Theses and Dissertations at Montana State University (MSU)
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Item Genomic, microbial, and linear relationships between residual feed intake, dry matter intake, average daily gain, and post weaning weights in range sheep(Montana State University - Bozeman, College of Agriculture, 2023) Schaub, Daniel James; Chairperson, Graduate Committee: Christian J. PosberghOver forty years, United States sheep producers have selectively bred range sheep for larger post-weaning weights using estimated breeding values. However, this has led to increased feed intake, prompting this study's objective to quantify the relationship between lamb growth estimated breeding values, feed intake, and feed efficiency. The study involved 40 Targhee and 40 Rambouillet ewe lambs weaned at four months and put on a GrowsafeTM feeding system for a 56-day experimental period, with ewes weighed weekly and at the start and end of the trial. Residual feed intake was calculated using body weights, average daily gain, and daily feed intake measurements. The ewe lambs' post-weaning weight estimated breeding value was associated to their phenotypic traits. These procedures were repeated when the same ewes were yearlings and at maintenance. The study found that while post-weaning weight estimated breeding values predicted dry matter intake (P<0.05), they lacked association with residual feed intake (P>0.05) in both experimental periods. However, the ewe's post-weaning weight estimated breeding value predicted mid-trial body weight in both periods (P<0.05). Thus, while selecting higher post- weaning weight animals may increase feed usage due to larger body size, it does not affect feed efficiency. Comparing the residual feed intake between the two experimental periods, growth residual feed intake measurements did not predict residual feed intake in maintenance. Therefore, caution should be used when utilizing residual feed intake from the growth period as an indicator of feed efficiency in maintenance. The study also examined rumen microbial profiles in sheep between the two experimental periods. Methanogenic archaea were relatively increased within the growth experimental period, where a pelleted diet was used, and cellulolytic bacteria were increased in the maintenance experimental period, where hay was provided. Since methanogens are associated with decreased feed efficiency, diet may play a role in changing a sheep's microbiome towards more feed efficient bacteria. Finally, a genome-wide association study found the Dmrt2 gene associated with DMI and RFI in maintenance. The Dmrt2 gene may regulate muscle and bone development in the early embryo, affecting feed efficiency in sheep later in life.Item Clodronate use in yearling, exercising horses on endocrine regulation of bone growth and development(Montana State University - Bozeman, College of Agriculture, 2023) Conrad, Matthew Benjamin; Chairperson, Graduate Committee: Amanda N. BradberyExtra-label bisphosphonate use in juvenile horses is widespread despite limited scientific understanding of biological and welfare impacts on skeletally immature, exercising horses. The objective of this study was to determine the effects of clodronate on endocrine regulation of bone growth, hypothesizing there would be no effect. To test this, 32 Quarter Horses were stratified by age (500 + or - 13 d of age), BW (336 + or - 26 kg), sex (n = 16 males, n = 16 females), and initial bone optical density by aluminum equivalence into four treatment groups for a 168-d trial. The experimental period was divided into two phases mimicking sales preparation (Phase I: d 0-83) and early performance training (Phase II: d 84-168). Investigators were blinded, and all horses received iso-volumetric intramuscular injections of either 1.8 mg/kg BW clodronate disodium (OSPHOS®) or saline (placebo) on d 0, 42, 84, and 126. Treatments consisted of control (CON; n = 8), single-dose (1X; n = 8; d 84), two-dose (2X; n = 8; d 0, 84), and four-dose groups (4X; n = 8; d 0, 42, 84, 126). Physical measurements including BW, wither height (WH), hip height (HH), body length (BL), and heart girth (HG) circumference were recorded every 42 d from d 0. Serum samples were collected every 42 d prior to treatment administration to quantify growth hormone (GH), calcitonin (CT), parathyroid hormone (PTH), and ionized calcium. Data were analyzed using PROC MIXED of SAS. All physical growth parameters increased (P < or = 0.01) and growth hormone tended to decrease over time (P = 0.09) following normal growth patterns. A treatment time interaction was observed for PTH (P = 0.05) where concentrations increased on d 84 in 4X and on d 126 in 2x following the second administration of clodronate while 1X and CON remained unchanged. Ionized Ca decreased over time (P < 0.01) with no effect on CT concentrations (P > 0.33). These results suggest that while administration of bisphosphonate has no effect on growth morphometrics, its repetitive use alters PTH concentrations after two doses.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 Does calcium propionate elicit similar growth and reproductive responses as monensin in developing heifers?(Montana State University - Bozeman, College of Agriculture, 2017) Hubbard, Ashton Rose; Chairperson, Graduate Committee: Rachel L. Endecott; C. C. Reichhardt, A. R. Williams, I. R. McGregor, C. M. Page, D. M. Staudenmeyer and R. L. Endecott were co-authors of the article, 'Does calcium propionate elicit similar feed efficiency and reproductive responses as monensin in developing heifers?' submitted to the journal 'Journal of animal science' which is contained within this thesis.Replacement beef heifer development is critical for the continued production of beef and for ranch success. Objectives of this research were to investigate the growth and reproductive responses of developing heifers fed similar basal diets supplemented with pellets containing different feed additives. Pellet treatments consisted of 2.27 kg x heifer -1 x d -1 of: 1) control with no feed-additive (CON), 2) 200 mg x heifer -1 x d -1 monensin (MON), or 3) 40 g x heifer -1 x d -1 calcium propionate (PRO). Experiment 1 utilized one hundred and ninety-eight heifers (254 + or = 3.8 kg) stratified by BW and randomly assigned to one of six pens (n = 2 pens per treatment). Experiment 2 utilized fifty-eight heifers (304 + or = 3.4 kg) stratified by BW and randomly assigned to one of 12 pens (4 pens per treatment). Heifers were fed a grass hay basal diet in both experiments (Exp. 1: 65% TDN and 11% CP; Exp. 2: 62% TDN and 15% CP, DM basis). Experiment 1 was 129 d and Experiment 2 was 122 d. Body weights were collected at the beginning and end of each experiment, with interim BW collected every 30 d. Serum samples were collected via coccygeal venipuncture and analyzed for progesterone to determine pubertal status. Overall pregnancy rates and pregnancy rate from AI were determined. Experiment 1 observed no differences for initial BW, final BW, overall ADG, pregnancy rate from AI, or overall pregnancy rate (P > or = 0.16). Fewer CON and PRO heifers were pubertal at experiment start than MON heifers (P < or = 0.01) in Experiment 1, which was unexpected. Differences in puberty achievement were diminished at the end of the experiment. Experiment 2 observed no differences for initial BW, final BW, overall ADG, pregnancy rate from AI, or overall pregnancy rate (P > or = 0.19). Treatment had no effect on puberty achievement at beginning or end of experiment (P > or = 0.09). A period effect was observed for ADG in both experiments (P < or = 0.01) which may be related to cold stress. Neither calcium propionate nor monensin resulted in improved performance compared to no feed additive. Further research is warranted to elucidate the impact of calcium propionate on heifer development.Item Influence of supplementation on the productivity of ewes grazing improved pasture and suckling twins(Montana State University - Bozeman, College of Agriculture, 1988) Frey, Ana LidiaItem The Evaluation of paternal half-sib heritabilities and genetic, environmental and phenotypic correlation estimates for randomly selected Hereford cattle(Montana State University - Bozeman, College of Agriculture, 1990) Veseth, Dale AllenItem Growth patterns of beef calves on western rangeland over discreet intervals in the grazing season(Montana State University - Bozeman, College of Agriculture, 1989) Church, Steven BennettItem Fecal output by calves of Tarentaise, Hereford and crossbred cows under range conditions(Montana State University - Bozeman, College of Agriculture, 1998) Miller, Eric ThomasItem Influence of different forms of methionine on gain, intake, and ruminal parameters of heifers grazing improved pastures(Montana State University - Bozeman, College of Agriculture, 1991) Sorensen, Sharon JoyceItem Effect of growth path on carcass composition and meat quality(Montana State University - Bozeman, College of Agriculture, 2013) Perz, Katharine Anna; Chairperson, Graduate Committee: Jane A. Boles.Reducing variation in tenderness is a goal for the meat industry. The objective of this study was to determine if different growth patterns, not caused by nutrient restriction, impacted carcass characteristics and tenderness. Simmental x Angus steers (n = 18) reared under similar conditions, fed in the same pen at the feedlot, were allocated into fast (n = 9) and slow (n = 9) growing groups based upon four sets of weight data. After slaughter, carcass data were obtained. The striploin was removed, cut into steaks, and aged for 1, 3, 7, 14, and 21 days. For each aging period, one steak per steer underwent evaluation of shear force and MFI. Myofibrils were isolated from aged muscle samples and protein degradation was visualized with the use of SDS-PAGE. Carcass weight (P< 0.0001) and LD area (P = 0.0093) were significantly affected by growth rate. Shear force (P = 0.0003) and MFI (P< 0.0001) were significantly affected by length of aging, but not by growth rate (P> or = 0.3184); nor was there a significant interaction between growth rate and length of aging (P> or = 0.6555). Even though the shear force x growth rate finding was not statistically significant, shear force of steaks from fast-growing animals had a greater reduction in shear force values indicating a difference in early tenderization. A currently unidentified protein with a molecular weight between 130 and 100kDa was seen earlier postmortem in more tender muscle. This degradation was more apparent in muscle from fast growing steers. A 30kDa component also appeared earlier, and at a greater band intensity, in more tender muscle. Degradation of the 30kDa component was also more evident in fast growing steers. These results suggest that there is a difference in protein degradation in muscle from animals with differing growth paths. The results of this study suggest that more research is warranted to identify differences in protein degradation due to growth rate and to elucidate the effect of growth rate on variation in tenderness.