Life Sciences Commons^™

Index Selection For Components Of Litter Size In Swine: Response To Five Generations Of Selection, S. M. Neal, R. K. Johnson, R. J. Kittock

Department of Animal Science: Faculty Publications

Selection for an index of ovulation rate (OR) and embryo (fetal) survival rate (ES) to 50 d of gestation (I = 10.6 x OR + 72.6 x ES) was practiced for five generations in a line that was a composite population of the Large White and Landrace breeds of swine. A control line sampled from the same population was selected randomly and mated. Ovulation rate and number of fetuses (FETS) were measured by laparotomy and ES was calculated as FETS/OR. The select line averaged 43 litters by 18 sires and the control line averaged 42 litters by 15 sires per …

The Water Vapor Conductance Of Squamate Reptilian Eggs: The Influence Of Scaling On Nesting Ecology., Louis A. Somma

Papers in Herpetology

Flexible-shelled eggs of squamate reptiles are strongly influenced by their surrounding microclimate, particularly the hydric conditions of the nest. The eggshell water vapor conductance of an egg can be an indication of its requirement for water from the nest. Ackerman et al. (1985. Physiol. Zool. 58:129-137) have described the scaling relationship for eggshell water vapor conductance (G_H2O) of flexible-shelled reptilian eggs (G_H2O = 981.8M^0.52). This scaling relationship was investigated with water vapor conductance data obtained from 8 species of lizards representing the families Iguanidae (Anolis carolinensis, A. sagrai, Sceloporus woodi, S. virgatus) …

Factors Limiting Sexual Reproduction In Platanus Wrightii In Southeastern Arizona, Jane H. Bock, Carl E. Bock

Aliso: A Journal of Systematic and Floristic Botany

Arizona sycamore (Platanus wrightii: Platanaceae) is a riparian tree of the southwestern United States and adjacent Mexico. It is failing to reproduce in certain canyons where mature, seed-producing trees of this species occur. Three hypotheses were tested to explain this reproductive failure: I) the presence of domestic cattle prevents reproduction, 2) seeds produced in certain canyons are inviable, and 3) annual flash floods destroy seedlings and young saplings but not the large, mature trees.

Canyons, either grazed or ungrazed by domestic animals, were surveyed for the presence of seedlings and young trees. In the laboratory, seeds were tested …

G89-926 Swine Reproductive Problems: Infectious Causes, Alex Hogg, Donald G. Levis

University of Nebraska-Lincoln Extension: Historical Materials

This NebGuide describes causes, clinical signs, control, prevention and treatment of swine reproductive problems due to infectious diseases. The reproductive potential for the ideal sow has been calculated as 31.2 pigs weaned per year. The United States average is 14 pigs per sow per year--less than one-half the reproductive potential of the ideal sow. A major part of this low reproductive efficiency is due to either infectious or non-infectious causes. The infectious causes of swine reproductive problems are addressed here.

G89-989 How To Interpret The New Animal Model For Dairy Sire Evaluation, Jeffrey F. Keown

University of Nebraska-Lincoln Extension: Historical Materials

In question and answer format this NebGuide addresses changes in genetic evaluations of both dairy cows and sores.

Why is the United States Department of Agriculture (USDA) changing the dairy sire and cow evaluation system?

The answer is simple. The Animal Model for genetic evaluations is more accurate than the old Modified Contemporary Comparison Method (M.C.C.). Previously the major limiting factors to implementing the Animal Model were computing costs and memory requirements. With the advent of new Super Computers, the computations are feasible on a national scale.

What is the Animal Model?

The Animal Model simultaneously evaluates cows and sires …