Alternative trace mineral supplementation strategies for beef cattle
Date
2024-09-25
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
0009-0008-8404-185X
Type
Thesis
Degree Level
Masters
Abstract
This study evaluated an injectable trace mineral (ITM) source containing Cu, Mn, Se, and Zn (Multimin®90) administered to gestating beef cows also receiving a free-choice 2:1 mineral supplement. Two hundred and eight multiparous and primiparous cross-bred beef cows were blocked by age (avg. 4 yr. old) and stratified by BW (621 kg ± 96.6 kg), which were randomly allotted to 1 of 2 treatments, either i) ITM + inorganic, granular 2:1 trace mineral free-choice; or ii) inorganic, granular 2:1 trace mineral free-choice alone (CON). A cross-over design was used for the 2-yr study and cows in yr 2 (n = 202) were allocated to the other trt group. The ITM was administered at 4 wks pre-calving and 4 wks pre-breeding. Body weight and body condition score (BCS) were evaluated at injection times and pregnancy diagnosis in the fall. Blood serum mineral concentrations (n = 40 per trt) were analyzed at 4 weeks pre-calving, 4 weeks pre-breeding, and pregnancy diagnosis . Cows grazed grass-legume pastures during summer and had access to well and dugout water sources. Blood serum mineral concentrations at 4 weeks pre-calving (P > 0.05), 4 weeks pre-breeding (P > 0.15), and pregnancy diagnosis (P > 0.09) did not differ between trt groups. Copper levels at pregnancy diagnosis tended (P = 0.09) to be higher for ITM cows compared to CON cows. Cow BW, BCS, and days pregnant did not differ (P > 0.15). Over 2-yr, pregnancy rates tended (P = 0.09) to be higher for the ITM group compared to the CON (93.6% vs 88.6%). Calves born to ITM and CON cows did not differ for birth weight (P = 0.72), Julian birth date (P = 0.18), or age at weaning (P = 0.22), average daily gain (P = 0.26), or adjusted 205 d wean weight (P = 0.33). CON calves tended (P = 0.07) to be heavier at weaning. Weaning weight and age at weaning were adjusted at 205 d and resulted in no differences between trt groups (P = 0.33; P = 0.22). This result suggests that CON calves were older in age and heavier at the time of weaning as there was a higher percentage of calves born from d 0 to 41 in the calving season compared to ITM calves (79% CON vs 73% ITM). Study results suggest that pregnancy rate and Cu status during the grazing season may be improved with the use of an ITM supplement, although more research is warranted.
Description
Keywords
beef cattle, injectable trace mineral, productivity
Citation
Degree
Master of Science (M.Sc.)
Department
Animal and Poultry Science
Program
Animal Science