Life Sciences Commons^™

The Effect Of Seasonal Cattle Grazing On California Bighorn Sheep Habitat Use, Melanie J. Steinkamp

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The effect of seasonal cattle grazing on a newly reintroduced population of California bighorn sheep (Ovis canadensis californiana) in Big Cottonwood Canyon, Idaho, was studied. The hypothesis that bighorn sheep avoid cattle was tested. The issue of avoidance between bighorn sheep and livestock is arguable. Some studies have found that bighorn sheep avoid cattle while others have found no response of bighorn sheep to cattle.

Evidence was found to document the avoidance of cattle by bighorn sheep. The size of the bighorn's home range and core area decreased with the movement of cattle into areas of high bighorn …

Twinning In Cattle: 111. Effects Of Twinning On Dystocia, Reproductive Traits, Calf Survival, Calf Growth And Cow Productivity, K. E. Gregory, S. E. Echternkamp, G. E. Dickerson, Larry V. Cundiff, R. M. Koch, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

An evaluation of natural twinning in beef cattle revealed that cows birthing twins had shorter (P < .0l) gestation lengths, more (P < .0l) retained placentas, more (P < .01) dystocia, more (P < .0l) days to estrus, lower (P < .0l) conception rates and more (P < .01) days to pregnancy than cows birthing singles. Days to estrus, conception rate and days to pregnancy were not affected by number of calves reared (1 vs 2) in cows birthing twins. Survival at birth was greater (P < .0l) for single- than for twin-born calves, but twins and singles did not differ (P > .05) in postnatal survival. When dystocia was experienced, calf survival at birth was 95% vs 73% for singles vs twins compared with 99% vs 92% when no dystocia was experienced. Calves born twins were lighter (P < .01) at birth, 100 d and 200 d, but twins and singles did not differ in postweaning gains. Total calf weights at 100 d per cow calving were 12% greater (P < .01) in cows birthing twins vs singles when twin calves reared by foster dams were! excluded. The potential increase in cow productivity for total calf weight at 100 d is 40% if calf survival rates of twins with dystocia relative to survival rates of twins without dystocia were comparable to survival rates of singles with and without dystocia, and if cows birthing twins were fed and managed to obtain conception rates equal to those of cows birthing singles. Identification of cows gestating twins to provide for their higher prepartum nutritive requirements and calving assistance at parturition is necessary to make twinning in cattle an economically viable technology.

Growth Stimulants And Feed Additives, Norris J. Stenquist

All Archived Publications

In recent years, the most revolutionary increases in beef cattle weights and feeding efficiencies have resulted from the development and use of growth stimulants, feed additives, and antibiotics. These nonnutritive products not only improve the rate and efficiency of gain but prevent certain diseases as well. Their use has significantly improved beef cattle production efficiency and provided a greater return per dollar invested than any other factor in the livestock industry. Growth stimulants deposit increased protein in the animal without changing protein or energy intake. They are designed to provide a constant slow release of active ingredients into the animal's …

Twinning In Cattle: Ii. Genetic And Environmental Effects On Ovulation Rate In Puberal Heifers And Postpartum Cows And The Effects Of Ovulation Rate On Embryonic Survival, S.E. Echternkamp, K. E. Gregory, G. E. Dickerson, Larry V. Cundiff, R. M. Koch, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

The potential of ovulation rate before 18 to 21 mo of age in puberal heifers as an indirect selection criterion for twinning rate was considered. Heritability (h²) was .07 ± .03 for single observations and .34 ± .18 for the mean of 7.9 estrous cycles per heifer. Estimated repeatability (r) of ovulation rate was ≤h², indicating negligible permanent environmental effects. Expected h² for mean ovulation rate (assuming h² = r = .07 for single observations) for increasing numbers of estrous cycles would be as follows: 4, .23; 6, .31; 8, .38; and 10, .43. …

Twinning In Cattle: 1. Foundation Animals And Genetic And Environmental Effects On Winning Rate, K. E. Gregory, S. E. Echternkamp, G. E. Dickerson, Larry V. Cundiff, R. M. Koch, L. Dale Van Vleck

Department of Animal Science: Faculty Publications

Foundation cows were selected using prior records from one of two sources, private herds or other projects at the Research Center. Comparing twinning rates before and after selection, the repeatability was lower for those from the fist (.08) than for those from the second (.16) source with a combined value of .12. Realized heritability of single-parity twinning rate estimated from selection of parents and response in daughters of foundation females was .06. Paternal half-sib estimate of heritability of twinning rate was .02 ± .07. Estimates of repeatability computed from calving records of females born in the project indicate that permanent …