Three sigmoidal growth equations were tested for their usefulness in fitting mammalian growth curves. The von Bertalanffy, Gompertz, and logistic equations were fitted to growth data by nonlinear regression techniques. The residual sum of squares and deviations of predicted neonate, weaning, and adult masses from observed values were used as criteria to choose among the models. The von Bertalanffy equation provided the smallest residual sum of squares, while the Gompertz equation fitted equally well by this criterion. The logistic equation overestimated neonate mass and underestimated adult mass, the Gompertz overestimated neonate mass, and the von Bertalanffy overestimated weaning mass. The Gompertz model was chosen to fit a sample of 331 species; growth rate constants, K , for these species are presented. The relationship of K to adult mass was calculated and was found to have a slope similar to that of altricial birds. K -values were found to be comparable to those reported by Case (1978) and consistently higher than those of Millar (1977). Species having differing rates from those reported by Case or Millar were also identified; ground squirrels had faster growth rates and seals had slower growth rates when rate of growth was estimated by the Gompertz equation.

Fitting Sigmoidal Equations to Mammalian Growth Curves

High-fat feeding during pregnancy and lactation affects offspring metabolism in rats

An animal's nutritional status depends on (1) nutrient accessibility, (2) nutrient demand, and (3) physiological, metabolic, morphological, and behavioral compensations that avert or minimize discrepancies, if any, between the first two. The main thesis of this essay is that the diversity and potency of such compensatory mechanisms have often been underrated, and hence the frequency and intensity of nutritional stress in free-living animals have often been exaggerated. This theme is explored in conjunction with an inventory of the modes of compensation for actual or potential dietary deficiencies.

Periods of Nutritional Stress in the Annual Cycles of Endotherms: Fact or Fiction?

Highlight: Protein and energy requirements of deer and supplies of these nutrients in native forage are synthesized into a model to estimate carrying capacity of seasonal ranges of a migratory mule deer population in north central Colorado. The model indicates that summer forage will support many times the number of deer present, but winter forage will not sustain deer at any population level. Instead, duration and severity of winter determine the length of time deer can survive on these ranges. Habitat evaluation based on quantification of nutrient supplies and their availability offers a more logical alternative for evaluating deer winter ranges than traditional methods based on measurements of twig lengths of so-called "key" species.

/pdf/evaluation-of-deer-habitat-on-a-nutritional-basis-72u8s0ktuo.pdf

Evaluation of deer habitat on a nutritional basis.

Good-genes hypotheses predict that development of secondary sexual characters can be an honest adver- tisement of heritable male quality. We explored this hypothesis using a cervid model (adult, male white-tailed deer, Odocoileus virginianus) to determine whether antler development could provide an honest signal of a male's genetic quality and condition to adversaries. We compared antler, morphometric, hormonal, and parasitic data collected from hunter-harvested deer to characteristics of the Mhc-DRB (Odvi),the most widely studied gene of the major histocom- patibility complex (MHC) in Artiodactyla. We detected associations between genetic characteristics at Odvi-DRBand antler development and body mass, suggesting that antler development and body mass may be associated with pathogen resistance in deer and thus may be an honest signal of genetic quality. We also detected associations between Odvi- DRB characteristics and serum testosterone during the breeding season, suggesting that certain MHC characteristics may help deer cope with stresses related to breeding activity. In addition, we observed a negative relationship between degree of antler development and overall abundance of abomasal helminths. Our observations provide support for the hypothesis that antler development in white-tailed deer is an honest signal of quality.

http://wp.auburn.edu/deerlab/wp-content/uploads/2014/05/462001-Evolution.pdf

Major-histocompatibility-complex-associated variation in secondary sexual traits of white-tailed deer (Odocoileus virginianus): evidence for good-genes advertisement.

R. H. Ingram

Papers

Nutrient requirements for growth and antler development in the white-tailed deer'

The influence of dietary fat and carbohydrate on growth and longevity in rats.

The influence of dietary fat and carbohydrate on reproduction and lactation in rats.

The Effect of High Levels of Terramycin and Streptomycin on Longevity in the Rat

A technique for obtaining samples of mast