Studies on increasing resilience in dairy and crossbred calves

Pister, Meghan L.

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https://hdl.handle.net/2142/129875 Copy

Description

Title

Studies on increasing resilience in dairy and crossbred calves

Author(s)

Pister, Meghan L.

Issue Date

2025-07-17

Director of Research (if dissertation) or Advisor (if thesis)

Drackley, James K

Doctoral Committee Chair(s)

Drackley, James K

Committee Member(s)

• Cardoso, Felipe C
• Emmert, Jason L
• Loor, Juan J

Department of Study

Animal Sciences

Discipline

Animal Sciences

Degree Granting Institution

University of Illinois Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• calves
• casein
• psyllium
• B vitamins
• plasma protein
• health
• growth

Abstract

Intestinal health is critical for the overall growth and well-being of young dairy calves. Despite advancements in calf management, diarrhea remains the leading cause of morbidity and mortality in this population. While infectious pathogens are often responsible, nutritional factors—particularly diet composition—can also contribute to diarrhea. One such factor is the concentration of total solids (TS) in milk replacer (MR). Feeding MR with high TS levels (e.g., 18%) can enhance nutrient delivery; however, the resulting increase in osmolality may lead to digestive upset and diarrhea. Nutritional strategies—including the addition of electrolytes, fiber sources, and casein protein—may help mitigate these effects. To evaluate these approaches, four experiments were conducted to determine whether high-TS feeding induces diarrhea and whether specific dietary manipulations can reduce its incidence. Results indicated that calves fed high-TS MR experienced a greater incidence of diarrhea and had lower fecal dry matter compared to non-diarrheic calves. Among the interventions tested, the inclusion of casein and psyllium fiber showed promise in reducing diarrhea incidence in one of three trials. This suggests potential benefits, though further research is warranted to confirm consistency across different settings. In addition to managing diarrhea, optimizing vitamin intake is essential, particularly B vitamins, which preweaned calves cannot synthesize independently. Despite their importance, research on ideal supplementation levels remains limited. An experiment was conducted to assess the health and growth outcomes of feeding B vitamins (thiamine, niacin, pyridoxine, and cobalamin) at levels above both the basal diet and the 2021 NASEM recommendations. The results showed that calves receiving only the basal MR diet exhibited fewer cases of ocular discharge, while the basal diet calves tended toward reduced respiratory issues compared to those supplemented above basal levels. No significant differences were observed in body weight or growth parameters between treatment groups. However, analysis of plasma metabolites and hepatic gene expression revealed some distinctions. For example, genes associated with stress response (GR), pyridoxine metabolism (PNPO), and lipid metabolism (ATGL/PNPLA2) showed differential expression, suggesting potential metabolic effects of B vitamin supplementation. These findings indicate that while B vitamin supplementation may influence metabolism, its impact on growth and health outcomes is less clear, and further research with defined dosing is needed. Another area of interest is mitigating heat stress and improving early disease detection in calves. Elevated body temperature is a key indicator of both heat stress and illness, yet measuring rectal temperature (RT) on large-scale farms is time-consuming. Infrared thermography (IRT) offers a non-invasive alternative and has shown promise in detecting illness in livestock. A study was conducted to determine whether IRT could reliably detect elevated body temperature in calves and correlate with RT. Heat stress conditions were defined using a temperature-humidity index (THI). Findings indicated only a weak correlation between infrared surface temperatures and RT. While RT remained relatively stable, IRT readings varied significantly with ambient conditions. Although heat-stressed calves did exhibit elevated internal temperatures compared to their non-stressed counterparts, IRT did not accurately detect fever under the tested conditions. Thus, current IRT methods may not be sufficient for standalone fever detection in calves. Finally, the weaning and immediate post-weaning period present unique challenges for calves, as they transition to solid feed and often face added stress from transport or commingling. During this period, calves may become more susceptible to disease. Plasma protein supplementation has demonstrated health and growth benefits in other species and in calves during the preweaning phase when added to MR, but its efficacy post-weaning is less studied. A study was conducted to evaluate whether including plasma protein in grower feed could improve health and performance in newly weaned calves. Results showed no significant differences in health metrics, growth performance, or plasma cortisol levels between treatment groups. These findings suggest that while plasma protein may offer preweaning benefits, its impact post-weaning requires further investigation, especially with clearly defined stress biomarkers such as cortisol. Together, these studies suggest that targeted nutritional interventions—such as managing TS concentration, optimizing B vitamin supplementation, and using functional feed additives—may have the potential to support calf health and growth. However, the evidence highlights the need for further research to define effective inclusion rates, validate novel diagnostic tools, and refine nutritional strategies for both pre- and post-weaning phases.

Graduation Semester

2025-08

Type of Resource

Thesis

Handle URL

https://hdl.handle.net/2142/129875

Copyright and License Information

© 2025 by Meghan Lynn Pister. All rights reserved.

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