Effect of supplemental Vitamin E on the performance, metabolic Effect of supplemental Vitamin E on the performance, metabolic profiles, and immune responses of dairy calves. profiles, and immune responses of dairy calves.

Summary Forty-six Holstein heifer calves were used frolo birth to 3 rno to study the effect of supple:nental vitamin E at 1400 or 2800 mg dl-a.-tocopherol acetate given orally at weekly intervals or 1400 mg dl-a-tocopherol by intr!i:n L1Scular injection. Weekly starter consumption was 10 to 27 % more (P=.12) and weekly weight gains were 9 to 25% more (P=.13) in supplemented calves.


Summary
Forty-six Holstein heifer calves were used frolo birth to 3 rno to study the effect of supple:nental vitamin E at 1400 or 2800 mg dl-a.-tocopherolacetate given orally at weekly intervals or 1400 mg dl-a-tocopherol by intr!i:n L1Scular injection.
Weekly starter consumption was 10 to 27 % more (P=.12)and weekly weight gains were 9 to 25% more (P=.13) in supplemented calves.Creatine phosphokinase activity was negati vely cor-related with sel'urn tocopherol concentrations, indicating a subclinical muscular dystrophy in unsupplemented calves.Lymphocyte stimulation indices were positively correlated with serum tocopherol concentration.Calves given high level of oral supplementation had higher Ig:vl antibody concentration.It was concluded that supplement;ll vitamin E is beneficial for calves ['eared on conventional complete starters to increase disease resistence and to obtain optim urn performance.

Introduction
Modern calf management systems have shown a trend toward confined feeding of complete rations contai ning both grain and forage and less access to past ures.Under such conditions, several factors affect vitamin E requirements, including inadequate vitamin E in feedstuffs, stress conditions, and interrelationships with certain other nutrients in the diet.In calf rations, feedstuffs alone may not provide a sufficient amount of alpha-tocopherol, which is the most biologically active forln of vitamin E.
Recent studies with laboratory animals and other animals have shown that vitamin E at levels much higher than those presently recommended enhances im mune responses.
The objecti ve of the present research was to st udy the effect of supplernental vitamin E on the general performance, metabolic profiles, and immune responses of dairy calves from birth to 3 mo under normal herd management conditions.

Experimental Procedures
Forty-six Holstein heifer calves were used in the experiment.Calves were allotted to one of 3 treatments: (1) 0 mg 2) 1400 mg and 3) 2800 mg of ell-a -tocopherol acetate fed orally at weekly intervals with a nipple bottle.Later calves were also allotted to Ii 4th treatment, which was 1400 mg of dl-Ct-tocopherol given by intra;n 15cular injection at weekly intervals.
Calves were fed colostrum for the first 3 days and then milk at 8% of birth weight until weaning at 6 wk.Water and a complete calf starter (Tables 1 and 2) were always available to the cal ves.Cal ves were ho used in fi berglass hutches throughout the experiment.Weight gains wet'e recorded weekly.Fecal consistencies were scored twice daily.

Results and Discussion
Data on the performance and imm une responses are in Table 3.
Although statistically not significant, weekly weight gains were 9 to 25% greater and Neekly starter consumption was 10 to 27 % more in supplemented calves.Fecal scores were the saine for all cal ves.Lymphocyte stim uhl.tion indices, considered to be the laboratory cOl'relates for cell-mediated imm une responses, were positively correlated with serum-tocopherol concentr!:.l.tions.This indicated th!:.l.t supple!nented calves possibly had developed a better immunoco,npeteflcy dUl'ing theil' fir.~t weeks of life and thus were relatively more protected again~t dise.l1ses.
Calves given a higher level of oral supple:nentation had higher Ig:vJ antibodies, suggesting capability for a better primary immune response.

Table 1 .
Ingredient composition of calf starter 1