Pregnant ewes were chronically exposed to thermoneutral (TN; 20 degrees C, 30% relative humidity) or hot (H; 40 degrees C 9 h/d, 30 degrees C 15 h/d, 40% relative humidity) environments between d 64 and 136 to 141 of pregnancy. They were sampled for blood at 14-d intervals during this period for measurement of plasma metabolites and hormones, then slaughtered and dissected to measure conceptus weights, dimensions and fetal organ weights. Rectal temperatures of H ewes were elevated .3 to 1.0 C degrees above those of TN ewes throughout the experiment. Voluntary feed intakes were not altered by heat exposure except after 120 d of pregnancy, when feed intake was about 25% lower (P less than .10) by H than by TN ewes. Blood 3-hydroxybutyrate concentrations were not affected by heat, but plasma glucose concentrations were greater in H than in TN animals after 120 d (P less than .05). Placental weight, reduced by 54% (P less than .001) by heat exposure of ewes, was correlated positively with fetal weight and correlated negatively with fetal/placental weight ratio, fetal brain/liver weight ratio and fetal relative heart weight. Late in pregnancy, plasma concentrations of progesterone, cortisol and placental lactogen were reduced (P less than .01) in H ewes, whereas triiodothyronine levels were markedly lower (P less than .03) at all stages of pregnancy. Plasma concentrations of prolactin were elevated dramatically (P less than .01) and a modest increase (P less than .03) in somatotropin levels was recorded in H ewes. These results are consistent with our hypothesis that heat-induced fetal growth retardation is secondary to a primary reduction in placental growth; this could be mediated partly by reduced peripheral activity of thyroid hormones. Heat-induced reductions in secretion of progesterone and ovine placental lactogen more likely were a consequence than a cause of placental stunting.

No abstract

Trans-10, cis-12 conjugated linoleic acid (CLA) reduces milk fat synthesis in sheep in a manner similar to that seen in dairy cows, but its effects on cheese yield and flavor are unknown. Additionally, when dietary energy supply is restricted, CLA can increase milk and milk protein yield, which may alter cheese yield and eating quality. The objectives of the study were to examine the effects of supplementing ewe diets with a rumen-protected source of CLA at a high and low dietary energy intake on milk fat and protein synthesis and on cheese yield and eating quality. Sixteen multiparous ewes were randomly allocated to 1 of 4 dietary treatments: a high (6.7 Mcal of metabolizable energy/d) or low (5.0 Mcal of metabolizable energy/d) feeding level that was either unsupplemented or supplemented with 25 g/d of a lipid-encapsulated CLA (to provide 2.4 g/d of CLA) in each of 4 periods of 21 d duration in a 4 x 4 Latin square design. There was no effect of treatment on milk yield (g/d), but milk fat percentage and milk fat yield were reduced by 23 and 20%, respectively, in ewes supplemented with CLA. Milk fatty acid concentration (g/100 g) of chain length < C16 was decreased and > C16 was increased in milk and cheese following CLA supplementation, whereas decreasing the feeding level increased fatty acids > or = C16. Milk fat contents of CLA were 0.01 and 0.12 g/100 g of fatty acids for the unsupplemented and CLA-supplemented treatments, respectively, whereas cis-9, trans-11 CLA was unaffected by CLA supplementation. There was no main effect of treatment on cheese yield, which was 0.11 +/- 0.001 kg of cheese/kg of milk, but cheese yield was highest, at 0.12 +/- 0.001 kg/kg, when made from milk of ewes fed the high feeding level + unsupplemented treatment. Cheese made from the milk of ewes supplemented with CLA, compared with the unsupplemented diet, was rated (scale 0 to 10) higher in the creaminess (2.1 vs. 1.4; SEM 0.15) and less oily (0.8 vs. 1.3; SEM 0.17) attributes, and was preferred overall (4.5 vs. 3.9; SEM 0.21). Cheese produced from sheep on the high vs. low feed level was rated less yellow (2.8 vs. 4.2; SEM 0.11), less salty (1.9 vs. 2.3; SEM 0.15), and more sour (1.5 vs. 1.1; SEM 0.13). We concluded that the effect of feeding level on animal performance and cheese characteristics was small, whereas supplementing the diets of ewes with a ruminally protected CLA source reduced milk fat yield, did not affect cheese yield, and beneficially altered the flavor characteristics of the cheese.

Flaviviral diseases such as yellow fever, Japanese encephalitis (JE) and dengue hemorrhagic fever cause enormous morbidity and mortality worldwide. There is an urgent need for alternative technologies for mass vaccination against these and other diseases, particularly in the developing world. Here, we administered a live attenuated, chimeric JE vaccine (ChimeriVax)-JE) to nonhuman primates by skin microabrasion and intradermal delivery using microneedles. Both cutaneous delivery methods induced mild viremia similar in magnitude to that observed following subcutaneous (SC) injection. The duration of viremia induced by cutaneous delivery (5-7 days), however, was substantially longer than via SC (0-3 days). In addition, mean neutralizing antibody titers in cutaneous delivery groups were up to 7-fold greater than via SC injection. There were no safety issues identified and both cutaneous delivery methods appeared to be well tolerated. Thus, cutaneous delivery may represent a minimally-invasive alternative approach for flavivirus vaccines that more closely resembles the natural route of viral infection.