A meta-analysis and meta-regression of the effects of vitamin E supplementation on serum enrichment, udder health, milk yield, and reproductive performance of transition cows

Abstract

Vitamin E is an essential nutrient for cows, but the effect of vitamin E supplementation is often controversially discussed in the published literature. The main goal of this meta-analysis was to evaluate the effects of vitamin E supplementation on its serum and colostrum enrichment, milk yield (MY), and somatic cell counts (SCC), as well as on various reproductive variables of transition cows, by considering a large set of variables that might influence the responses to vitamin E supplementation. After a broad search in journals and databases with keywords related to transition cows supplemented with vitamin E and appropriate filtering of the results, 36 papers including 53 trials were selected, and their data were extracted into a database. A meta-analysis was conducted on the extracted data. The analysis showed enrichment of serum vitamin E both at parturition (effect size: 2.423) and postpartum (effect size: 0.473), but no effects of vitamin E supplementation on IgG concentration in colostrum (effect size: −0.05) were found. There was a tendency for supplemented cows to produce more milk (effect size: 1.29) during the first month of lactation. Because of large heterogeneity, a meta-regression was performed but none of the presumed influencing factors was identified as a potential variable affecting MY. Milk SCC, as an indicator of udder health, was unaffected by vitamin E supplementation. Vitamin E supplementation tended to decrease the calving to first estrus period (CFP), whereby supplementing Se and taking parity into account in the analysis significantly lowered the CFP. Cows receiving additional vitamin E had, on average, 6.1% fewer cases of retained placenta, whereby Se supplementation and breed were key factors improving the effect of vitamin E to reduce retained placenta. In this regard, breeds other than Holstein responded better and these cows showed a lower incidence of retained placenta. The supplemented cows showed fewer days open (effect size: −0.31), and this improvement was affected linearly by increasing the dosage administered. Also, cows showed fewer services per conception with increasing dosage of vitamin E. In conclusion, this analysis showed that supplementing vitamin E did not affect SCC or colostrum quality but improved reproductive performance of transition cows, an effect consistent with increased levels of serum vitamin E and, for some variables, being modulated by Se supplementation.

Modifiable management practices to improve udder health in dairy cattle during the dry period and early lactation: A scoping review

“…Extending this research to populations of multiparous dairy cows would be beneficial to the mastitis research community. Additionally, a recently published meta-analysis assessed the effects of vitamin E and vitamin E with selenium adjuvants on SCC in milk (Moghimi-Kandelousi et al, 2020), but future work could include other vitamin and mineral products such as β-carotene and vitamin A. Santos et al (2019) conducted a meta-analysis on the effect of a prepartum DCAD on production performance and health of dairy cattle, by means of altering the mineral composition of diets, and found that less than half of included studies reported the effect of DCAD on mastitis.…”

The Physiological Roles of Vitamin E and Hypovitaminosis E in the Transition Period of High-Yielding Dairy Cows

“…Several other factors affect α-Toc availability and its physiological functions in cows, including the source of the α-Toc active substance, other fat-soluble nutrients in feeds, timing and period of supplementation, inclusion of Se, α-Toc content of the basal feeds, and method of administration (e.g., ruminal pellets or premixes in diet, or iv, sc and im injection). Moghimi-Kandelousi et al [151] evaluated the effects of α-Toc supplementation on the serum level, milk yield, and SCC values of transition cows by considering a large set of variables that might influence the responses to α-Toc supplementation. To conduct a comprehensive meta-analysis of α-Toc supplementation effects during the transition period, after a broad search in journals and databases with keywords related to transition cows supplemented with VE and appropriate filtering of the results, 36 papers including 53 trials were selected from 528 publications (from 1979 to 2018), and their data were extracted into a database.…”

High-Dose Vitamin E Supplementation Can Alleviate the Negative Effect of Subacute Ruminal Acidosis in Dairy Cows

“…Studies have shown that dietary VE can scavenge free radicals, enhance antioxidant capacity and immunity, and improve the performance of cows. The study found that a VE supplementation in diets could reduce the MDA content in cells to a certain extent, improve the antioxidant enzyme activity, enhance the antioxidant capacity in the rumen and body of cows, and reduce the inflammatory response [7]. It found that VE could alleviate the rumen oxidation effect, improve the fermentation yield of cows, and change the availability of rumen energy, thus benefiting the growth of rumen microorganisms [8].…”