Crossmatings were accomplished among three semi-closed lines within a population of pigs, for the purpose of investigating effects of crossbreeding on reproductive traits. Two of the lines were purebred (Berkshire and Yorkshire); the third line ("Composite") consisted of descendants from inter se matings among offspring of crosses of the Berkshire...
The relationships of serum T₄
(thyroxine) levels and liver
nicotinamide nucleotide coenzyme (NAD and NADP) levels with production
of traits of beef cattle were investigated at both weaning (182
kg) and following performance testing (363 kg). In addition, the value
of these parameters as selection criteria for improved performance
was...
An experiment was conducted to determine if selection from
standardized litters would be effective in separating lines of mice
selected for increased and decreased litter weight at 14 days of age,
and if response to selection on this maternally influenced trait could
be accurately predicted.
Data were collected on litter...
An investigation of the effects of exogenous gonadotropic
treatments on fertility of various genetic groups of ewe lambs were
run over a six-year period. Since hormonal treatments varied and
the experimental animals were different from one breeding season to
the next, each year comprised a separate study. Hormone treatment
included...
The present investigation with the chromosomes of Zea mays
was conducted to determine: (1) the effects of chelating agents on the
process of cytological exchange, and (2) the effects of chelating agents
on genetic recombination.
To ascertain the influence of chelating agents on cytological
exchange, four known heterozygolis paracentric inversion...
The relationship between x-ray induced chromosome aberrations
and x-ray induced embryonic abnormalities was studied. Golden
hamsters were irradiated during four stages of gestation: the blastocyst
stage, 4.5 days post-copulation; the primitive streak stage, 6.5
days post-copulation; the organogenesis stage, 9.5 days post-copulation;
and the period of fetal growth, 11.5 days...
Electrocardiograms from 12 compressed male (CM), 16 compressed
female (CF), ten synthetic compressed female (SCF), nine
brachycephalic female (BF), and 15 dolichocephalic female (DF)
dwarfs from Davis, California, taken in the scapular lead S-II (prescapular
position positive and right forelimb negative) were analyzed,
The data on dwarf electrocardiograms were compared...
The investigations were based on a complete diallel cross
among three inbred lines of Hereford cattle. Records of Angus calves
born during the same period were used to obtain more accurate
estimates of environmental effects and to determine breed differences
among the various traits included in the study. Estimates of...
The effects of x-irradiation on quantitative genetic traits was
investigated by comparing the response of irradiated mice to selection
for litter size and 28-day weight with the response to selection
for the same two traits in non-irradiated lines. Irradiated lines
were maintained at three levels of x-irradiation, 25 r, 50...