Grad Student Competition
Describing the consumption of a granular mineral supplement containing chlortetracycline by gestating beef cattle on pasture
| Date/Time: |
9/13/2024
09:15
|
| Author: |
Madeline G McKnight |
| Clinic: |
Mississippi State University |
| City, State, ZIP: |
Starkville, MS 39759 |
M. McKnight, BS
1
;
W. I. Jumper, DVM, PhD, Dipl. ACVPM
2
;
K. Harvey, MS, PhD
1
;
M. Drewery, BS
3
;
C. Potts, BS
3
;
J. Cordero, MS
3
;
J. Russell, MS, PhD
4
;
D. R. Smith, DVM, PhD, Dipl. ACVPM, Dipl. Epidemiology
2
;
1Department of Animal and Dairy Sciences, Mississippi State University, Starkville, Mississippi, 39759
2Department of Pathobiology and Population Medicine, Mississippi State University, Starkville, Mississippi, 39759
3Prairie Research Unit, Mississippi State University, Prairie, Mississippi, 39759
4Zinpro Corporation, Eden Prairie, Minnesota, 55344
Introduction:
The objective of this study was to explore the consumption frequency of a granular, chlortetracycline (CTC)-containing mineral supplement offered free-choice to beef cows on pasture.
Materials and methods:
A total of 94, nonlactating, pregnant, crossbred beef cows were randomly assigned to 1 of 3 pasture groups. Each group was equipped with a portable, self-contained feeding unit (SmartFeed; C-Lock, Inc.) used to record individual animal supplement intake and frequency. Cows were offered dried distillers’ grains with NaCl for 14 days of acclimation (mean intake=1.54 kg/day) before transitioning to a commercially available granular mineral containing CTC (6,160 mg/kg) on day 0 for 162 days from May 18-October 26, 2023.
Results:
According to label instructions, each cow should be fed mineral supplement such that they consume 1.1 mg CTC/kg of body weight daily. Mean supplement consumption throughout the study was 87 g mineral/cow/day, or 0.54 g CTC/cow/day. The mean number of consecutive days that a cow did or did not consume any amount of mineral was 2.4 and 3.1, respectively. On average, 47% of cows consumed mineral on any given day of the study, with a maximum of 79% and a minimum of 7%. Using individual body weights, expected total CTC-containing mineral intake for the trial period was calculated for each cow individually. In total, 43% (40/94) of cows consumed an adequate amount of mineral throughout this study to receive the label-indicated dose of CTC.
Significance:
Results of this study show that feeding a granular CTC-containing mineral supplement free-choice is not an effective method of ensuring all cattle consume the label-indicated dose of CTC.
