TITLE:
Assessment of Lactational Performance in Dairy Cows Receiving a Rumen Protected B Vitamin Blend during Lactation: Part 2: A Regression Analysis of 50 Studies
AUTHORS:
Essi Evans, Helene Leclerc, Emilie Fontaine, Ousama Al Zahal, Elizabeth Santin
KEYWORDS:
Meta-Regression, Dairy Nutrition, Rumen Protection, B Vitamins
JOURNAL NAME:
Open Journal of Animal Sciences,
Vol.11 No.4,
September
30,
2021
ABSTRACT: A previous series of meta-analyses demonstrated that a protected blend of
B vitamins (RPBV: folic acid, B12, pyridoxine,
pantothenic acid, and biotin; Jefo, St. Hyacinthe, QC, Canada) improved
milk fat and protein yield, with variation in the extent of the response. These
results represent additional analyses of the same dataset to determine if the
degree of response to RPVB on milk, fat and protein yield might be related to the level of production,
lactation number, or
days in milk (DIM). Results from 50 on-farm switchback trials conducted in 7 countries between 2005 and 2015
were included in the analysis. All herds participated in monthly milk recording
services, and all were Holstein herds. A total of 6483 cows, averaging 163 DIM
on the first test date, participated in the studies. Data were analyzed using
regression models that accounted for the effects of trial, period, days in milk
(DIM) and lactation number on milk and component yield. Milk yield and fat yield increased
with B vitamin inclusion, and the extent of change was determined to increase
with lactation number (P -protected B vitamin blend
= 4.05 + [0.917 × control milk] -[0.0063 × DIM] + [0.246 × Lactation
number] (R2 = 0.798) The use of regression models allows changes in
milk, fat and protein yields with the rumen-protected B vitamin blend to be more accurately
predicted.