The relationship of calfhood morbidity with survival after calving in 25 New York Holstein herds

The association of owner-diagnosed calfhood diseases with the length of herd life after calving was evaluated using data collected prospectively over a ten-year period in 25 New York Holstein dairy herds. Herds selected for the study were milking between 35 and 200 Holstein cows, used dairy herd improvement records, bred cows by artificial insemination unless they needed three or more services, and had regularly-scheduled herd health visits by clinicians from the Cornell University College of Veterinary Medicine. Owners recorded occurrences of dullness, respiratory disease, and scours from birth through 90 days of age for all heifer calves that lived at least 24 h and were to be kept as replacements. Milking herd life was measured as the difference between the age at first calving and the age at death or sale. Data on cows sold when the herd went out of business or still in the herd at the end of the study were censored observations. Cox's proportional hazards model was used for statistical analysis of the data. Controlling for age at first calving, study month of birth, and sire predicted difference for milk, there was no statistically significant association of calfhood morbidity with length of herd life. The estimated hazard rate ratios for leaving the milking herd and 95% confidence intervals for dullness, respiratory disease, and scours within 90 days of birth were 1.3 (0.9, 1.9), 0.9 (0.6, 1.3), and 1.0 (0.8, 1.3), respectively. Dullness was the only disease category with an estimated hazard rate ratio greater than 1, and although it was not statistically significant, may warrant evaluation in future studies of long term effects of calfhood morbidity.     

Early Adaptive Radiation of Birds: Evidence from Fossils from Northeastern China

Late Jurassic and Early Cretaceous birds from northeastern China, including many complete skeletons of Confuciusornis, provide evidence for a fundamental dichotomy in the class Aves that may antedate the temporal occurrence of the Late Jurassic Archaeopteryx. The abundance of Confuciusornis may provide evidence of avian social behavior. Jurassic skeletal remains of an ornithurine bird lend further support to the idea of an early separation of the line that gave rise to modern birds. Chaoyangia, an ornithurine bird from the Early Cretaceous of China, has premaxillary teeth.     

Spatial Response of Mammals to Late Quaternary Environmental Fluctuations

Analyses of fossil mammal faunas from 2945 localities in the United States demonstrate that the geographic ranges of individual species shifted at different times, in different directions, and at different rates in response to late Quaternary environmental fluctuations. The geographic pattern of faunal provinces was similar for the late Pleistocene and late Holocene, but differing environmental gradients resulted in dissimilar species composition for these biogeographic regions. Modern community patterns emerged only in the last few thousand years, and many late Pleistocene communities do not have modern analogs. Faunal heterogeneity was greater in the late Pleistocene.