Effects of zeranol on in vitro growth hormone release by lamb and rat pituitary cells.

A series of experiments was conducted to evaluate the effect of zeranol on release and synthesis of growth hormone (GH) by anterior pituitary cells established in either static or continuous flow cultures. Young adult male rats, slaughter-age lambs and juvenile lambs were used as sources of pituitary cells. In static primary cell cultures, no consistent effect of zeranol at 10(-7), 10(-9) or 10(-11) M was demonstrated by either rat or ovine cells.

Use of a standard forage to reduce effects of animal variation on estimates of mean voluntary intake.

Sixty test forages (alfalfa, timothy, bromegrass, and orchardgrass mixtures), of differing cuttings and maturities, were harvested as hay in each of 2 yr (30/yr) from three locations. Each of the 60 hays was chopped and fed to four growing sheep to determine voluntary intake. The duration of the trial was 2 yr with five experimental periods per year.

Effects of feeding, fasting and refeeding on growth hormone and insulin in obese pigs.

This study has indicated that temporal patterns of plasma GH changes were similar in lean and obese pigs with one to two secretory spikes occurring during a 6-hour period. Fasting caused increased GH in both pig strains; however, obese pigs, compared to lean, had lower GH during feeding and fasting. This depressed plasma GH of obese pigs may not be due entirely to impaired pituitary function since refeeding caused increased GH to levels similar to lean pigs.

Prediction of sheep responses by near infrared reflectance spectroscopy.

Prediction of animal response from near infrared reflectance spectra of feeds was compared with predictions from chemical analyses. Sixty samples of pure and mixed forage-based diets were obtained from sheep intake and digestion trials. Sheep responses measured were digestible energy, dry matter intake, and calculated intake of digestible energy.

Fetuses of lean and obese swine in late gestation: body composition, plasma hormones and muscle development.

The development of obesity in porcine fetuses was investigated using a lean and obese strain of pigs at 80, 90, 100 and 110 d of gestation. In absolute terms, fetuses of obese gilts (FO) generally had lower carcass weight and contained less total protein, dry matter and ash than fetuses of lean gilts (FL). In relative terms (percentage of wet carcass weight) FO, compared with FL, generally had decreased percentages of water and increased percentages of protein and lipid.