Theses and Dissertations at Montana State University (MSU)
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Item Ewe undernutrition alters cotyledon development and function(Montana State University - Bozeman, College of Agriculture, 2023) Welter, Francesca Marie; Chairperson, Graduate Committee: Sarah R. McCoskiUndernutrition is common for animals maintained on rangelands, particularly during periods of drought. Undernutrition during gestation can be detrimental to offspring development. The placenta is a known mediator for maternal-fetal nutrient exchange, and developmental impacts to the placenta during nutritional stress contribute to poor offspring outcomes. The objective of this study was to determine the impacts of maternal nutrient restriction on the development and function of placental cotyledons. Targhee ewes were allocated into two dietary treatment groups for the entirety of gestation. The control group (CON; n = 10) was fed to meet 100% of NRC requirements and the nutrient restricted group (NR; n = 11) was fed to meet 60% of NRC requirements, to mimic the nutritional stress experienced by range ewes during drought. At the time of lambing total placental weight, total cotyledon number, and lamb birth weight was recorded. Cotyledons (n = 3 / placenta) were removed from multiple locations, weighed, and processed for RNA-sequencing. Total placental weight, total cotyledon number, and lamb birth weight were not affected by maternal diet restriction (P > 0.05). Average cotyledon weight was greater in the CON group compared to the NR group (P < 0.05). Gene ontology (GO) and Kyoto encyclopedia of genes and genomes pathways (KEGG) analyses were performed to identify biological pathways involved in placental function and nutrient transfer. Cotyledons from NR singletons vs CON singletons expressed 470 differentially expressed genes (DEGs; P < 0.05; 187 up-regulated, 283 down-regulated). Gene ontology terms represented by DEGs include hormone activity (P = 0.0003) and antigen processing and presentation (P = 0.0004 ). KEGG pathways of interest include pyruvate metabolism, estrogen signaling, extracellular matrix receptor interaction, and antigen processing and presentation. There were also 426 DEGs (P < 0.05; 195 up-regulated, 231 down-regulated) in cotyledons of NR twins vs CON twins. Represented GO categories include heme binding (P = 0.003) and oxidoreductase activity (P = 0.03). These data show that prolonged nutrient restriction alters cotyledon development and gene expression indicating impacts to placental function. These changes in placental function likely mediate poor offspring developmental outcomes observed following gestational under nutrition.Item Serum mineral concentrations in weaned Montana ram lambs and effects of dietary zinc source and concentration on developing Targhee rams(Montana State University - Bozeman, College of Agriculture, 2017) Page, Chad McBride; Chairperson, Graduate Committee: Tom Murphy; T. W. Murphy, M. L. Van Emon, J. G. P. Bowman, S. A. Wyffels and W. C. Stewart were co-authors of the article, 'Survey of serum trace mineral concentration in weaned Montana ram lambs: implications for trace mineral supplementation in weaned rams' submitted to the journal 'Journal of animal science' which is contained within this thesis.; M. L. Van Emon, T. W. Murphy, C. K. Larson, J. G. Berardinelli, I. R. McGregor and W. C. Stewart were co-authors of the article, 'Effects of zinc source and dietary concentration on zinc status, growth performance, wool traits, and reproductive characteristics in developing rams' submitted to the journal 'Journal of animal science' which is contained within this thesis.Trace mineral deficiencies exist in livestock operations and can contribute to decreased productivity and profitability. The objective of the first study was to quantify serum trace mineral concentrations in weaned ram lambs, with particular emphasis on Se and Zn. Serum samples (n = 221) were collected from ram lambs at 21 ranches throughout Montana and analyzed for Co, Cu, Fe, Mn, Mo, Se, and Zn concentrations. Additionally, water samples were analyzed for pertinent characteristics. Of ranches surveyed, only 67% provided a complete mineral supplement. Sheep that were provided supplementary trace mineral had greater serum Se concentrations (P < 0.001). Based on serum trace mineral concentration reference ranges, the two most commonly deficient and marginally deficient minerals across Montana were Se (19 and 23.8% of ranches, respectively) and Zn (9.5 and 57.1%, respectively). Of ranches sampled, 40 and 35% of water samples exceeded excessive concentrations in Na and sulfates, respectively. This regional knowledge of serum trace mineral concentrations in a sample of ram lambs can provide information for ranches to evaluate current and future mineral supplementation needs, as well as aid the feed industry in designing formulations for mineral premixes. Based on these results, a second study was designed with the objective to evaluate the effects of dietary Zn source and concentration on serum Zn status, growth performance, wool traits, and reproductive characteristics of developing yearling rams. Forty-four Targhee rams were used in an 84-d completely randomized design and were fed one of three pelleted dietary treatments: 1) a control diet without fortified Zn; 2) a diet fortified with a Zn amino acid complex (ZnAA); and 3) a diet fortified with ZnSO4. Serum samples were collected from each ram at four time periods to quantify serum Zn and testosterone concentrations. ZnSO4 had greater (P < or = 0.03) serum Zn concentrations compared to other treatments. Rams consuming ZnAA had greater (P < or = 0.03) average daily gain than rams in the other treatments. Wool regrowth was greater (P < 0.001) in the ZnSO4 treatment group compared to control. These results indicate that source and concentration of a Zn supplement appears to affect ram development.Item A study on some aspects of lifetime production in Targhee and Columbia sheep(Montana State University - Bozeman, College of Agriculture, 1970) Basuthakur, A. K.The relative lifetime lamb and wool production data for Targhee and Columbia sheep maintained by the Agricultural Experiment Station at Montana State University was analyzed for ewes born from 1950 to 1962. The productive traits concerned were analyzed by least square analysis of variance with interaction, phenotypic correlation and heritability was estimated. The total number of animals studied was 732 Targhees and 411 Columbias. In Targhees, it was observed that type of birth of the ewes sire affects the number of lambs born, whereas in Columbias the type of birth of ewe affects the trait. The interaction of type of birth was observed to be significant for number of lambs weaned in Targhees. The fleece production showed a significant effect of type of birth of ewe and her sire in Targhees but not in Columbias. Multiple births showed a positive significant correlation in Targhees with type of birth of the ewes sire whereas in Columbias type of birth of ewe was significant. Lamb and wool production showed variable significant correlations with yearling and weaning weights in both the breeds but were of low magnitude. The heritability for weaning and yearling weight were observed to be quite high in both the breeds in comparison tp other traits studied. The heritability of multiple births in Targhees was observed to be quite high compared to other breeds of sheep.Item Factors affecting survival of range sheep in the U.S. and characterization of sheep in Indonesia(Montana State University - Bozeman, College of Agriculture, 1984) SubandriyoItem Genetic analysis of growth and its relationship with lifetime production in Rambouillet, Targhee and Columbia ewes under range conditions of Montana(Montana State University - Bozeman, College of Letters & Science, 1986) Chavez, Juan FranciscoGrowth characteristics of sheep from birth to maturity and the evaluation of the genetic and phenotypic relationships between growth traits with lifetime lamb and wool production were studied using data from 302 Rambouillet, 338 Targhee and 175 Columbia ewes born between I960 and 1976. The Brody (1945) growth model was used for the derivation of growth parameters mature weight (A) and maturing rate (k). The Fitzhugh and Taylor (1971) equation-free model was used for the estimation of growth statistics; Absolute Growth Rate (AGR), Relative Growth Rate (RGR) and Absolute Maturing rate (AMR) for five intervals from birth to 18 mo. Genetic and phenotypic parameters were estimated by half-sib intraclass correlation using Harvey (1977) least-squares method for each breed and for the pooled data. Targhees were superior to Rambouillet and Columbias for weight of lamb at weaning (ATWW) and efficiency index (El). ATWW was the lifetime yearly average of kg of lamb weaned and El was ATWW per unit of ewes mature weight (A). Columbias were superior for yearly average grease wool produced (ATFP). Age at maturity was estimated on 39 mo, 38 mo and 41 mo for Rambouillets, Targhees and Columbias, respectively. Columbias had the highest A and the smallest k, Targhees matured the fastest. Ewes born twins had the highest El. From the pooled data, heritability estimates of average total of lambs born (ATLB), average total of lambs weaned (ATLW), average total weight of lambs weaned (ATWW), average total grease fleece produced (ATFP) and El were .43±.15, .33±..15, .11±>15, 68±..16 and .15±,15, respectively. Genetic correlation, between ATWW and A, indicated that ewes with high additive genetic potential for ATWW will have high genetic potential for larger A. The genetic correlation between ATWW and k was zero. For the three Fitzhugh and Taylor (1971) growth statistics, highest heritabilities were obtained for the weaning-12 mo interval: AGR2 (.80+.16), RGR2 (.76+.16) and AMR2 (.81+.16). RGR2 had the highest positive genetic correlations with ATWW (.95+.81), El (.77+.S2) and ATFP (.39+.19) among growth statistics. Inclusion of AGR2 and RGR2 in the construction of selection indexes would improve accuracy of selection for ATWW, ATFP and El. However, the contributions of A and k were inferior to AGR2 and RGR2. The use of any of the growth traits studied in selection indexes for improvement of ATFP and El simultaneously gave no advantage in improving efficiency of selection.Item Production of two-year-old ewes(Montana State University - Bozeman, College of Agriculture, 1957) Colman, Kenneth L.; Chairperson, Graduate Committee: J. L. Van HornThe purpose of the investigation of these data was to explore the possibilities of relationships existing between the body weights of the ewes during their early life and their subsequent lamb and wool production as two-year-olds. The effects of environmental influences, such as type of birth and age at weaning, on the growth of ewe lambs and their production as two-year-olds were studied. The growth of two-hundred and fifty-nine ewes was measured by body weights taken at irregular intervals from birth to twenty-three months of age. Records of the individual lamb and wool production of these ewes were tabulated with the body weights. Results showed that the effect of type of birth and age at weaning, on body weights of ewe lambs was reduced as the lambs progressed toward maturity from weanling age. It was also found that the birth weights, weaning weights, and fall yearling weights of the ewes were significantly related. The fall yearling weight of the ewes was most indicative of two-year-old lamb and wool production. A significant relationship was found between the birth weights of the Rambouillet ewes and the pounds of lamb born per ewe as two-year-olds. The relationship between the birth weights of the Targhee ewes and the pounds of lamb born per ewe was not significant nor was this relationship significant for the birth weights of the Columbia ewes and the pounds of lamb born per ewe. The early single-born lambs were consistently lighter at birth than the late single-born lambs; however, at weaning time, the early single-born lambs were consistently heavier than the late single-born lambs. The average daily gain of the early single-born lambs and the late single-born lambs was about the same. The weaning weights of the ewes and their yearling fleece weights were significantly and positively related. The difference between the yearling fleece weights of the ewes and their two-year-old fleece weights was significant, the yearling fleece weights being the heaviest. It is evident from this study that valuable genetic breeding stock may be lost if suitable precautions are not taken to adjust for environmental conditions affecting the size of ewe lambs at weaning time when most replacements are selected. According to these data and that published previously by other workers, a sounder method of selecting higher producing replacements is to retain a larger number of ewe lambs at weaning and to make final selections at fall yearling age. Since production factors are closely related to body weight at fall yearling age, the heavier ewes of similar breeding will be better producers than the lighter ewes if selections are made at this age.