Research Summary - 2
Comparison of an oral Solanum glaucophyllum/calcium bolus or calcium boluses on periparturient calcium concentration, metabolic diseases, milk production, cull rate and rumination in dairy cows.
| Date/Time: |
8/28/2026
14:15
|
| Author: |
Jesse P Goff |
| Clinic: |
Accunutrition |
| City, State, ZIP: |
Ames, IA 50010 |
J.P. Goff, DVM, PhD
1
;
S. Earnest, DVM
2
;
1Accunutrition, Ames, IA 50010
2ProAGtive Technologies, Sun Prairie, WI, 53590
Introduction:
The incidence of clinical hypocalcemia or milk fever has been greatly reduced by the use of anionic or phosphorus binder prepartum diets. However, subclinical hypocalcemia (blood Ca < 2.0 mM in early lactation), and dyscalcemia (blood Ca < 2.2 mM at 4 DIM) remain significant in cows fed prepartum diets effective at preventing milk fever. Solanum glaucophyllum (SG) is a plant that contains glycosides of 1,25-dihydroxyvitamin D3 in its leaves. Rumen bacteria cleave off the glycosides liberating the bioactive 1,25-dihydroxyvitamin D capable of activating transcellular Ca transport in intestinal cells within 12 hours of administration. Oral boluses were developed that combined SG leaf with Ca (Goff-Bol, Silberhorn Animal Health) and their efficacy in reducing hypocalcemia and health issues in multiparous cows was tested against a commercial oral Ca bolus (Bovikalc, .Boehringer Ingelheim).
Materials and methods:
Multiparous Holstein cows from a single dairy were matched by parity and previous ME 305 milk yield. One cow from each of the 211 pairings was administered 2 SG / calcium boluses (SG Bol) at calving which provided Beta-glycoside of 1,25-dihydroxyvitamin D3 and 76 g soluble Ca. The second cow in the pair received 3 doses of a 43 g Ca/ bolus (Ca Bol), administered at calving, 12 -24 and 24 -36 hours after calving. Cows were fed an anionic diet with urine pH between 6 and 6.7 and the bolus treatments were administered within 1.5 hours of calving. Blood was collected from a subset of cows (9 SG Bol and 5 Ca Bol) to determine blood Ca concentrations at 0, 2, 12, 24, 36, 48, 72, and 96 hours after calving and 1st bolus administration (administered within 1.5 hours of calving). Milk production was recorded daily and summed weekly for the first 30 DIM. Health events were recorded for each cow and rumination monitor health alerts based on decreased rumination after calving were recorded (CowManager, Harmelen, NL) The effects of treatment on plasma Ca concentrations and milk yield were evaluated using a mixed model for repeated measures in SAS. Chi-square tests (or Fisher’s exact test when any cell values were < 5) were used to compare treatment effects in binary (yes/no) health data.
Results:
The average parity of the cows was 3.3. One SG Bol cow was not pregnant and was not included in the study. SG Bol cows had significantly higher (P< 0.02) blood Ca concentrations at 36, 48 and 72 hours after calving than Ca Bol cows. The SG Bol cows average plasma Ca concentration exceeded 2.2 mM by 36 hours and was 2.43 mM at 96 hrs. Ca Bol cows average blood Ca concentration remained below the subclinical hypocalcemia cut point at 48 hours and was 2.26 mM at 96 hours. Across all parities no differences were observed in milk production across treatments during the first 30 DIM. Rumination monitor health alerts the 1st 10 DIM and ketosis incidence were significantly reduced (P< 0.05). There was a tendency for SG Bol cows to be less likely to die or be culled in the 1st 60 DIM (P= 0.10), to exhibit less diarrhea (P=0.09), and suffer fewer cases of milk fever (P= 0.08). No significant effects were observed on incidence of metritis or retained placenta.
Significance:
Both boluses used in this study supplied readily soluble Ca salts that can elevate ionized Ca concentration at the apical surfaces of rumen and intestinal epithelium to permit paracellular absorption of Ca. Only a small portion of the administered Ca is absorbed via this route but it improves plasma Ca for several hours each time a bolus is administered. The SG leaf glycosides of 1,25-dihydroxyvitamin D are capable of activating transcellular Ca absorption starting about 12 hours after administration which is much more efficient than paracellular Ca absorption. The transcellular Ca absorption is sustained for up to 96 hours after administration to the cow. This is likely responsible for reduced incidence of subclinical hypocalcemia and dyscalcemia in SG Bol cows. Dyscalcemia has been shown to negatively impact cull rates, milk production, and fertility of cows And in this study, improved blood Ca concentration is likely responsible for improvements in some health parameters of the cows in early lactation.
