- Animals: bovine
- Animal Production: animal protection and health, livestock breeding
The purpose of this project was to evaluate the effects of an injectable trace mineral supplement administered prior to breeding on reproductive parameters including pregnancy rates, calving distribution, and calf weaning weights. A total of 5 commercial beef cattle operators were selected by their local North Dakota State University county extension agents to participate in this research effort. Prior to involvement, telephone conversations were had with each producer to explain project details, detail producer involvement, and answer any questions. Within herd at each location, cows were stratified by days postpartum, then randomly assigned to receive one of two treatments: 1) Cows received no additional treatments prior to bull turnout (CON; n = 755) or 2) Cows were administered an injectable trace mineral supplement (60, 10 and 15 milligrams per milliliter (mg/mL) of zinc, manganese and copper as disodium EDTA chelates, and 5 mg/mL of selenium as sodium selenite) subcutaneously 30 d before bull turnout (TM; n = 764). On the day of mineral administration, blood samples were collected from a random sample of females (n = 46; 8 to 10 females per herd) immediately prior to mineral injection via jugular venipuncture and were analyzed for baseline mineral status. Total mixed rations were collected for the animals still in confinement prior to pasture/bull turnout and water samples were collected from all available water sources for each herd.
Cooperating producers beginning the project in Year 1 (2015) included Thorne Ranch, Watford City, ND, Hoff Ranch, Dickenson, ND, Schultz Ranch, Sheldon, ND, Ruland Ranch, New Town, ND. Year 2 (2016) included Roise Ranch, Powers Lake, ND.
Preliminary results from Year 1 were completed by late 2016/early 2017, whereas results from Year 2 were collected by late 2017/early 2018. Results indicated that there was no difference (P = 0.29) in the pregnancy rates of females between groups (TM: 91.1% and CON: 93.2%). Weaning weights of calves on the side of cows receiving treatments also were similar (P = 0.90), and mean calving date was not different (P = 0.99) for those calves born from ITM cows or CON cows. When evaluating the distribution of calves born in the calving season by 21-d increments, the proportion of calves born in the first 21, 22 to 42, or more than 42 d of the calving season were similar (P = 0.40) between groups.
Blood, feed, and water samples were collected. No differences (P = 0.11) were observed in the blood mineral levels between treatments for cobalt, copper, iron, manganese, molybdenum, selenium, or zinc before treatment administration.
Reproductive performance and superior overall herd health are vital to a successful and profitable cow herd. Deficiencies of trace minerals can lead to anemia, immune suppression, reduced ovulation, irregular estrous cycles, fetal malformations, and abortions, as trace minerals are vital to fetal development and nutrient transfer (Hostetler et al., 2003). Increased reproductive failure and herd death loss could result in decreased profitability for cattle producers.
The foundation of grazing beef cattle diets consists of roughly 85% forage, however not all nutrients can be obtained from forage alone (Greene, 2000). The National Research Council (NRC) has established requirements for successful animal production, based on ongoing research, for most minerals thought to be essential in beef cattle diets. If not found in feedstuffs, minerals should be supplemented to influence immunity, reproduction, and weight gain (Lalman and McMurphy, 2004). Mineral composition of forages, types of supplementation and individual animal intake of mineral supplementation are highly variable. Additionally, palatability, individual requirements, mineral content of available water sources, and season of year are all factors that must be considered when evaluating the consumption of mineral supplements as each is a factor affecting intake of minerals (McDowell, 1996).
Injectable trace mineral products are currently available and may be used for a more targeted supplement delivery. Injectable mineral products are, however, not blanket nutrients or broad spectrum, but contain only a few trace minerals: copper, manganese, selenium, and zinc. The label of injectable trace mineral products explicitly states that they are NOT a mineral replacement product and that other sources of mineral should be available to cattle. Injectable mineral supplements currently available are labeled as a source of zinc, manganese, selenium, and copper to be administered four weeks before calving and four weeks before breeding in beef cows (Multimin 90, USA). Particular minerals involved in reproductive performance and growth include but are not limited to copper, manganese, selenium and zinc (Hostetler et al., 2003). Copper is required for red blood cell formation and regulation, manganese for fetal bone formation, and selenium and zinc are required for protection from free radicals and involved in muscle generation (Hostetler et al., 2003).
Injectable supplementation advantages include the targeted delivery of known trace mineral elements. When growing heifers were administered half of the manufacturers recommended dose of trace mineral supplement, at three different time points, no differences were observed in age at puberty or attainment of pregnancy (Arthington et al., 2014). In contrast, when trace mineral injections were administered 30 d before calving and 30 d before breeding with the addition of an artificial insemination (AI) breeding system, a greater proportion of those females receiving the injectable supplement became pregnant to AI compared with cows not receiving injectable supplement (60.2 percent and 51.2 percent, respectively; Mundell et al., 2012).
To date, few studies have evaluated the use of injectable mineral supplements administered before breeding while utilizing a natural service breeding system on commercial beef operations. Data currently available regarding injectable trace mineral supplements are conflicting with regards to their effect on pregnancy attainment, weaning weights and calving distribution. Therefore, the objective of this study was to evaluate blood mineral levels before treatment administration on a subset of cows as well as evaluate the effects of injectable trace mineral supplements administered 30 d before the start of the breeding season on pregnancy rates, calf weaning weights, and calving distributions.
- Document the effects of trace mineral supplements on reproductive performance in commercial beef herds.
- One thousand five-hundred nineteen postpartum commercial beef cows (Herd 1: n = 146; Herd 2: n = 501; Herd 3: n = 460, Herd 4: n = 204, and Herd 5: n = 132) were stratified within herd by d postpartum, then randomly assigned to receive one of two treatments: 1) Cows received no additional treatments prior to bull turn out (CON; n = 755); or 2) Cows were administered 6 mL of an injectable trace mineral supplementation (60, 10, and 15 mg/mL of zinc, manganese, and copper, as disodium EDTA chelates, and 5 mg/mL of selenium as sodium selenite) subcutaneously on d -30 relative to bull turn out (TM; n = 764).
- Natural service bulls were turned out to all cows 30 d after treatment administration and remained with cows for the duration of the producer defined breeding season. Transrectal ultrasonography or rectal palpation was used to determine the presence of a viable fetus at least 30 d after the end of the breeding season by a herd veterinarian. Calf weaning weights were collected at the time of weaning for the year of administration to determine if any effects of injectable trace mineral supplementation administered to the cow affected the weight of the calf at her side. At the time of calving, birth date and calf sex were recorded.
- Analysis of data indicate that pregnancy rates did not differ (P = 0.29) between groups of females in the CON and TM groups. Weaning weights of calves on the side of cows receiving treatments also were similar (P = 0.90). At calving, mean calving date was not different (P = 0.99) for those calves born from TM cows or control cows. When evaluating the distribution of calves born in the calving season by 21-d increments, the proportion of calves born in the first 21, 22 to 42, or more than 42 d of the calving season were similar (P = 0.40) between groups.
- Increase producer, extension personnel, and veterinarian knowledge and awareness of mineral status, around the state of North Dakota, generated by the interpretation and reports of the baseline mineral samples.
- On d -30 relative to bull turnout, blood samples were collected from a subset of eight to 10 cows within each herd. Blood was collected via jugular venipuncture for analysis of baseline mineral status. Blood samples were analyzed for concentrations of cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), Molybdenum (Mo), selenium (Se), and zinc (Zn).
- Samples of total mixed rations were collected and placed in bags for herds 3 and 4 while supplemented hay samples were collected for herd 1, representing the animals still in confinement prior to pasture/bull turn out. Water samples were also collected from any and all available water sources for each herd.
- Blood, feed, and water samples were collected at each operation. No differences (P = 0.11) were observed in the blood mineral levels between treatments for cobalt, copper, iron, manganese, molybdenum, selenium, or zinc before treatment administration. Since blood was collected before treatment administration, results are as anticipated. Herd blood values averages, water samples, and feed samples values are included in the following tables.
- Measure the change in management considerations (i.e. changes in mineral supplementation, use of injectable products, etc.), and the quality of life of those cooperating producers.
- These measurements will be evaluated with the use of survey based questionnaires focusing on learning and behavior based evaluations. Surveys will include before and after type questions as well as assessments of actions or management strategies employed after year one of the project is complete. Producers will be the targeted audience for this type of evaluation as the producers may likely have the ability to increase profitability.
- Survey questions are in the process of being created for distribution to cooperating producers.