M. Morgante et al., Effect of administration of vitamin E and selenium during the dry period on mammary health and milk cell counts in dairy ewes, J DAIRY SCI, 82(3), 1999, pp. 623-631
The effect of parenteral administration of two subcutaneous injections of v
itamin E and Se (5 mg and 0.1 mg/kg of body weight, respectively) during th
e dry period on the mammary health and milk somatic cell counts of 25 dairy
ewes was investigated. Supplementation reduced somatic cell counts (5.4 vs
. 6.0 log(10)) during the subsequent lactation but had no effect on the inc
idence of clinical mastitis (4% vs. 6%) and intramammary infections (9.0% v
s. 11.3%). Furthermore, the administration of vitamin E and Se was associat
ed with differences in differential cell counts of milk samples (macrophage
s, 48.8% vs. 38.4%; polymorphonuclear neutrophils, 40.1% vs. 50.7%; and eos
inophils, 0.7% vs. 1.4% for control ewes and ewes receiving supplements, re
spectively). The administration of these supplements also increased erythro
cyte glutathione peroxidase activity (139.5 vs. 86.3 U/ml of packed cell vo
lume) and the percentage of blood neutrophils that reduced nitroblue tetraz
olium after bacterial extract stimulation (48.6% vs. 38.7%). Parenteral adm
inistration of vitamin E and Se to ewes during the dry period appeared to h
ave influenced mammary gland status during the subsequent lactation and par
ticularly total and differential milk cell counts.