Two biological types of cows, straig htbred Herefords (HxH) and Simmental-Hereford cros ses (SxH), of similar body condition were individually fed over a 10 week period to compare the biological types for maintenance and to determine the influence of milk production potential and of size. Cows were nonlactating and in the last part of the first trimester of pregnancy. During the first 5 weeks of the feeding experiment, one-half of each type was fed 75% of est imated maintenance while the other half was fed 125% of estimated maintenance. During the last 5 weeks of the experiment those fed at 75% of maintenance in the first 5 weeks were now fed 140% of maintenance while those fed 125% of maintenance in the first 5 weeks were now fed 65% of maintenance. Maintenance requirement was estimated by two methods. The first method, regression of gain or loss on energy intake, showed a higher, but non-significant maintenance requirement for SxH (137.5 vs. 128.3 kcal ME/kg.75/day for SxH and HxH, respectively). The second method, which involved estimating maintenance as the residual when energy associated with gain or loss in weight was subtracted or added to the total energy intake, gave maintenance values of 117.6 and 145.9 kcal ME/kg.75/day for HxH and SxH cows, respectively. A comparison of gain in weight for amount of energy consumed, for cows having equal energy intake per unit of metabolic size, indicated that HxH cows used energy more efficiently than SxH cows (P<.20). The SxH cows were higher in milk production but when the effects of biological type were removed milk production potential was not significant. Size had a linear, negative effect upon maintenance requirement even though weight was expressed as wkg.75. When the .75 exponent was replaced by either .7, .73, or .78, size was still significant and negative.

This paper presents information obtained from 1972 and 1973 on the reproduction, survival and density of snowshoe hares (Lepus americanus) in Cache National Forest, Utah. The main objectives of the study were: (1) to estimate population densities; (2) to measure adult and juvenile mortality ; and (3) to measure natality rates , including recruitment (realized annual natality). Live-trapping and snaring were used to estimate population levels and to collect hares for necropsy. Fecal pellet counts were used to evaluate relative habitat use by hares. The results of this study were compared to other studies of snowshoe hare ecology in North America. Based on the density, survival and reproductive output observed, recommendations were made for the management of snowshoe hares in Utah.

Twenty-six range beef cattle ranches in southern Utah were surveyed by personal interview to obtain production data. The data were used to characterize the level of production efficiency in terms of calving rate, weaning rate, weaning weight, and net weaning weight in these operations; and to identify factors associated with differences in productivity. The data revealed that productive efficiency was generally lower than the potential. Mean calving rate of cows exposed for breeding was 83.4%. Stepwise regression involving calf death losses at or shortly after birth and heifer replacement rate accounted for 98.3% of the variance in calving rate. Calving rate differed (p< .05) with cow condition and herd type. Crossbred herds averaged the highest calving rate (90.3±6.3) compared to the straight bred herds (76.1±9 .9 ). Mean weaning rate was 80.1%. The difference of 3.2% between calving rate and weaning rate reflects pre-weaning death losses. Mean calving date, age of replacement heifer at first breeding and calving assistance influenced weaning rate but only for 31.5% of the total variance of weaning rate (p < .25). Crossbred herds had higher weaning rates (86.7±7.3) vs. straightbred herds (72.6±12.5). Also cows in moderate condition during lactation had higher weaning rates (83.0±10.2) compared to cows in borderline condition (76.2±12.9). An average weaning weight of 20 1.6 kgs was obtained by the herds surveyed. Weaning age (p < .05) herd size, (p < .175) and herd type (p < .25) were important source of variation in weaning weight. Mean net weaning weight of calves (pounds of calf weaned per cow exposed) was 178 kgs. Mean calving date and cow condition affected (p < .05) net weaning weights. Crossbred herds averaged net calf weaning weight 70.1 lbs higher than straightbred herds. Positive correlations (.18 < r < .32) were observed between cow condition, range condition, and calving rate, weaning rate, weaning weight and net weaning weight. Correlations between calving rate, weaning rate, length of breeding season, number of cows per bull and heifer replacement were negative (-.25 < r < -.08). A flowchart of a range beef cattle production system was conceptualized. The chart may be used to examine management alternatives.

The greater sage-grouse (Centrocercus urophasianus; sage-grouse) is a species of conservation concern that occupies sagebrush-dominated (Artemisia spp.) landscapes across the western United States and southern Canada. The U. S. Fish and Wildlife Service (USFWS) reviewed the status of the sage-grouse in September 2015 and determined that it did not warrant protection under the Endangered Species Act due to collaborative efforts between numerous public and private stakeholders. However, this decision hinged on federal and state commitments to continue science-based management of sagebrush habitats. As human development increases across the west, there is an increasing need for understanding the impacts of disturbance on sage-grouse. Filling this knowledge gap is important because it will allow us to predict how sage-grouse populations may respond to changes in the future. I assessed how two types of disturbance (wildfire and transmission line construction) influenced habitat use of a population of sage-grouse in southern Utah. I deployed Global Positioning System (GPS) transmitters on 26 (21 male and 5 female) sage-grouse in the Bald Hills Sage-Grouse Management Area in 2014 and 2015 to record what habitat sage-grouse were using during the summer and winter seasons. I compared these used locations to habitat that was seasonally available to the birds using resource selection functions. My models showed that in the summer, birds showed preference for areas burned and reclaimed within the last 10 years. I suggest that this may be occurring because the birds are seeking out vegetation that was seeded by the Bureau of Land Management (BLM) during wildfire reclamation. In the winter, my models showed an overall 3% decrease in predicted probability of use for winter habitat in the vicinity of the transmission line corridor, but this change did not immediately result in increased avoidance by sage-grouse when comparing spatial distributions for sage-grouse locations within winter habitat near the transmission line. I suggest that this is because the new transmission line was paired with a preexisting line which was already avoided by sage-grouse. However, the construction of the new line could have long-term consequences outside the two year scope of my study. These impacts could be delayed because sage-grouse are strongly tied to historic habitats and may not change habitat use immediately in spite of landscape changes. Additionally, the presence of the new line could cause indirect landscape changes which may only manifest over longer time periods such as increasing human activity in the area or changing the distribution of avian predators of sage-grouse that use the transmission line for perching. I recommend continued monitoring of sage-grouse in the area to determine if any changes in habitat use manifest in future years.

Experiments were conducted to determine the genetic reproductive potential of Rambouillet and St. Croix ewes . Ovulation rate (monthly) and estrus (daily) were observed for two years on 10 ewes of each breed to establish seasonal patterns . Both breeds demonstrated seasonal anestrus from May through July. Ovulation rates reached 2.0 or greater for both breeds during September to November, and decreased to 1.25 by March. Breeding groups for St. Croix and Rambouillet ewes were bred each February and August for five years to establish lambing performance at six month intervals. Age at first lambing was earlier for St. Croix than Rambouillet (89% vs 0.0% lambing at 12 months of age). Both breed and age influenced lambing rate. Fifty-two of 108 (48%) lambings from mature St. Croix ewes occurred at six month intervals, compared to 1 of 85 for Rambouillet ( 1.2%}. No Rambouillet under 36 months lambed at 6 month interval, while 8 of 61, 12 month St. Croix ewes lambed at a 6 month interval (13.1%). Mature St. Croix ewes that lambed at six month intervals produced 3.44 lambs per year, compared to 2.03 for ewes that lambed once a year. Parturition interval was 262 days for mature and 302 days for 24 month and younger St. Croix ewes on a six month lambing schedule. Parturition interval for mature Rambouillets was 355 days. Blood samples were taken twice weekly and serum progesterone measured by RIA in 17 St. Croix and four Rambouillet ewes that lambed during the normal breeding season, to determine occurrence of postpartum ovulation. Average days to first postpartum ovulation was 35.8 and 35.6 for St. Croix and Rambouillet, respectively. Thirteen of seven teen (76.5%) St. Croix ewes showed estrus with first ovulation, while none of the Rambouillet showed estrus with first or second postpartum ovulation. The shortened postpartum period for St. Croix compared to Rambouillet (40 .2 vs > 70 days) was a result of estrus accompanying the first or second postpartum ovulation.

Over the past decade, demand for recreation has increased as part of Alaska's doubling growth in tourism. Along the Chilkoot River, near Haines, fishing and bear viewing have become increasingly popular. I investigated the ecological and behavioral interactions there between two brown bears, salmon, and humans between 2000 and 2002. My objectives were to: (1) determine if specific human activities differentially influenced bear activity and foraging behavior, (2) identify temporal and spatial habitat use patterns, (3) evaluate brown bear response to natural and human disturbances and quantify related flight distances, (4) investigate changes in bear foraging behaviors in response to prey abundance and human activity to find if bears selectively forage to maximize energy intake, and (5) assess the role of individual tolerance for human proximity in relation to specific foraging behaviors. Evidence clearly indicated that temporal and spatial brown bear activity patterns were influenced by human activity. Bears were most active and spent the longest periods of time fishing when the numbers of anglers and vehicles were below threshold levels. Adult female bears disproportionately preferred (73%) non-roaded riparian habitat, while subadults were less selective. I classified over 1000 disturbance responses and found human activity accounted for 46% of bear departures with a mean flight response distance of 97 meters. When humans were either absent or at distances greater than or equal to 100 meters from bear activity, bears captured fish at higher rates, captured 2.65 times as many fish, and caught greater proportions of live fish (71%). The greatest predictors of capture rate were the time of day when bears fished, the proximity of human activity, and the individual's tolerance level. Bear tolerance for human proximity helped explain variation in capture rates, foraging bout lengths, and total salmon captured. This suggests nutritional rewards for bears adapting to human disturbance. These analyses depict clear relationships with simple interpretation of the dynamic relationships between people, bears, and their environment. With improved understanding of the Chilkoot River's natural resources, managers can work to reduce bear-human conflicts and plan for continued growth in tourism and recreation.

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No description available.

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Direct selection for increased litter size was practiced for eleven generations in a Large White-Landrace composite line of pigs. Litters were standardized at birth so that no replacement gilts were reared in a litter with more than ten pigs. A contemporary control line was maintained. In generation nine, the estimated mean breeding value for litter size was 0.63 pigs greater in the select than control line. The objective of this research project was to test associations between Type I markers and response to selection. A candidate gene approach was employed to search for markers, which may explain some of the difference in litter size between the two lines. Two novel markers were discovered within the follistatin gene, which have shown associations with litter traits. The estrogen receptor marker was not segregating in the population of pigs used in this study. The retinol binding protein marker was segregating in the population studied; however the magnitude of allele frequency change was relatively small. Polymorphisms were not detected in other candidates tested.