the dam must provide these trace minerals for fetal development. Toward the end of gestation, the calf must also store adequate levels of trace minerals in its own liver to survive for the first few months after being born. These reserves are necessary because the milk that will be the primary source of nutrients for the calf has inadequate levels of trace minerals to support ongoing growth and development.
Cows with inadequate trace mineral status in the third trimester have been shown to increase rates of stillborn calves by up to 30 times and have calves 13 times more likely to have scours compared to cows with adequate trace minerals. The large quantities of trace minerals taken by the developing fetus result in an approximate 30% drop in trace mineral levels in the cow at calving. University studies have shown that feeding 150% of the National Academies of Sciences, Engineering and Medicine (NASEM) required levels of trace minerals may still take anywhere from 28 to 42 days to recover, depending on the inclusion rate of organic minerals, which have better absorption rates. If cows are not successful in replenishing depleted trace mineral levels, cows may not begin cycling in time for breeding season, or worse, they may not be able to maintain the pregnancy after conceiving.
The best shot for reproductive success
Injectable trace minerals provide a mechanism to rapidly increase the trace mineral status of the cow so that adequate levels are available for reproduction. This is due to the route of administration, which avoids the typical hurdles encountered by oral trace mineral supplementation. Rumen antagonists and low absorption rates prevent oral minerals, including drenches and pastes, from being able to increase mineral levels in the cow in an efficient manner. By being absorbed directly into the bloodstream and bypassing the digestive tract, trace mineral levels can be increased in the blood within eight to 10 hours before seeing significant increases in the liver within 24 hours. Utilizing injectable minerals prior to bull turnout can help restore the trace mineral status of the cow and improve the likelihood of cows returning to estrus in time for breeding season. Maintaining these improved levels with an oral supplement can then assure that cows have the necessary minerals for successful breedback and pregnancy maintenance, hallmarks of reproductive success.
Don’t forget the bull
Outside of the breeding season, bulls are largely thought of as a necessary evil on the ranch. Despite often being the most expensive bovid on the place, they are asked to work for just a few months out of the year, with the hope that they don’t destroy the facilities during their time off. When it comes to fertility, trace minerals are important in the production of fertile semen. With an approximate 63-day production process for spermatozoa, inadequate trace minerals can have devastating effects on next year’s calf crop. Trace minerals are found in high concentrations in the semen to protect the sperm cells from the harsh vaginal environment. Incorporating an injectable trace mineral protocol during breeding soundness exam time can help to improve the quality of the sperm that will be used to impregnate females in the upcoming breeding season.
In order to maintain a 12-month calving window, a cow only has 80 days to recover from giving birth until conception. In addition to adequate energy and protein, essential micronutrients such as trace minerals impact the success of the breeding season for both cows and bulls. By making sure the cows’ needs are met, we can anticipate another exciting calving season next year.
