A trial was conducted to determine the effect of maternal supplementation of Se on transfer of Se to the fetus during late gestation. Holstein cows were randomly assigned at dry-off to receive no Se or 3 mg/d of supplemental Se as selenite delivered via an intraruminal bolus. Supplementation significantly increased concentrations of Se in blood of dams at parturition. Similarly, calves of cows that were supplemented with Se had higher Se in blood and liver. Colostral concentrations of Se were increased by maternal Se supplementation; Se increased in the casein fraction. The Se concentrations in blood, plasma, and liver of calves were positively correlated with the Se concentrations in plasma of the dam at parturition. Concentrations of Se in colostrum and in calf liver also were closely correlated. Concentrations of Se in calf liver at d 42 were closely correlated with concentrations of Se in liver at birth. Maternal supplementation of Se increased Se reserves in the liver of the newborn and in colostrum. Carryover effects of Se supplementation of dams were evident in calves at 42 d of age.
A total of 22 dairy dromedary camels under intensive conditions in late lactation (275±24 days) were used to study the relationship between external and internal udder morphology and machine milking performances. Measurements of udder and teat morphology were obtained immediately before milking and in duplicate. Individual milk yield, lag time and total milking time were recorded during milking, and milk samples were collected and analyzed for milk composition thereafter. Cisternal and alveolar milk volumes and composition were evaluated at 9 h milking interval. Results revealed that dairy camels had well developed udders and milk veins, with medium sized teats. On average, milk yield as well as milk fat and protein contents were 4.80±0.50 L d-1, 2.61±0.16% and 3.08±0.05%, respectively. The low fat values observed indicated incomplete milk letdown during machine milking. Lag time, and total milking time were 3.0±0.3, and 120.0±8.9s, on average, respectively. Positive correlations (p<0.05) were observed between milk yield and udder depth (r=0.37), distance between teats (r=0.57) and milk vein diameter (r=0.28), while a negative correlation was found with udder height (r=-0.25, p<0.05). Cisternal milk accounted for 11% of the total udder milk. Positive correlations were observed between total milk yield and volume of alveolar milk (r=0.98; p<0.001) as well as with volume of cisternal milk (r=0.63, p<0.05). Despite the low udder milk storage capacity observed in dairy camels, our study concluded that the evaluated dromedary sample had adequate udder morphology for machine milking. Finally, positive relationships were detected between milk yield and udder morphology traits of dairy camels.
Developmental changes of Cu, Mn, Zn, and Se in fetal liver and kidney and the intracellular distributions were determined. Fetuses were obtained from crossbred beef heifers (n = 25) that were slaughtered at different stages of pregnancy. Fetal age was estimated from crown to rump measurements. Selenium concentration of fetal liver increased from d 145 to 195 but decreased from d 195 to 245. Fetal age did not affect Cu, Mn, or Zn in fetal liver and kidney or Se in kidney. Bone Ca significantly decreased with fetal age, but neither bone P nor Ca:P ratio changed. Liver Zn concentrations were correlated negatively with kidney Mn but positively with liver Se. Within fetal liver, the crude nuclear fraction had the largest amount of Cu, and the largest amounts of Zn and Mn were in the cytosolic fractions. The ribosomal fractions contained the least Cu, Zn, and Mn. Results indicate the normal changes that occur in tissue concentrations of minerals in the developing bovine fetus. Storage of minerals in fetal tissue reflects fetal demands for growth and the ability of the dam to transfer minerals.
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