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At least 217 records · Page 12Linked to original sources
PubMed1985

Seasonal and circadian patterns of circulating prolactin during lactation and seasonal quiescence in the tammar, Macropus eugenii.

Prolactin was measured in peripheral plasma of female tammars once a week for 14 months and every 2 months it was measured in a subgroup of 7 tammars at hourly intervals for 28 h to determine short-term changes in concentration. During the course of the study 6 females gave birth in January/February and reared their young to weaning in October-November, while another 4 gave birth 1.5-3.0 months later and weaned their young in November-December. Concentrations of prolactin were less than 40 ng/ml in a non-lactating animal and for the first 140 days of lactation in the others. Between 140 and 180 days of lactation the concentrations of prolactin fluctuated between 10 and greater than 100 ng/ml and thereafter remained high until the young vacated the pouch for the last time at about 250 days. After pouch exit the concentrations declined to about 40 ng/ml even though lactation continued for a further 21-35 days. Although the short-term patterns of prolactin concentrations showed no consistent relationship between light-dark phases there was an increase in the magnitude and duration of peaks of plasma prolactin which correlated with the stage of lactation. Removal of pouch young aged between 203 and 242 days for 24 h resulted in a rapid decrease in plasma prolactin concentration which was reversed when the young was returned to the pouch, indicating that the high levels of prolactin in the second half of lactation may be maintained by the sucking stimulus of the pouch young. This period of lactation, therefore, may be equated with lactation in eutherians, but there appears to be no eutherian equivalent to early lactation in the tammar.

Animals↗
PubMed1988

Relationships between nutritive quality and fiber components of cool season and warm season forages: a retrospective study.

Feeding trials were conducted with 428 forages in three forage classes (C3 grasses, legumes, C4 grasses) fed ad libitum to sheep and with 170 forages fed to cattle over a 20-yr period. Of this total, 153 forages were fed concurrently to sheep and cattle. Where the same forages were fed, mean dry matter digestibility (DMD) and dry matter intake (DMI) were lower (P less than .01) for sheep than for cattle, with significant effects of forage class. With the main population of forages, the regression of DMI on DMD was positive and curvilinear (P less than .01) for sheep, with no effect of forage class, and positive and linear (P less than .0001) for cattle, with a significant effect of class. For all forages, correlations between DMI and neutral detergent fiber (NDF) concentration were -.57 for sheep and -.41 for cattle; regressions differed (P less than .05) with class and animal species. Correlations of DMD with NDF and acid detergent fiber (ADF) concentrations were -.45 and -.59 (P less than .01), respectively, for sheep, and -.32 and -.39 (P less than .01) for cattle; again, regressions differed significantly with class and animal species. Within forage class, regressions of DMD and DMI on fiber components generally were linear. Intake of NDF (NDFI) was related to NDF percentage for all forages by a quadratic regression, with significant differences due to animal species and forage class. Results indicate that relationships between DMD, DMI and fiber fractions differ between forage classes and animal species, that C4 grasses are consumed at levels higher than would be expected from their DMD and fiber concentrations and that ruminants increase NDFI in response to higher NDF concentrations in the forage.

Animal Feed↗
PubMed1992

A seasonal depression. Management of seasonal affective disorder.

1. SAD is a mood disorder characterised by recurring cyclic periods of autumn/winter dysthymia alternating with late spring/summer euthymia or hypomania. 2. It is now thought that SAD sufferers may be deficient in certain brain chemicals, and it is likely that the interactions of a number of neurotransmitters are responsible for the disorder. 3. In the UK, 72% of SAD sufferers report an increase in sleep from around seven hours in the summer to nine in winter. 4. Phototherapy has been proved an effective treatment for SAD, and lamps for phototherapy are becoming increasingly available.

Humans↗