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<p> Research has shown that direct-fed microbials (DFM) and enzyme supplementation can impact the dry matter intake (DMI), milk production, and milk composition. However, limited research has evaluated the impact of DFM and enzyme supplementation on colostrum quality and the uptake of the Immunoglobulins A and G (IgA and IgG) by calves. In this study, 36 multiparous Holstein cows were blocked by expected calving date and randomly assigned to 1 of 3 treatments 3 weeks prior to calving and remained on these treatments until week 8 postpartum. These treatments were: 1) 0 g of DFM and enzyme (control), 2) 45.40 g/d of Tri-Lution&reg; (Tri), or 3) 45.40 g/d of Tri-Lution&reg; and 18.16 g/d of Zy-mend&reg; (Tri + Zy). The amount of total mixed ration (TMR) fed and orts refused were measured each day to determine DMI. Blood samples were taken on the cows every Monday, Wednesday, and Friday at 1100 h from the coccygeal veins and arteries to be analyzed for &beta;-hydroxybutyrate (BHBA), glucose, and nonesterified fatty acids (NEFA). Cows were also weighed once a week throughout the course of the study. Colostrum was harvested and weighed at parturition and later analyzed for IgA and IgG concentration via radial immunoassay. Calves were fed 4 L of maternal colostrum within 2 h after calving. Blood samples were also taken from the calves at 0 and 24 h in order to be analyzed for IgA and IgGconcentrations and to determine apparent efficiency of absorption of IgA and IgG. Finally, milk yields were taken daily for 8 wk postpartum and samples were taken once a week and sent to DairyOne (Ithaca, NY) to be analyzed for quality. Prepartum body weight (BW), BW, efficiency of gain, DMI, BHBA, NEFA, and glucose concentrations were not impacted by treatment. There was also no impact of treatment on colostrum yield, IgA and IgG content, and composition with the exception of IgA yield and ash percentage. The ash percentage of colostrum tended (<i>P</i> = 0.07) to increase with the Tri and Tri + Zy treatments while the IgA yield (<i>P</i> = 0.05) decreased with the Tri treatment. Treatments did not impact BW, serum IgA and IgG concentrations or apparent efficiency of absorption of IgA and IgG of the calves. Postpartum BW, DMI, blood metabolites, milk production and composition, with the exception of BW gain and somatic cell score (SCS), of the cows were not impacted by treatment. Cows on the Tri treatment gained more BW (<i>P</i> =0.03) and tended to have a greater efficiency of gain (<i>P</i> = 0.09) in comparison to those on the Tri + Zy treatment, but both treatments did not differ from the control. This suggests that there is a negative effect of applying the Tri-Lution&reg; and Zy-mend&reg; together which might be due to negative interactions among ingredients and microorganisms. An increase in SCS (<i>P</i> = 0.04) was also observed with the Tri treatment. All these results indicate that the supplementation of DFM and enzymes is not beneficial in improving the health and performance of dairy cattle during the transition period and early lactation.</p>

Alcoholism is a serious illness that is marked by uncontrollable drinking and physical dependence to alcohol. Long-term alcoholism has been linked to many health concerns such as cirrhosis of the liver and cardiovascular disease. Alcohol is one of the most commonly used drugs among adolescent populations. Given that adolescence is a unique developmental stage during which alcohol has long-term effects on future drug-taking behavior; it is essential to understand how early exposure to alcohol during adolescence may affect the abuse liability of the drug later in life. Indeed, most alcohol users start during adolescence suggesting that exposure to alcohol during adolescence increases the risk of alcohol abuse in adulthood. Our studies focus on identifying behavioral mechanisms involved in alcohol dependence during adolescence by using well-established mouse models of alcohol drinking. Our hypothesis is that exposure to alcohol during early adolescence will increase alcohol intake later in adulthood. We investigated the impact of alcohol drinking in male and female early adolescent C57BL/6J mice using the Drinking In the Dark (DID) model. Our results showed that exposure to alcohol during early adolescence enhanced ethanol intake later in adulthood in the DID and the 2-bottle choice drinking paradigms. In contrast, adult exposure of alcohol did not enhance later alcohol intake. Our data illustrates that enhanced alcohol intake are affected by the duration, age of exposure, and mouse genotype. In addition, we conducted behavioral studies to elucidate in part the mechanisms underlining the relationship between adolescent ethanol exposures and enhance alcohol intake in adult mice. We hypothesized that these changes in alcohol intake are due to an alteration between ethanol aversive and rewarding properties. Our results showed that ethanol exposure during adolescence induces a less aversive state (less withdrawal intensity in the FST test) later in adulthood. In contrast, our results showed that ethanol exposure in adolescence enhanced the rewarding properties of ethanol in the CPP test and alcohol intoxication (as measured by the LORR test). Overall, our results suggested that this increase in the alcohol intake was correlated with an increase in alcohol rewarding properties and a reduction of alcohol aversive effects. Further research will be required in order to more fully examine the mechanisms of action for the observed changes in alcohol intake.

Master of Science / Department of Animal Science and Industry / Micheal J. Brouk / Data obtained from 50 individual published studies recording water intake by dairy cattle were utilized in a meta-analysis to develop a prediction equation for free water intake (FWI). Studies were selected based on quantitative measurements of DMI, diet DM%, water intake (WI), and milk yield. Many of the studies determined FWI on multiple treatments resulting in 116 mean data points from the 50 studies. With the addition of Na in the meta-analysis, 40 data points were available from the studies to examine the effects of Na on FWI. The effects of DMI, ration water intake (RWI), and milk yield (MY) were used to develop a FWI prediction equation from the 116 data points. The effects of DMI, RWI, MY, and sodium intake were used to develop a second prediction equation from the 40 data points. These equations were then compared with five published FWI prediction equations from Castle and Thomas (1975), Dahlborn et al. (1998), Little and Shaw (1978), Murphy et al. (1983) and Stockdale and King (1983). This data set showed that the five published equations either over or under predicted (P < 0.05) FWI when compared the actual FWI calculated from the meta-analysis data points. It also showed that the equation developed from the meta-analysis data points is the more accurate in determining FWI from the data points selected from the studies. A second project was conducted with the fresh water data collected from 13 freestall (FS) and 11 dry lot (DL) Kansas dairies over a 10-year period (2000-2009). Fresh water was recorded from water pumping records. Data were first summarized annually by operation and then converted to a per cow per day basis prior to analysis. Data were then analyzed by using the mixed procedures of SAS. Fixed effects included in the model were dairy type (FS or DL) and year was considered a random effect. The DL dairies averaged 186 L/cow per day and were lower than the FS dairies which averaged 237 L/cow per day. Differences between DL and FS style dairies may have been due to differences in parlor fresh water usage or cow cooling systems.

Doctor of Philosophy / Department of Animal Sciences and Industry / J. S. Drouillard / The first chapter of this dissertation reviews factors affecting E. coli O157:H7 prevalence in the gastrointestinal tracts of cattle. Chapter 2 assessed E. coli O157:H7 ability to use bovine intestinal mucus and its constituents as substrates for growth in vitro in the presence and absence of fecal inoculum and exogenous enzymes. Whole mucus supported the greatest pathogen growth (P < 0.05), but all components tested were able to sustain E. coli growth. Chapter 3 evaluated the impact of crude glycerin feeding on E. coli O157 fecal shedding by cattle fed growing and finishing feedlot diets with corn or a combination of corn, distiller’s grains, and soybean hulls. Increasing levels of crude glycerin decreased incidence of E. coli O157 in growing cattle (linear effect, P < 0.01) and tended to do so in finishing cattle fed corn-based diets (P < 0.06). No effect of glycerin was observed in finishing cattle fed the byproduct-based diets (P > 0.05), highlighting potential for glycerin use as a means for controlling fecal prevalence of E. coli O157 in cattle fed conventional grain-based diets. Chapter 4 evaluated transportation and lairage effects on fecal shedding of E. coli in feedlot cattle by mimicking transport to the abattoir. Shedding patterns were influenced by transportation, with significantly lower E. coli O157 prevalence in transported animals 4 hours after transit (P < 0.05). Additional post-transit samplings are, however, needed to confirm effects of transport stress on pathogen prevalence and shedding patterns. The experiment summarized in chapter 5 evaluated the potential for utilizing fecal long-chain fatty acid (LCFA) profiles as an indicator of E. coli O157 status. Out of 39 LCFA evaluated, only eicosapentaenoic acid (EPA) concentration was associated with presence of the pathogen (P < 0.02). The final chapter assessed the impact of dietary menthol, up to 0.3% of diet DM, on antimicrobial resistance in commensal E. coli. Menthol addition affected prevalence of tetracycline resistant E. coli, but contrary to our hypothesis, increased their occurrence after 30 days of treatment (P < 0.006). No hypothesis on mechanism responsible for this increase could be made from the present study.

Doctor of Philosophy / Department of Animal Sciences and Industry / KC Olson / The objective of this series of studies was to develop and improve methods of production in cow/calf operations of the Great Plains. Ultrasound measures of longissimus muscle depth (LMD) and intramuscular fat (IMF) of Angus × heifers were used to predict lifetime cow productivity. IMF and LMD were categorized into high, medium, and low groups (IMFG and LMDG, respectively). Cows in the high and medium LMDG had greater (P < 0.05) pregnancy rates than cows in the low LMDG. Calf BW at weaning increased (P < 0.05) as dam IMF increased. Angus crossbred cows grazing native range were used to evaluate the effects of pre-partum ruminally-protected choline (RPC) supplementation on postpartum beef cow and calf performance. Under the conditions of our study, RPC supplementation had minimal (P > 0.05) effects on pregnancy rates and performance of beef cows and calves. Lactating crossbred cows with calves and non-pregnant, non-lactating Boer-cross nannies were used to evaluate the effects of co-grazing on herbivory patterns and animal performance while grazing native tallgrass rangeland infested heavily by sericea lespedeza (SL). The proportion of individual SL plants that had been grazed at the end of the trial was greater (P < 0.01) in co-grazed pastures than in single-species pastures. Grazing cows and goats in combination increased (P < 0.01) grazing pressure on SL without negatively affecting beef cow performance, beef calf performance, or residual forage biomass. Angus × cows and heifers grazing native range were used to evaluate the effects of pre-partum corn steep liquor supplementation on postpartum beef cow and calf performance. Under the conditions of our study, CSL supplementation did not generally promote beef cow and calf performance that was equivalent to supplementation with an isonitrogenous, dry, corn-soy alternative. Cow calf pairs were used to evaluate the effects of grazing system (GS) and stocking rate (SR) on cow and calf performance. Late season rest-rotation (LSRR) was compared with continuous (CONT) grazing at low, moderate, and high SR. Under the conditions of our study, CONT produced consistently better (P < 0.01) late-season cow and calf performance than LSRR. Season-long effects of SR on animal performance were minimal; moreover, GS and SR treatments produced equivalent pregnancy rates.

Doctor of Philosophy / Department of Diagnostic Medicine/Pathobiology / Steven S. Dritz / A total of 8 experiments and a meta-analysis were performed with the overarching goal to improve amino acid and energy utilization in swine diets. The first experiment used a total of 255 nursery pigs to evaluate the optimum dietary standardized ileal digestible (SID) tryptophan to lysine (Trp:Lys) ratio. Four experiments also were conducted using 6,668 finishing pigs to determine the effects of SID Trp:Lys ratio in diets containing dried distillers grains with solubles (DDGS) on growth performance and carcass characteristics. A subsequent experiment evaluated the interaction between Trp and large neutral amino acids (Trp:LNAA) on growth performance of early and late-finishing pigs. Lastly, data from 41 trials and 2 validation trials were used to develop a regression equations to predict ADG or gain to feed (G:F) as influenced by BW and net energy (NE) content in growing-finishing pigs. In Exp. 1, the growth performance and economics indicated the optimum SID Trp concentration for 6-to 10-kg nursery pigs at 20.3% of Lys. In Exp. 2, 3, and 4, there were no differences in growth performance due to SID Trp:Lys ratio; however, increasing the SID Trp:Lys ratio suggested an opportunity to improve carcass yield and lean in pigs fed high levels of DDGS. Experiment 5 indicated an optimum SID Trp:Lys ratio of 20% for 71- to 127-kg pigs fed high level of DDGS. In Exp. 6, growth performance was unaffected by dietary treatment suggesting that 16.5% SID Trp:Lys was adequate to prevent a negative impact on growth when SID Trp:LNAA was as low as 3.0% in finishing period. Overall, the experiments suggested a higher optimum SID Trp:Lys ratio than is currently standard practice. The regression analysis from the meta-analysis showed that increasing dietary NE improved ADG and G:F. However, the magnitude of improvement will be minimized if the SID Lys concentration is limiting. The validation experiments indicated that the prediction equations provided a good estimation of growth rate and feed efficiency of growing-finishing pigs fed different levels of dietary NE except for pigs fed the diet with DDGS. These predictions of growth performance can then be used to model economic value of different dietary energy strategies.

Master of Science / Department of Animal Sciences and Industry / Jeffrey S. Stevenson / The objectives were to evaluate the effects of equine chorionic gonadotropin (eCG) administration on preovulatory follicle diameter, serum estradiol and progesterone concentration, corpus luteum (CL) diameter, estrual activity, and pregnancy rate. Lactating dairy cows were submitted to a Presynch-Ovsynch timed artificial insemination (TAI) protocol. Cows (n = 121) in a single herd were treated with 2 injections of prostaglandin F2α (PGF) 14 d apart (Presynch), with the second injection administered 11 d before the onset of a timed AI protocol (Ovsynch; injection of GnRH 7 d before and 56 h after PGF2α, with TAI administered 16 to 18 h after the second GnRH injection). Cows were assigned randomly to receive either saline or 400 IU eCG concurrent with the PGF2α injection of the Ovsynch protocol (d 0). Blood samples were collected during the study to monitor serum changes in progesterone and estradiol to determine if eCG would facilitate increased estrual activity, improved ovulatory response to GnRH, and enhanced post-ovulatory luteal function. Administration of eCG tended to increase the number of CL and on d 9 and 16 after PGF2α, corresponding to d 6 and 13 post-ovulation. Volume of the post-eCG treatment luteal tissue was increased only on d 16. Timed AI pregnancy rates did not differ between eCG (36.9%) and control cows (41.8%). We concluded that use of eCG provided no profertility advantages to dairy cattle when programmed for a timed insemination at first service.

Doctor of Philosophy / Department of Animal Sciences and Industry / K.C. Olson / Sericea lespedeza (SL; Lespedeza cuneata) is classified as an invasive plant throughout the Great Plains. It infests over 600,000 acres in Kansas. Increasing grazing pressure on SL may reduce seed production and slow the spread of the plant; however, intake of SL by grazing beef cattle is poor, due to the presence of tannins in the plant. Condensed tannins reduce protein digestion by ruminants and may also decrease plant palatability. Detailed study of the appetite-suppressing effects of SL under controlled conditions is essential in order to develop appropriate strategies to increase grazing pressure on this plant. Such information could lead to a degree of biological control of this noxious weed using domestic herbivores. We compared intakes of tallgrass prairie hay by beef cows when hay was either uncontaminated or heavily contaminated by SL. Beef cows fed contaminated hay exhibited a profound aversion to compared to similar uncontaminated hay. Furthermore, differences in voluntary DMI between contaminated and uncontaminated hays of similar chemical composition were manifested rapidly after introduction of contaminated hay into beef cow diets. Supplementation with corn steep liquor (CSL) increased tolerance of beef cows for SL. It ameliorated the negative consequences of tannin consumption in a dose-dependent manner when fed to beef cows in confinement. The beef cows in our study had only limited opportunity to selectively avoid SL because it was offered in chopped form and in a mixture with other forage species. It was unknown if beef cattle supplemented with CSL would readily consume forage contaminated by SL when uncontaminated forage was available simultaneously. Therefore, we examined the effects of CSL fed to beef cows on voluntary selection of tallgrass prairie hay contaminated by SL when uncontaminated tallgrass prairie hay was also available. Supplemental CSL (0.6 kg DM/d) increased both acceptance of and tolerance for SL by beef cows. It ameliorated some of the negative consequences of tannin consumption on digestible DM intake. In addition, voluntary consumption of SL-contaminated forage increased by 25% in supplemented vs. unsupplemented beef cows. It is unknown if supplemental CSL can promote voluntary selection of actively-growing SL by beef cattle grazing native rangeland in the Kansas Flint Hills.

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