Potential Value of Ultrasound to Sort Feeder Cattle into More Uniform Groups for Finishing and Marketing

Cattle in three experiments were scanned with ultrasound as feeders to measure ribeye area and thickness of fat cover to determine if cattle could be sorted into outcome groups with respect to carcass yield. Sorting the cattle into low fat cover or large ribeye groups resulted in improved carcass yield grades. There were no effects on carcass quality grades related to sorting of the cattle. Cattle with greater fat cover at the beginning of the feeding period were heavier, seemed to be more mature and had less muscle growth during the finishing period. There were no significant differences in gain among the groups, but cattle with more fat cover had poorer feed efficiency. Ultrasound seems to have potential to sort feeder cattle, but before it can be used in practice, growth curves need to be developed to predict final end points of individual cattle.

Investigation of the Potential Effects of Epizootic Hemorrhagic Disease Virus on Iowa Cattle

Epizootic hemorrhagic disease virus (EHDV), an arthropod-borne orbivirus, causes significant mortality in white-tailed deer and can also cause disease in cattle. Objectives of this preliminary investigation were 1) to survey cattle at auction markets to determine the prevalence of anti-EHDV antibodies in Iowa cattle, 2) to determine EHDV seroprevalence in herds in which clinical EHD had been diagnosed, and 3) to determine whether EHDV is associated with stillbirths and/or congenital anomalies in calves. There was a 15% seroprevalence in auction market cattle; positive cattle were from southern, central, and western Iowa. Herds in which clinical EHD had been diagnosed had >60% seroprevalence. Viremia was detected in both clinically affected and unaffected cattle during an EHD outbreak. EHDV exposure was not consistently associated with congenital anomalies. Although additional surveillance is warranted, EHDV is unlikely to have a significant effect on the reproductive health of Iowa cattle.