Juan_Castro Marquez

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ABSTRACT Digestive problems are common in calves between birth and weaning, and about 25% of pre-weaned heifer population in the US commonly presents diarrhea. Moreover, about 57% of the mortality in pre-weaned heifers is due to diarrheal disease. Costs associated with high mortality and reduced productivity exceed $200 million annually. Part of the problem is that methods to assess gut health in pre-weaning dairy calves at the farm level are not well defined. Aside from sound facility hygiene protocols, there is a lack of effective preventive gut health schemes and mostly ex-post therapeutic schemes are available. Development of complementary ex-ante quantitative models based on gut health measures at the calf and tissue level could help prevent disease. Here, results from analysis of calf level data are reported, where quantitative changes in calf gut health throughout the first month of life as measured by fecal scores, and their relationship with thermal variability, blood protein and bodyweight at birth, are described. We also assessed the changes in calf gut health as measured by intestinal paracellular permeability in response to age, failure of passive transfer, and intestinal location. Analysis of fecal score data indicated that risk for intestinal disease changed hyperbolically from 5 to 35 days with a risk peak around 13 days of age (~0.7), which agrees with previous reports in the literature. The variations in time, however, depended on the calfspecific features noted above, suggesting that variables related to thermal homeostasis, passive immunity obtained by the calf, and variables related to fetal maturity in early life might influence the risk of diarrheal episodes. However, the direction and size of such effects were not consistent and seem to be dependent upon other unknown variables that evolve over time. ii
On the other hand, gut health as measured by paracellular permeability in Ussing chambers appeared not to be intrinsically related with time but colon appeared to be the tissue having the largest changes in permeability compared to other GIT regions. Also, failure of passive transfer appeared to have no influence on gut health at the tissue level even though it reduced the odds (0.84/day) of scour episodes at the calf level. More data on intestinal permeability should be collected in response to key predictor variables. Furthermore, indicators of gut health other than just permeability need to be evaluated for development and implementation of quantitative models to be feasible. Specific areas of search for risk factors, including calf immune, intestinal pathogen load and metabolomic/metabonomic profiling appear to be promissing for development of calf and tissue level empirical prediction models that support individual calf preventive care protocols. Another portion of this research related to the assessment of the effect of age and gastrointestinal location (rumen vs colon) on microbiota diversity and composition, and shortchain fatty acid profiles of Holstein pre-ruminant calves. Compared to rumen, higher lactic acid bacteria abundance (e.g. Lactobacillus: 51 vs 2 %, p < 0.001) and high concentrations of lactate (0.1 vs 1.5 mmol/mL, p
Page 1: CALF INTESTINAL HEALTH: ASSESSMENT
Page 5 and 6: ACKNOWLEDGEMENTS I must thank my pa
Page 7 and 8: DISCUSSION ........................
Page 9 and 10: The resultant growth delay may have
Page 11 and 12: High [cAMP] causes Cl - secretion i
Page 13 and 14: paracellular flux, possibly due to
Page 15 and 16: Finally, thorough understanding of
Page 17 and 18: Soberon, F., E. Raffrenato, R. W. E
Page 19 and 20: On the other hand, gut health as me
Page 21 and 22: At the farm level though, these sco
Page 23 and 24: of the new born calf with the proba
Page 25 and 26: From exploratory plots (Figure 2.1)
Page 27 and 28: transported to the laboratory for i
Page 29 and 30: hypothesized, a quadratic function
Page 31 and 32: Effect of age, GIT region and FPT o
Page 33 and 34: coefficients vary from one to the o
Page 35 and 36: passive immunity status (Chase et a
Page 37 and 38: mucosa (Wyatt, 2000). Thus, for ins
Page 39 and 40: Finally, more indicators of gut hea
Page 41 and 42: Table 2.2. Estimated fixed effects,
Page 43 and 44: Table 2.5. Effect of GIT locations,
Page 45 and 46: a b c d Figure 2.1. Exploratory plo
Page 47 and 48: Figure 2.4.Estimated probability of
Page 49 and 50: NAHMS. 2010. National animal health
Page 51 and 52: CHAPTER III MICROBIOTA COMPOSITION
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considered a monogastric (Orskov, 1
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MATERIALS AND METHODS Animals, Feed
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their nearest relative with a seque
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Microbial Community Composition. Th
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Intestinal SCFA Concentrations. Col
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ages, there is a visually evident d
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for most of the abundance differenc
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The PERMANOVA results (Table 3.13)
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In contrast, the rumen underwent ma
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lactate metabolism through extensiv
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CONCLUSION The rumen and colon of i
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Table 3.3. Regression coefficients
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Table 3.8. Contribution by specific
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Table 3.10. Indicator index values
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Figure 3.1. Richness and Shannon In
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a) b) Stress: 0.18 Stress: 0.18 c)
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Bacterial motility proteins Aromati
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REFERENCES Anderson, M. J. 2001. A
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Gibson, G. R. and X. Wang. 1994. Re
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Sutton, J. D., A. D. McGilliard, M.
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than GOS supplemented animals. Size
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score and, within block, treatments
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from which 5 µm thick sections wer
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Afterwards, to visually explore the
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to estimate the expected number of
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abundance of one or many of the sev
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characterized by more abundant Lact
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Visceral Organs Size Supplementatio
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Average daily water intake at 2, 4
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absorptive capacities are progressi
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Regarding functionality, the transp
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TABLES AND FIGURES Table 4.1. Nutri
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Table 4.5. SIMPER for genera drivin
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Table 4.7. Regression coefficients
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Table 4.11. Least squares means ±
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Table 4.15. Least squares means ±
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Lactobacillus Clostridium Square ro
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REFERENCES Anderson, M. J. 2001. A
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Heinrichs, A., C. Jones and B. Hein
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CHAPTER V EVALUATION OF VARIOUS ADD
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of the umami flavor, into the duode
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Dosing of glucose was based on prev
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3% hydrogen peroxide (15 min). Sect
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Genes selected to represent the GLP
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protein were tested as covariates.
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significant. Table 5.5 and Figure 5
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(average calf BW = 50 kg), which, f
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species specific dose response surf
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Table 5.2. Gene ID, accession numbe
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Table 5.4. Treatment means for plas
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a b 3OMG Control Gluc Sweet GS 3OMG
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R = 0.8, p < 0.001 Figure 5.3. NMDS
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Margolskee, R. F., J. Dyer, Z. Kokr
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Juan_Castro Marquez

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