Results from 4 switchback field trials involving 608 cows were combined to assess the effects of a protected B vitamin blend (BVB) vs 10 mg of unprotected biotin upon milk yield (kg), fat %, protein %, fat yield (kg) and protein yield (kg) in primiparous and multiparous cows. Trials consisted of 3 DHIA periods executed in the order control-test-control. Cows from 45 to 300 days in milk (DIM) at the start of the experiment that were available for all 3 periods were included in the analysis. No diet changes other than the substitution of 3 grams/cow/day of the BVB for 10 mg of biotin during the test period occurred. Results from the two control periods were compared to results obtained during the test period by individual cow using a paired T test. Results for all cows showed that the provision of the BVB resulted in increased (P < 0.05) milk, fat percentage (%), protein %, fat yield and protein yield. Analysis by age revealed that milk production and milk protein yield were only improved in mature cows. Milk production had a negative effect upon the magnitude of the increase in milk components. The change in milk yield was greatest in early lactation and declined with DIM. Protein % and fat % increased with DIM in mature cows, but not in first lactation cows. Differences in fat yields between test and control feeding periods did not change with DIM, but the improvement in protein yield in mature cows declined with DIM. These results indicate that the BVB provided economically important advantages throughout lactation beyond those witnessed with biotin, but expected results would vary with cow age and stage of lactation.
Biotin is a noteworthy B vitamin for dairy cows, particularly with respect to maintenance of hoof health [1, 2]. Biotin has additionally been reported to improve milk production, although this response is less consistent. While being investigated as a tool to improve hoof health, Bergsten et al. [
In an analysis of results from studies testing a protected B vitamin blend (BVB) Evans et al. [
Four on-farm feeding experiments were conducted to compare responses to 10 mg/cow/day of unprotected biotin to a protected BVB (Vicomb P+®, Jefo Nutrition Inc., St. Hyacinthe, QC) fed at 3 grams/head/day that likewise provided 10 mg/cow/day of biotin, along with folic acid, pantothenic acid and pyridoxine. A complete description of the product was provided by Sacadura et al. [
Individual cow records were used in the analyses. Cows selected for participation in the study were those that been on a consistent diet for at least 21 days before the first DHIA test, were at least 45 days and no more than 300 days in milk (DIM) at the first test date and were available for all three testing periods. Milk yield (kg), milk fat %, milk protein %, milk fat yield (kg) and milk protein yield (kg) were monitored by cow. Data from the 4 individual trials were combined for the final analysis.
Data were made available from DHIA as comma delineated files and were then transferred into a Microsoft Excel® spreadsheet. Data from period 1 and period 3 were compared by cow to data for period 2 for all variables using a paired, two sided T test using the data analysis function within Microsoft Excel®. Regression models were developed from the data set using Minitab 16 statistical software (Minitab Inc., State College, PA).
Milk, fat and protein yields increased (P < 0.05) with the provision of the B vitamin blend relative to biotin (
vides and that these herds responded positively to the additional vitamins in the BVB, there were differences in responses that could be associated with lactation number. Results showed that the improvement in milk yield and protein yield occurred in mature cows only, and not in the first lactation cows. When only the BVB was provided [
The regression of current milk yield on change in milk yield showed lower yielding cows would be more likely to respond to the BVB than higher producing cows (
Milk yield response to the BVB relative to biotin declined with DIM in mature cows (
In Contrast, milk yield increased (P < 0.05) in multiparous cows given the BVB, suggesting it is not likely that biotin alone was responsible for the change. Sacadura et al. [
Two past studies [9,10] showed the inclusion of the BVB in the diet of lactating cows was instrumental in increasing milk fat % and total yield. Such effects have not been reported with biotin, and may therefore be due to one or more of the other vitamins in the BVB. Milk fat % and yield increased in primiparous and multiparous cows in this study when cows received the BVB, relative to biotin alone.
Ferreira et al. [
with biotin alone.
Milk production declines as lactation advances. The difference in milk yield response to the BVB between test and control periods was significantly reduced by DIM for mature cows (
As noted, the BVB supported greater milk fat % than did supplemental biotin. Equations provided in
In general, milk fat % tends to be lower in high producing cows. Fat percentages are most often lower in early lactation, and increase as lactation advances. The increase in milk fat % in these trials could not (P > 0.05) be related to milk yield (
Findings were similar with milk protein %. Greater protein % values seen with the BVB relative to biotin would only be anticipated to occur when current milk protein % was below approximately 3.20% (
The primiparous cows are still growing, and depositing protein in tissue. It is possible that one of the vitamins is asserting an effect on growth, resulting in differences in protein utilization relative to mature cows. The direction of the change in protein with milk production was positive for cows in lactation 1 (
In most dairy marketing schemes, fat and protein yield are the basis for payment, and effective ingredients with the ability to improve yields of fat and protein benefit dairy producers. As
yields. This effect was also negatively related to level of production (
cows). Current fat yield and DIM explained the largest portion of the total variation in milk fat yield (
Overall, protein yield increased in mature cows only (
Majee et al. [
This analysis shows that supplementation of lactating dairy cows with a rumen protected BVB containing biotin, folic acid, pantothenic acid and pyridoxine improved milk yield, fat %, fat yield, and protein yield in multipa rous and primiparous cows, relative to unprotected biotin. Expected response to the BVB would depend upon level of production, current milk composition and stage of lactation. Data provided from this study can be used to predict outcome from the use of the BVB as changes in production level and herd demographics occur.