Peripartum decreases in serum concentrations of vitamins A and E may contribute to impaired immune function in dairy cows. The objectives of this study were to describe peripartum serum concentrations of alpha-tocopherol, beta-carotene, and retinol and their associations with disease risk. On 20 farms over 1 yr, blood samples were collected weekly from 1057 cows from 1 wk before expected calving until 1 wk postpartum. Serum concentrations of alpha-tocopherol, beta-carotene, and retinol, as well as several biochemical variables were measured. Their associations with the risk of retained placenta or clinical mastitis were modeled separately with logistic regression, and the factors associated with the concentration of each vitamin were modelled with mixed linear regression. Differences in vitamin concentrations between 2 batches of sera analyzed 6 mo apart required stratification of statistical analyses. Accounting for the effects of parity, season, and twins, an increase in alpha-tocopherol of 1 microg/mL in the last week prepartum reduced the risk of retained placenta by 20%, whereas serum nonesterified fatty acid concentration > or = 0.5 mEq/L tended to increase risk of retained placenta by 80%. In the last week prepartum, a 100 ng/mL increase in serum retinol was associated with a 60% decrease in the risk of early lactation clinical mastitis. There were significant positive associations of peripartum serum concentrations among each of alpha-tocopherol, beta-carotene, and retinol.

The objective of Trial 1 was to evaluate in dairy cows the effects of dietary supplementation with biotin and a B-vitamin blend on dry matter intake (DMI), milk yield, composition and component yields, total tract nutrient digestion, and plasma metabolites. Twenty-four multiparous Holstein cows averaging 46 +/- 8 d in milk at trial initiation were randomly assigned to treatments in a replicated 4 x 4 Latin square design with 28 d periods. The four treatments were: 1) a control diet (C) with no supplemental B-vitamins; 2) C plus supplemental biotin at 20 mg/d (B); 3) C plus supplemental thiamin (150 mg/d), riboflavin (150 mg/d), pyridoxine (120 mg/d), B12 (0.5 mg/d), niacin (3000 mg/d), pantothenic acid (475 mg/d), folic acid (100 mg/d), and biotin (20 mg/d) (BBVIT1X); 4) C plus supplemental thiamin (300 mg/d), riboflavin (300 mg/d), pyridoxine (240 mg/d), B12 (1.0 mg/d), niacin (6000 mg/d), pantothenic acid (950 mg/d), folic acid (200 mg/d), and biotin (40 mg/d) (BBVIT2X). Intake of DM was increased 0.7 kg/d for B vs. C and BBVIT1X and 1.3 kg/d for B vs. BBVIT2X. Milk yield was increased 1.7 kg/d for B vs. C. For BBVIT1X, milk yield was similar to B and BBVIT2X and tended to be higher than C. Yields of milk protein and lactose but not fat were higher for B than C. For BBVIT1X, milk component yields were similar to B and tended to be higher than C, with the exception of lactose yield where BBVIT1X was higher than C. The objective of Trial 2 was to evaluate DMI and milk yield, composition and component yields by dairy cows fed diets supplemented with either 40 mg/d biotin or the B-vitamin blend (BBVIT1X) compared to cows supplemented with 20 mg/d dietary biotin. Neither the 40 mg/d biotin treatment nor the B-vitamin blend enhanced lactation performance over the 20 mg/d biotin treatment. Biotin efficacy in short-term trials suggests that biotin may improve milk yield directly via effects on intake and (or) nutrient metabolism rather than indirectly via improved hoof health. More research is needed to determine the mode of action for supplemental dietary biotin.

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Ten patients with ulcerative colitis, all of whom were non-smokers, presented with a productive cough. In six, the chest radiograph was normal and cough was the only symptom; three of these patients had a minor obstructive ventilatory defect on testing. Four patients complained of exertional dyspnoea and had both an abnormal chest radiograph with bilateral pulmonary shadows and a mixed obstructive and restrictive ventilatory defect. Bronchial epithelial biopsies from four patients (two with and two without pulmonary shadows) revealed basal reserve cell hyperplasia, basement membrane thickening, and submucosal inflammation, changes more usually associated with cigarette smoking. Inhaled beclomethasone diproprionate relieved cough in seven patients. The occurrence of airway epithelial disease in association with ulcerative colitis raises the possibility of a systemic mechanism affecting both bronchial and colonic epithelium. It does not seem likely that sulphasalazine was the cause of the pulmonary syndrome in these subjects.