Effects of feeding a vitamin and mineral supplement to cow-calf pairs grazing native range
(AS2040-4, September 2021)The objectives of this study were to evaluate the influence of feeding a vitamin and mineral (VTM) supplement to pregnant cows and suckling calves during the summer grazing period on native rangeland. Although performance measures in cows or calves were not affected, concentrations of liver mineral were enhanced in cows and calves that had access to free-choice mineral while grazing summer pastures.
This article is part of the 2021 North Dakota Livestock Research Report.
Friederike Baumgaertnert, Timothy Long, Cody Wieland, Kevin Sedivec and Carl Dahlen
Summary
Our objectives were to evaluate how providing free-choice vitamin and mineral (VTM) supplements to cow-calf pairs during the summer grazing period on native range affects cow and calf performance and liver mineral concentrations. During a two-year period, Angusbased crossbred cow-calf pairs (n = 727; n = 381 in year 1, n = 346 in year 2) from the Central Grasslands Research Extension Center (Streeter, N.D.) were assigned to pastures (16 in year 1, 14 in year 2), which then were assigned to receive a free-choice mineral supplement (Mineral) or no mineral supplement (NoMineral). Prior to treatment assignments, all cow-calf pairs received a common diet as a total mixed ration including a mineral supplement for 120 days before pasture turnout. The grazing periods for year 1 and year 2 were 158 and 156 days, respectively, and treatments began at pasture turnout and concluded at pasture removal. Cows were bred on pasture using artificial insemination followed by natural service cleanup bulls for a 70- to 80-day breeding season. Weights were collected from cows and calves at pasture turnout and removal and liver biopsies were taken from a subset of cows and calves. Additionally, birth weights and calving distribution were evaluated. Cow and calf weights and weight change during the grazing period were not impacted (P ≥ 0.47) by access to VTM supplement. Furthermore, the pregnancy rate and subsequent birth weight and calving distribution were not affected (P ≥ 0.36) by treatment. Liver concentrations of selenium, copper and cobalt were greater (P ≤ 0.002) at pasture removal and weaning for cows and suckling calves that had access to VTM. Although VTM supplementation enhanced concentrations of key minerals in the liver of cows and calves, performance was not impacted.
Introduction
Successful cow-calf herds rely on reproductive efficiency to maintain profitability; thus, maintaining adequate maternal nutritional status, including vitamin and mineral nutrition, is essential to optimal growth, development and programming of the fetus (Kegley et al., 2016). However, management strategies vary widely across beef herds, with innumerable strategies of offering vitamin and mineral supplementation and intensities of supplementation programs being implemented by producers.
Vitamins and minerals are transferred across the placenta to the growing fetus during gestation; however, the long-term implications of the mineral status established at birth in the neonate have yet to be elucidated (Hidiroglou, 1980; Hostetler et al., 2003; Menezes et al., 2021). Therefore, this study evaluated influences of vitamin and mineral supplementation on growth performance and mineral status of the dam and suckling calves throughout the grazing period, reproductive success in the dam, and birthweight and calving distribution of the calf crop.
Experimental Procedures
Animals, Housing and Diet
During a two-year period, 727 Angus-based crossbred cow-calf pairs (n = 381 in year 1, n = 346 in year 2) were used at the Central Grasslands Research Extension Center to evaluate the influence of providing free-choice VTM supplements during the grazing season on cow-calf herd performance. Prior to treatment assignments, all cows and calves were fed a common diet as a total mixed ration including a mineral supplement for 120 days before pasture turnout.
Cow-calf pairs were blocked by cow age, then randomly assigned to one of 16 pastures in year 1 and one of 14 pastures in year 2. Pastures were assigned randomly to one of two treatments: 1) free choice VTM supplement was available in the pasture (Mineral) or 2) no mineral supplement was available in the pasture (NoMineral). The grazing period for years 1 and 2 were 158 and 156 days, respectively, and treatments began at pasture turnout and concluded at the time the pairs were removed from pasture.
All pastures were stocked at the same stocking rate to achieve 40% to 50% degree of disappearance. The vitamin and mineral supplement was offered in free-choice mineral feeders placed in each pasture and consumption was monitored. Mineral feeders were accessible for all cows and calves on pastures receiving the treatment.
The vitamin and mineral supplement in year 1 was Stockmen’s Supply Repromune MIN YC (Stockmen’s Nutrition, West Fargo, N.D.) and in year 2, the supplement offered was Payback Research 12-6+ (CHS Nutrition, Sioux Falls, S.D.). Cows were synchronized using a 7-CoSynch artificial insemination (AI) protocol and bred to multiple sires and natural service cleanup bulls were turned out shortly after AI.
Pregnancy status was determined via transrectal ultrasonography at least 40 days after bull removal to determine overall pregnancy rates. Cows remained on pasture with their suckling calf until the end of the grazing season (weaning).
Mineral Status
Liver biopsies were taken at pasture turnout and removal from a subset of 16 cows in year 1 and 42 cows in year 2. In addition, samples were collected from a subset of 47 calves in year 1 and 35 calves in year 2 within a week of weaning.
Samples were collected using a Tru-Cut biopsy trochar (14 g; Becton Dickinson Co., Franklin Lakes, N.J.) using techniques outlined by Engle and Spears (2000) and McCarthy et al., (2019). Samples were analyzed for concentrations of selenium, iron, copper, zinc, molybdenum, manganese and cobalt at the Diagnostic Center for Population and Animal Health at Michigan State University using inductively coupled plasma mass spectrometry.
Statistical Analysis
Mean values for individual cows and calves within a pasture were calculated and used to represent the pasture in the final data set. For concentrations of liver mineral, mean pasture values were calculated for each pasture and used for analysis. Data were analyzed for the effect of VTM treatment (Mineral or NoMineral) using the GLM procedure of SAS with pasture as the experimental unit. Differences were considered significant at a P-value ≤ 0.05.
Results and Discussion
Cow weight change and pregnancy attainment were not influenced by VTM supplementation on pasture (P = 0.99 and P = 0.36, respectively; Table 1). Pregnancy rates in suckled beef cows between both years were not different between treatments, with mineral supplemented cows at 95.3% and nonsupplemented cows at 96.4% (P = 0.36; Table 1). Overall performance and pregnancy success were adequate for cows in both treatment groups.
| Item | No Mineral1 | Mineral1 | SE | P-Value |
|---|---|---|---|---|
| Turnout wt, lbs. | 1,325.0 | 1,330.5 | 30.6 | 0.90 |
| Pasture removal wt, lbs. | 1,384.5 | 1,390.3 | 30.4 | 0.89 |
| Cow wt change, lbs. | 58.0 | 58.0 | 7.41 | 0.99 |
| Pregnancy rate, lbs. | 96.4 | 95.3 | 0.82 | 0.36 |
1 - Treatments: No Mineral–Cows were grazing pastures with no access to a mineral supplement or Mineral–Cows were grazing pastures with access to a mineral supplement.
Weaning weights of suckling calves were also not different (P = 0.47) between treatments, with Mineral calves weaned at an average of 605 pounds and No Mineral calves weaned at an average of 595 pounds (Table 2). Additionally, average daily gain (ADG) was not different between treatments (P = 0.325).
| Item | No Mineral1 | Mineral1 | SE | P-Value |
|---|---|---|---|---|
| Suckling calf | ||||
| Turnout wt, lbs. | 185.4 | 183.0 | 2.92 | 0.56 |
| Weaning wt, lbs. | 595.0 | 604.8 | 9.55 | 0.47 |
| Calf gain, lbs.2. | 410.3 | 421.9 | 8.14 | 0.32 |
| Calf ADG, lbs. | 2.61 | 2.69 | 0.05 | 0.32 |
| Gestating calf | ||||
| Day of calving | 17.75 | 18.22 | 0.92 | 0.72 |
| Birth wt, lbs. | 85.26 | 86.62 | 1.25 | 0.45 |
1 - Treatments were: No Mineral–calves were grazing pastures where they (along with their dams) had no access to a mineral supplement or Mineral–calves were grazing pastures where they (along with their dams) had access to a mineral supplement.
The birth weight of the calf conceived during the grazing season did not differ (P = 0.447; Table 2) between treatments, with Mineral calves averaging 87 pounds and NoMineral calves averaging 85 pounds at birth. The date of birth in the calving season was also not impacted by treatment (P = 0.72).
The in-utero environment experienced by calves during gestation is a product of the dam’s environment. Nutrients consumed, climactic conditions and stress experienced by dams all can impact the developing fetus.
Vitamins and minerals can serve several key roles in growth and development in the body of the gestating dam as well as the fetus, including structural, physiological, catalytic and regulatory functions, which contribute to effects on hormone production, enzyme activity, tissue growth, oxygen transport and energy production (Menezes et al., 2021). Evaluation of calf crops conceived by dams that received different VTM treatments during the grazing period (the first trimester of gestation) should be continued at later post-natal and post-pubertal time points.
Liver selenium, copper and cobalt concentrations were greater (P ≤ 0.002) in Mineral cows at pasture removal compared with NoMineral cows (Table 3). Additionally, the change in concentrations of liver selenium, copper and cobalt from pasture turnout to pasture removal was greater (P ≤ 0.003) for Mineral cows than NoMineral cows. At pasture removal, concentrations of iron, zinc, molybdenum and manganese in cows were not influenced (P ≥ 0.222) by treatment.
| Sample | No Mineral2 | Mineral2 | SE | P-Value |
|---|---|---|---|---|
| Se Turnout | 1.87 µg/g | 1.78 µg/g | 0.066 | 0.33 |
| Se Removal | 2.22 µg/g | 2.87 µg/g | 0.138 | 0.002 |
| Se CHG3 | 0.34 µg/g | 1.08 µg/g | 0.155 | 0.002 |
| Fe Turnout | 276.1 µg/g | 263.0 µg/g | 18.46 | 0.61 |
| Fe Removal | 265.1 µg/g | 252.0 µg/g | 15.73 | 0.55 |
| Fe CHG | -11.05 µg/g | -11.03 µg/g | 16.40 | 0.99 |
| Cu Turnout | 204.8 µg/g | 183.1 µg/g | 12.97 | 0.23 |
| Cu Removal | 183.0 µg/g | 302.4 µg/g | 19.89 | <0.001 |
| Cu CHG | -21.84 µg/g | 119.28 µg/g | 20.40 | <0.001 |
| Zn Turnout | 139.8 µg/g | 141.1 µg/g | 8.66 | 0.91 |
| Zn Removal | 149.0 µg/g | 172.2 µg/g | 13.5 | 0.22 |
| Zn CHG | 9.29 µg/g | 31.09 µg/g | 14.49 | 0.28 |
| Mo Turnout | 3.78 µg/g | 3.82 µg/g | 0.121 | 0.82 |
| Mo Removal | 4.30 µg/g | 4.20 µg/g | 0.092 | 0.46 |
| Mo CHG | 0.514 µg/g | 0.381 µg/g | 0.127 | 0.45 |
| Mn Turnout | 11.13 µg/g | 11.44 µg/g | 0.326 | 0.52 |
| Mn Removal | 11.16 µg/g | 11.44 µg/g | 0.316 | 0.52 |
| Mn CHG | 0.035 µg/g | 0.003 µg/g | 0.344 | 0.95 |
| Co Turnout | 0.239 µg/g | 0.233 µg/g | 0.0109 | 0.70 |
| Co Removal | 0.163 µg/g | 0.300 µg/g | 0.0278 | 0.001 |
| Co CHG | -0.076 µg/g | 0.067 µg/g | 0.0319 | 0.003 |
Se = Selenium, Fe = Iron, Cu = Copper, Zn = Zinc, Mo = Molybdenum, Mn = Manganese, Co = Cobalt
1 - For this analysis, mineral concentration values were averaged between years 1 and 2.
2 - Treatments were: No Mineral–Cows were grazing pastures with no access to a mineral supplement or Mineral–Cows were grazing pastures with access to a mineral supplement.
3 - Change in concentration: reflects the concentration at pasture removal minus the value from pasture turnout.
At weaning, concentrations of selenium, copper and cobalt were greater (P ≤ 0.001) for calves managed on Mineral pastures compared with calves managed on NoMineral pastures (Table 4). Concentrations of iron, zinc, molybdenum and manganese in calves were not influenced (P ≥ 0.17) by treatment at weaning.
| Item, µg/g | No Mineral1 | Mineral1 | SE | P-Value |
|---|---|---|---|---|
| Se | 1.62 | 1.93 | 0.063 | 0.001 |
| Fe | 203.8 | 179.3 | 14.93 | 0.25 |
| Cu | 48.4 | 103.3 | 6.88 | <0.001 |
| Zn | 168.3 | 169.0 | 6.50 | 0.94 |
| Mo | 3.45 | 3.19 | 0.130 | 0.17 |
| Mn | 8.78 | 9.06 | 0.277 | 0.47 |
| Co | 0.114 | 0.172 | 0.009 | <0.001 |
1 - Treatments were: No Mineral–Calves were grazing pastures with no access to mineral supplement or Mineral–Calves were grazing pastures with access to mineral supplement. Payback Research 12-6+, CHS Nutrition, Sioux Falls, S.D. Values from 35 calves used to determine pasture averages.
In the current experiment, providing a mineral supplement to suckled cows did not influence performance of the cows, suckling calves or gestating calves (Tables 1 and 2). However, data provided in Tables 3 and 4 indicate that liver mineral concentrations were enhanced in cows and calves provided with a mineral supplement during the grazing period.
Research by Ahola et al. (2004) supported similar findings, with greater copper liver mineral concentrations in supplemented dams compared with nonsupplemented dams for two years, but performance data varied slightly as a result of mineral supplementation. In the study by Aloha et al. (2004), overall 60-day pregnancy rates tended to be higher for supplemented cows compared with nonsupplemented cows, an effect that was not observed in the current study. Management factors that impact pregnancy attainment or calf growth warrant careful investigation because of their intricate relationship with herd profitability.
Weaning data for calves conceived and gestated in year 2 of this experiment will be collected in the fall of 2021, which will complete a dataset used to evaluate the impact of early gestation mineral supplementation on subsequent offspring performance. When evaluating overall implications of pasture-based mineral supplementation programs, additional evaluations, including assessing immune status of the suckling calves, and post-weaning health implications should be considered. Strategies that enhance immunity and reduce susceptibility to disease in newly weaned calves would be a great benefit to backgrounding and feedlot operations.
The effects on the gestating calf receiving the mineral treatment in utero also should be evaluated further in terms of the potential to program the growing fetus to utilize micronutrients more efficiently. Furthermore, vitamin and mineral deficiencies during stressful events in a calf’s life, such as weaning and transport, can become more apparent (Kegley et al., 2016). Decreasing the incidence of morbidity and maintaining calf health may be an outlet to increasing overall calf performance, but further research is necessary to determine the impact vitamin and mineral supplementation may have in scenarios where calf immune status is challenged.
Literature Cited
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Engle, T.E., and Spears, J.W. (2000). Effects of dietary copper concentration and source on performance and copper status of growing and finishing steers 1. J. Anim. Sci, 78, 2446– 2451. https://academic.oup.com/ jas/article/78/9/2446/4670853
Hidiroglou, M. 1980. Trace elements in the fetal and neonate ruminant: a review. Can. Vet. J. 21:328-335.
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Kegley, E., J. Ball and P. Beck. 2016. Bill E. Kunkle Interdisciplinary Beef Symposium: Impact of mineral and vitamin status on beef cattle immune function and health. J. Anim. Sci. 94:5401-5413. doi:10.2527/jas2016- 0720
McCarthy, K.L., Underdahl, S.R., Undi, M., Becker, S., and Dahlen, C.R. (2019). Utilizing an electronic feeder to measure mineral and energy supplement intake in beef heifers grazing native range. Translational Animal Science, 3, 1719–1723. https://doi. org/10.1093/tas/txz065
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