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The influence of physical stress on the plasma concentration of the acute-phase proteins serum amyloid-A (SAA) and haptoglobin (Hp) was studied in 10 calves. Two different stress levels were created by housing two groups of five calves, each on different types of floor. The stress level was assessed by studying videotapes of the animals, and, subsequently, by quantifying the problems related with moving across the pens and the time the calves spent lying down and standing. Plasma concentrations of Hp, SAA, aldolase, and cortisol were measured in blood samples obtained by jugular venepuncture. Plasma SAA concentrations were significantly (p < 0.001) elevated in animals housed on the floor type associated with the highest level of physical stress, although the concentrations were within the normal range for healthy adult cattle. Hp concentrations were not elevated. The floor type did not alter the stress related biochemical variables aldolase and cortisol. It is concluded that plasma SAA concentrations rise upon physical stress, whereas Hp concentrations do not change. The absence of a significant difference in aldolase or cortisol concentrations indicates that the difference in the level of neuro-endocrine stress between the animals housed on the two floor types is only minimal. Consequently, SAA is suggested to be a sensitive variable to assess physical welfare in calves.

Our objective was to study the effects of dietary-induced insulin enhancement during and after lactation on the reproductive performance of primiparous sows. During a 21-d lactation period, 48 sows were allotted to a 2 × 2 factorial experiment. Treatments were feeding level (high or low; 44 MJ or 33 MJ NE/d) and dietary energy source (fat or starch). After weaning, all sows received the same amount of feed (31 MJ NE/d from weaning to estrus and 17.5 MJ NE/d from breeding until slaughter) of the same energy source as fed during lactation. On d 7, 14, and 21 of lactation and d 22 (weaning), blood samples were taken every 12 min for 12 h and analyzed for plasma glucose, insulin, and LH. Sows were slaughtered on d 35 of the subsequent pregnancy, and ovulation rate was assessed. During lactation, postprandial plasma glucose and insulin concentrations were higher for sows fed the starch diet than for those fed the fat diet (P < .001), whereas feeding level had no effect. Basal and mean LH concentrations were not affected by treatments. The LH pulse fre-

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