Research Summary - 2
Impact of administering an oral Solanum glaucophyllum/calcium bolus after calving on early lactation milk production and risk of herd removal - preliminary analysis
| Date/Time: |
8/28/2026
15:00
|
| Author: |
Luciano Caixeta |
| Clinic: |
University of Minnesota |
| City, State, ZIP: |
Saint Paul, MN 55108-2020 |
E. Shepley, MS, PhD
1
;
S.M. Godden, DVM, DVSc
1
;
S. Davis, DVM
1
;
L.S. Caixeta, DVM, PhD
1
;
M. Ruch, BS
1
;
R. Leite, DVM (pending)
1
;
1Department of Veterinary Population Medicine, University of Minnesota, Saint Paul, MN 55108
Introduction:
Colostrogenesis and the onset of lactation lead to a rapid decline in blood calcium (Ca), requiring cows to rely on homeostatic mechanisms, namely gastrointestinal absorption and bone mobilization, to meet these increased demands. The resulting hypocalcemia has been associated with decreased milk yield, occurrence of disease events, and increased risk of leaving the herd. A common strategy to prevent these Ca drops is the administration of oral Ca boluses immediately after calving. While many oral calcium boluses effectively manage transient hypocalcemia in the first 48 h postpartum, they often fail to address dyscalcemia on day 4. To address this, a bolus was developed incorporating calcium salts for mineral support alongside Solanum glaucophyllum (SG) leaf to stimulate intestinal calcium absorption via the release of 1,25-dihydroxyvitamin D. The inclusion of SG is expected to increase Ca concentrations for up to 96 h. The objective of this study was to evaluate the effects of administering a Solanum glaucophyllum/calcium bolus at calving on early lactation milk yield and risk of herd removal in multiparous dairy cows, compared with a commercially available Ca bolus or no calcium supplementation at calving.
Materials and methods:
A randomized controlled clinical trial was conducted on 8 commercial Holstein dairy herds (range: 800 to 6,700 cows/herd) located in the Upper Midwest. Multiparous cows were block-randomized by parity and expected calving week to one of three treatments. Cows in the GB treatment were provided with two boluses containing Solanum glaucophyllum and calcium salts (Goff-Bol, Silberhorn Animal Health) as soon as possible after calving, depending on the farm’s fresh cow management system. Cows in the BK group received one calcium salt bolus (Bovikalc, Boehringer Ingelheim) as soon as possible after calving and a second bolus 12-24 h later. Lastly, cows on the NT group received no bolus treatment after calving. A total of 1,870 eligible cows were enrolled into the study – 591 GB, 629 BK, and 650 NT. Cows were followed through early lactation using each farm’s herd management software. Outcomes included first DHIA test-day milk yield and herd removal risk in the first 30 DIM. Data were analyzed using a mixed linear model for milk yield and a Cox proportional hazards model for time-to-removal. Both models included the fixed effect of treatment, parity (2, 3, or 4+), number of calves born (1 or 2), previous days carrying calf, milk yield at dry-off, DIM at last milk measure before dry-off, and DIM at first milk test of the new lactation. Farm was accounted for as a clustering factor, included as a random effect in the linear mixed model and as a robust variance cluster term in the Cox proportional hazards model.
Results:
Average (Std. Dev.) DIM at the first test was 18.1 (11.7), 16.9 (11.6) and 17.6 (11.6) DIM for GB, BK, and NT groups, respectively. Milk yield at first DHIA test was highest in GB cows (90.6 lb; 95%CI: 78.0, 103.2), followed by NT (89.5 lb; 95%CI: 77.0, 102,1) and BK (87.1 lb; 95%CI: 74.5, 99.7). Cows in the GB group produced 3.5 lb (95%CI: 0.2, 6.8) more than BK cows (P = 0.03) and 1.05 lb (95%CI: -2.14, 4.27) more than NT cows (P = 0.72). Cows in the BK group also had a 2.5 lb (95%CI: -5.7, 0.8) numerically lower yield at first DHIA testday than NT cows (P = 0.17). Overall, 38 (6.4%), 29 (4.6%) and 26 (4.0%) of cows were removed from the herd in the first 30 DIM in the GB, BK, and NT groups, respectively. Herd removal risk was 35% lower for BK compared to GB (Hazard ratio (HR): 0.65; 95%CI: 0.46, 0.90; P = 0.01) and 47% lower for NT compared to GB (HR: 0.63; 95%CI: 0.38, 1.05; P = 0.08).
Significance:
In this preliminary analysis, cows in the GB group had the highest milk yield at the first DHIA test, with BK and NT cows producing slightly less. However, BK and NT cows had a lower risk of herd removal by 30 DIM compared to GB cows. Investigators are continuing to collect and will report health and production data for the first 180 DIM.
