Master of Science / Department of Animal Sciences and Industry / Teresa L. Douthit / Supplementation of lipids in the form of triglycerides is a safe method for increasing energy density in equine diets; however the effects of calcium salts of fatty acids (CSFA) on nutrient digestibilities in the horse are unknown. Eight cecally cannulated Quarter Horses were utilized in a crossover design in which horses consumed 1.5% BW smooth bromegrass hay and 0.5% BW concentrate supplemented with 4.1% soybean oil (SB) or 4.9% Enertia s/f® (E), a proprietary CSFA, for 28 d. Feces were collected for determination of apparent total tract digestibility of nutrients, and cecal digesta was evaluated for pH and concentrations of VFA and LCFA. Serum was collected following a 16-h fast and analyzed for triglycerides and cholesterol. Apparent total tract digestibilities of DM, NDF, ADF, CP, ether extract, and GE were unaffected by lipid source (P > 0.10). Serum triglycerides tended to be greater in horses consuming E compared to SB (P = 0.10); but, serum cholesterol concentrations were not different (P = 0.45). Cecal pH was unaffected by lipid source. Cecal concentration of total VFA tended to be greater in horses consuming SB compared to E at 2-h post feeding (P = 0.07). Cecal propionate concentrations were greater at 2-h post feeding for horses fed SB compared to horses fed E (P = 0.03). A treatment × time interaction was detected for total cecal LCFA concentration in which total cecal LCFA were greater in horses consuming E compared to SB at 2-h following consumption of a meal but became more similar as time progressed (P < 0.01). Secondly, an in vitro study was conducted to determine the effect of Co chloride on fermentation parameters using an equine cecal fluid inoculum in a 2 × 5 factorial arrangement of treatments. Alfalfa or smooth bromegrass hay (5 g DM) were utilized as substrates and were supplemented with 0.0, 0.5, 5.0, 25.0, or 50.0 mg Co/kg substrate DM. Cultures containing alfalfa had greater IVDMD compared to those with smooth bromegrass hay (P < 0.01). There was a forage × Co interaction in which gas production increased with time and was greater in cultures containing alfalfa (P < 0.01). Production of acetate, propionate, butyrate, isobutyrate, isovalerate, and total VFA, as well as acetate:propionate, were increased in cultures containing alfalfa compared to those containing brome hay (P < 0.05).

Utilizing local by-products can serve to significantly reduce the current feed costs for ruminant producers. The objective of this study is (1) to evaluate the effects of chemical and bacterial inoculants in combination with ensiling, on the nutritional value and ensiling compatibility of olive pomace (OP) and (2) to identify the most biologically favorable treatment and ensiling day of OP for feeding to cattle. Freshly centrifuged OP (Olivas de Oro Olive Company, Creston, CA) was treated with one of four treatments: (1) no additives (control; CONT); (2) urea applied at 5% of DM (UREA; Agrium U.S. Inc, Loveland, CO); (3) SiloSolve MC (SS; a mixture of Enterococcus faecium M74, Lactococcus lactis SR3.54, and Lactobacillus plantarum CH6072 applied at 1.5 x 105 cfu/g of fresh forage; Chr. Hansen A/S, Hørsholm, Denmark); (4) SiloSolve MC applied at the same rate as treatment 3 with calcium oxide (CAO; Flinn Scientific, Batavia, IL) applied at 5% of DM. Treated OP was ensiled in quintuplicates into 20-L laboratory silos with vents, which were sealed for 2, 10, 60, and 120 d in a completely randomized design. At 0 d, DM was 2 and 5% higher for UREA and CAO, respectively, while ash and pH were highest for CAO. Fat tended to be higher for SS and CP was highest for UREA by 60 d (23.8%). CAO had significantly lower fiber portions, ethanol and yeasts (P < 0.05), and higher acetic acid than CONT. No significant differences were observed at 12 and 24 h in situ compared to CONT, yet at 48 h, NDFD was greatest for CONT and SS (P < 0.001). Lactic acid increase with prolonged ensiling with UREA having the highest content at 120 d (0.716 %) and acetic decreased for CONT, SS, and CAO. SS contained the most LAB (8.5 log cfu/ fresh g). Yeasts, molds, and sugars significantly decreased with ensiling. In conclusion, OP was determined to be a viable nutritional source for ruminants given its chemical composition and effective preservation after 120 d of ensiling that could be improved with chemical and bacterial inoculants.

Four experiments were conducted to evaluate the efficacy and safety of a microbial phytase (Novo SP938) in weanling and grower pigs, and starter turkeys fed corn-soybean meal based diets. Pig and turkey BW and pen feed consumption were recorded weekly. Fecal and excreta samples were collected for determination of Ca and P digestibility. At the end of all experiments animals were slaughtered, and 10th ribs or right foot for pigs, and both middle toes for turkeys were removed for bone analysis. In pigs performance, bone measurements, and digestibilities of P and Ca increased as levels of phytase increased. Concentration of P and Ca in the feces decreased as dietary phytase increased. In turkeys, BW gain and toe ash increased as nonphytate P or phytase increased, when added to a low-P diet. Concentrations of P and Ca decreased as phytase was added to the diet. Based on nonlinear or linear equations, the average P equivalency of 500 U phytase/kg feed was .64 and .67 g of inorganic P for pigs and turkeys, respectively. There were no adverse effects of feeding 10,000 U phytase/kg feed in pigs and turkeys. Supplementation with Novo SP938 phytase was effective in improving performance, bone mineralization, P and Ca utilization, and decreasing P and Ca concentrations in the feces of pigs and excreta of young turkeys fed low-P diets, with no health effects, even at very high supplementation rates. / Master of Science

The conflicting problem involving the herds of mule deer (Odocoileus hemionus) are of major interest throughout Utah. Individuals who are affected the most are sportsman, ranchers, fruit growers, sanitation engineers, home owners, federal administrators, and big game managers. Mainly, the problem arise as a result of insufficient forage, especially on the winter range. Here, factors such as increased deer numbers, decreased range productivity, severe winters, and expanded agricultural activity make more acute the problem of a naturally critical season.

The primary objectives of the following experiments were to: 1) determine the impact of a directed microbial (DFM) blend on digestibility and microbial populations on horses fed low (LQ) and high (HQ) quality hay, 2) evaluate the differences in diet digestibility, microbial populations, and blood metabolites due to DFM supplementation to the exercising horse, 3) assess the impact of short-chain fructooligosaccharide (scFOS) supplementation on digestibility and the fecal microbial ecosystem in senior (SR) vs. mature (MA) horses, and 4) determine the relationship between insulin dysregulation (ID) and morphometric neck measurements (MNM) in the non-obese stock-type horse. Results indicated that: 1) Supplementation with DFM tended to be beneficial in enhancing CP digestibility. Feeding CP beyond requirements may contribute to excess excretion of Escherichia coli (EC) in HQ which was supported by 16S rRNA analysis. Differences in the fecal microbial ecosystem were detected between LQ and HQ. The phylum Saccharibacteria was identified in both hay qualities even though it has been lightly reported in equine literature. 2) Supplementing DFM to moderately exercised horses tended to enhance DM and ADF digestibility but there was no evidence of a dietary modulation to the fecal bacteria isolated. 3) No differences were found between MA and SR when fed scFOSded ration balancer which indicates that scFOS may help mitigate decreases in digestibility experienced by SR. Senior horses had less diversity in their fecal bacterial population, which may help explain why SR are more prone to ailments such as colic and impaired immune function. 4) Obesity is an important genetic factor for ID however it should not be the only determining factor, as ID can occur in non-obese individuals. One individual out of 62 tested horses was identified as ID. Morphometric neck measurements (MNM) may help pinpoint horses that are at a greater risk for ID, but more research is needed to validate MNM in both obese and non-obese stock-type horses. There were correlations between glucose sampled before an oral sugar test (OST) and insulin post-OST but a fasting OST would still be recommended in assessing ID.

The objective of this study was to evaluate the relationship between hair coat shedding ability, apparent forage digestibility, and mineral status in Angus cattle. Fecal samples were collected on fall calving Angus cows for one week in March, May, and July from 2019-2022. Liver and plasma samples were collected in March and July each year. Fecal samples were analyzed for DM, ash, NDF, and ADF while liver and plasma were analyzed for mineral concentration. Data were analyzed using MIXED procedure of SAS with significance declared at P0.05. Interactions were detected for DM, NDF, ADF, and liver Fe concentration. The model included MFS, month, and MFS by month interaction for each response variable. Interpretation of results showed no clear trends or associations between hair coat shedding ability, apparent forage digestibility, and mineral status, but further investigation is needed to understand cow performance due to relationships between genes and environment.

ABSTRACT COMPLETION OF AN IN VIVO DIGESTIBILITY TRIAL IN HORSES AND IN VITRO DIGESTIBILITY ASSAY DEVELOPMENT Cassandra Renee Sweeney In vivo analysis of equine feed digestibility has been the gold standard since the late 1800's, although it can be time consuming, costly, and labor intensive. In vitro digestibility analysis may be more economical and beneficial to both feed manufacturers and consumers. The availability of accurate in vivo data is crucial for critical evaluation and validation of any potential in vitro method (Coles et al., 2005). Ten adult American quarter horse geldings were used in the in vivo digestibility evaluation of two complete pelleted feeds fed as 100% of intake. The ingredients of the two treatments were similar: wheat middlings, rice hulls, alfalfa and beet pulp. The treatments differed in added mineral sources, yeast, direct fed microbials, and Yucca schidigera extract, added to enhance dry matter digestibility of the test diet. The in vivo evaluation consisted of two phases in a randomized crossover design. Total daily dry matter intake (DMI) and daily dry matter excretion (DME) were measured. Apparent digestibility (aDig) of % DM, % NDF, % ADF, % ADLom, and % OM (DM) were also calculated. No differences were seen in aDig of NDF, ADF, ADLOM or OM between the two experimental diets (P > 0.05). There was also no difference in DMI or DME, as a percentage of body weight (BW), between the two experimental diets. The effect of phase was not significant for all tests run on aDig, DMI, and DME (P > 0.05). BW was not significantly different (P > 0.05) between diets, however there was a trend for v heavier BW during phase 2 (P = 0.073). In vitro digestibility assay development followed the in vivo evaluation. A three-stage batch system as briefly described by Boisen and Fernandez (1997) was utilized. Through literature review, trial and error, personal communication with other labs and product and chemical manufactures, careful documentation of the methods were detailed. Using the control feed from the in vivo evaluation, variation in the methods was significantly reduced, and estimations of DML began to approach those seen in vivo throughout method development. Although further method development may be needed for species-specific use, the methods described here can provide the foundation for future in vitro digestibility studies.

Soybean meal (SBM) is a staple proteinaceous feedstuff in diets for monogastric animals like poultry and swine. It is known that soybeans contain several anti-nutritional factors that, if untreated, results in decreased quality and bioavailability of amino acids (AA). Thermal processing via heat treatment of soybeans and SBM is essential for inactivation of these anti-nutritional factors; however, over-processing may result in extensive AA damage, particularly lysine. Feeding heat damaged SBM has been proven to be an inefficient source of AA for monogastrics as they cannot be used for any metabolic function. In typical corn-soybean meal diets for pigs and poultry, lysine is the first- and second- limiting AA, respectively. Currently, laboratory procedures are unable to accurately determine digestible lysine in SBM. The objective of this thesis was to compare SBM AA digestibility obtained from 28-day old broilers to values obtained from an in vitro digestion procedure. The correlation between AA concentration in the SBM and its in vivo standardized ileal digestibility (SID) was also analyzed. Twenty-four SBM samples (21 from U.S.A., 2 from Canada, and 1 from Mexico) were analyzed. In vivo lysine SID ranged from 69-93%. Results indicated no correlation (r = -0.16 to 0.21; P = 0.33 to 0.98) between analyzed AA content in SBM and in vivo SID. An increase in lysine SID was associated with an increase in the SID of phenylalanine, leucine, isoleucine, valine, tyrosine, alanine, threonine, glutamate, aspartate, methionine, histidine, and glycine (r² = 0.63 to 0.93; P < 0.001). Poor association was determined between lysine proline, arginine, and serine (r² = 0.14 to 0.43; P = 0.001 to 0.003). Lastly, results indicated no association (r² = 0.00 to 0.08; P = 0.17 to 0.99) between in vivo and in vitro SID for any of the AA tested. In summary, it appears that lysine may be a good indicator for SID estimations for most essential AA; however, SBM content of a particular AA is not a good indicator of its digestibility. Additionally, current in vitro digestibility techniques seemed inadequate in identifying in vivo SID differences and further analytical improvements are needed. / Master of Science

Zinc (Zn) has numerous functions and life sustaining processes depend on the presence of Zn within the body. Zinc sulfate is a common form of Zn supplemented in the beef industry. Inorganic sulfate based minerals have been associated with negative rumen effects, mainly, decreased rumen fermentation and protozoa numbers. Our studies concluded no difference in digestibility of three different forms of Zn (zinc glycinate, zinc sulfate, and zinc hydroxychloride). Although overall digestibility did not change, there were specific mineral concentration differences after steers consumed concentrate treatment for 10 days. These differences implied that the mineral fed was consumed and absorbed in post-treatment sample collection of rumen fluid, plasma, and liver. Overall liver Zn levels were within normal ranges and implies the zn fed was absorbed. Based on the results of this study bioavailability of, zinc glycinate, zinc sulfate, or zinc hydroxychloride were similar.

Two studies were conducted to evaluate cotton gin mote as a forage replacement by determining nutrient digestibility and nitrogen and energy retention. Three diets were used: 0%, 50%, and 100% mote. Dry matter intake was greatest for steers consuming 100% mote. Digestibility of DM, OM, CP, and energy was least for steers consuming 50% mote and greatest for those consuming 0% mote. Digestibility of NDF and ADF was greatest for steers consuming 0% mote. Fat digestibility was greatest by steers consuming 0% mote and least by steers consuming 100% mote, with those consuming 50% mote being intermediate. Steers consuming 0 and 50% mote retained less protein and energy than those consuming 100% mote. In trial 2, IVDMD of cotton gin mote was evaluated to determine rate of disappearance of DM, CP, NDF, and ADF. The 0% mote diet revealed the greatest rate of disappearance for DM, CP, NDF, and ADF, followed by the 50% and 100% mote diet, respectively.