24 research outputs found
Factors affecting pregnancy rates and calving difficulty in commercial beef heifers
Data from yearling Angus and Angus
crossbred beef heifers from a commercial
ranch were used to identify factors affecting
pregnancy rates (n=342) and calving difficulty
(n=295). Production data analyzed included
prebreeding weight, average daily gain during
the breeding season, and postbreeding weight;
evaluations of hip height, frame score,
weight:height ratio, and reproductive tract
score were made at approximately 1 yr of age.
Pregnancy rates were affected significantly by
weight:height ratio, prebreeding weight, and
reproductive tract score. However, based on
correlation coefficients, the magnitude of
influence of these traits on first-service
conception and overall pregnancy rates was
low. Calving difficulty in the same heifers
(n=295) was influenced significantly by calf
birth weight, heifer yearling frame score, and
average daily gain of the heifer during the
breeding season. Heavier calf birth weight
increased calving difficulty, whereas increases
in frame score and average daily gain reduced
calving difficulty
Factors influencing first-service conception and overall pregnancy rates in commercial beef heifers
Commercial beef heifers (n=1863) from
16 different sources were used to evaluate
the influence of management practices and
biological traits on first-service conception
and overall pregnancy rates. Frame score,
initial weight, overall ADG, body condition
score, reproductive tract score, source, AI
technician, and AI sire significantly influenced
first-service conception. Overall pregnancy
rates were influenced by frame score, body
weight, and ADG
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Laboratory Data for X-Ray Astronomy
Laboratory facilities have made great strides in producing large sets of reliable data for X-ray astronomy, which include ionization and recombination cross sections needed for charge balance calculations as well as the atomic data needed for interpreting X-ray line formation. We discuss data from the new generation sources and pay special attention to the LLNL electron beam ion trap experiment, which is unique in it's ability to provide direct laboratory access to spectral data under precisely controlled conditions that simulate those found in many astrophysical plasmas. Examples of spectral data obtained in the 1-160 A wavelength range are given illustrating the type of laboratory X-ray data produced in support of such missions as Chandra, XMM, ASCA and EUVE