Progress report for SW22-932
Project Information
For the dairy industry to be financially sustainable, management practices need to meet consumer expectations. Some traditional dairy practices, like calf housing and the use of antibiotics, are the subject of consumer criticism. This project will improve the profitability, sustainability, and quality of life for dairies by identifying ways in which animal welfare and the development of a beneficial gastrointestinal (GI) microbiome can be optimized for dairy calves and brought into line with modern consumer preferences.
This project will investigate how husbandry practices can influence neonatal calf welfare, nutrition and development of the gastrointestinal microbiota, and how these factors contribute to healthy, active and emotionally developed calves that will grow to become productive dairy cows. Recent research has demonstrated how important it is to establish a healthy microbiome early in life and the welfare benefits of paired or group-housed calves, including improved cognitive development, reduced fear responses, and increased curiosity to novel items. In this study, we will investigate the impacts that freezing colostrum has on the structure and function of the GI microbiome and will also determine the effects of paired housing on the development of a healthy microbiome and a healthy calf. We hypothesize that fresh colostrum and paired housing of calves will facilitate the establishment of a healthy GI microbiome and the development of healthy calves, which may lead to more sustainable management practices.
The impacts of feeding frozen or fresh colostrum and housing calves individually or in pairs on welfare and biological functions will be determined. By partnering with commercial dairies and Extension experts, our results will be directly applicable to working dairies and will give them multiple specific tools to develop sustainable calf housing and management systems that meet modern standards of welfare and consumer preference.
Research objectives:
- Characterize the healthy GI microbiome early in life and describe how freezing colostrum and paired housing impact the structure and function of the GI microbiome
- Define welfare benefits of paired or group-housed calves, including improved cognitive development, reduced fear responses, and increased curiosity to novel items.
- Determine if interactions exist between colostrum, social versus single housing, microbiome structure and function, and welfare in dairy calves
Education objectives:
- Educate producers about the importance of social housing and colostrum management for optimal development and long-term productivity of dairy calves, including microbiome differences between calves raised under different colostrum management practices and the effects of paired housing on calf behavior and welfare
Phase 1:
|
|
Days |
Samples/Observations |
|
Colostrum |
0 |
Colostrum samples from each farm and colostrum type will be collected daily for microbiome determination |
|
|
|
|
Phase 2:
|
|
Days |
Samples/Observations |
|
Colostrum |
0 |
Colostrum samples from each farm and colostrum type will be collected for microbiome determination and total solids/proteins Calves fed colostrum |
|
Calves |
0,14,30,60 |
Weight, average daily gain, fecal samples from calves will be collected to determine microbiome changes due to treatments Hair clips for hormone determination (cortisol, dehydroepiandrosterone (DHEA), Triiodothyronine (T3)) |
|
|
0,3,7,14 |
Feces for microbial community profiles |
|
|
3 |
Calf total serum proteins and serum IgG |
|
|
14 |
Calf behavior video recording |
|
|
30 |
Assessment of ruminal development by the presence of rumination |
|
|
daily |
Feed consumption, morbidity scores, mortality, health treatments (type and duration) |
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|
|
|
For both phases, microbiome determination includes an assessment of the types and functions of microbes present in active microbial populations, including pathogen relative abundance, antibiotic-resistance gene types and prevalence.
Phase 3:
After the samples are processed and the findings summarized, during the third year of the study an educational program for dairy producers will be developed and implemented to share our findings about the importance of colostrum management to the development of healthy GI microbiome.
Extension efforts will include newsletter articles and regional workshops to present research results to dairy producers, calf caretakers and dairy allied industry. Website and video material will be produced to demonstrate the feasibility of research-based management practices supported by this project. Methods are detailed in the Education section, below.
Cooperators
- - Producer
- - Producer
- - Producer
Research
Objectives
Phase 1: Characterize and compare viable microbiome in fresh and frozen colostrum from conventional and organic dairies
- determination of types and functions of microbes present in living microbial populations,
- relative abundance of pathogens
- antimicrobial-resistance gene types and prevalence
- statistical comparisons by treatment type
Phase 2: Compare the effects of feeding the two most contrasting colostrum types to calves in paired- versus single-housing
- Colostrum quality
- Calf health
- Weight, feed consumption and average daily weight gain
- Total Serum Proteins
- Morbidity and mortality scores
- Type and duration of treatments
- Calf welfare
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- Non-invasive endocrinological analysis of welfare hormones
- Behavioral observations
- Characterization of the GI microbiome
- Microbial community profiles
- Census of bacterial taxa (phyla, family, genera) in each group
- Statistical comparisons of specific taxa & diversity metrics
- Definition of normal/healthy flora based on correlations with health outcomes
Phase 3: Develop and implement educational program regarding importance of colostrum management, development of healthy GI microbiome, and benefits of proper social development
- The project team, including producers and led by extension representative Betsy Karle, will conduct webinars, field days, workshops on-farm and on-campus, and distribute materials such as fact sheets to dairy stakeholders.
- Evaluation of outreach program effectiveness will be conducted with standard program evaluation criteria guided by logic model and tools such as pre/post surveys of producer attitudes and willingness to implement or suggest changes to housing or colostrum management. The primary goal is to increase knowledge of educational program participants and increase the dairy producer intent to adopt research-based management practices. Actual adoption of practices in this study will be measured on the collaborating farms.
Materials and Methods
The study will be conducted on four partnering commercial dairies. Two of these producer-partner farms follow organic practices and the other two are conventional dairies. The study includes two research phases followed by a third phase dedicated to an educational plan designed to increase knowledge regarding the importance of responsible antibiotic use, calf social development, and the development and management of a healthy GI microbiome. Specific research results from this project will also be publicized to the dairy farming and food animal medicine communities.
The first phase includes two treatments in a 2 x 2 study: Colostrum (fresh or previously frozen) and farm type (organic or conventional). A total of 400 colostrum samples from individual animals will be used in the study, with 100 samples collected assigned to each treatment at each farm. Fresh samples will be immediately snap-frozen in liquid nitrogen for transport back to the lab. The previously frozen samples will be handled the same way after being stored at -20°C for 1 week and being allowed to thaw to room temperature, representing typical conditions of colostrum storage and administration. In the lab, viability PCR will be used in Dr. Oakley’s lab to selectively identify and compare the viable microbial populations in each sample type.
The second phase includes two treatments in a 2 x 2 study: Colostrum (fresh or frozen) and Housing (paired or individual). The two most contrasting colostrum types and farm types will be compared to determine the impact that they have on the microbiome, health and welfare of calves housed in hutches individually or paired. For this phase of the study, 40 calves will be used, with 10 calves assigned to each treatment. Calves will then be placed into either paired housing or individual housing, based on a pre-assigned random list.
All calves in either of these two phases will have access to water and feed from day 1. All calves will be fed the same amount of whole milk (e.g. 6 liters per day to day 7, then 9 liters per day to day 30, then 6 liters per day to weaning). Dry feed (grain) will be provided ad lib and daily feed intakes will be recorded. Calves will be disbudded (if necessary) by day 4 with pain management. Calves will remain on the trial through the milk-fed period (up to 60 days of age), and two weeks into the post-weaned, group housed period.
During the Phase 2, video recordings will be made to determine the presence of relevant behaviors. Calves will be observed in the hutches. Samples of blood or saliva, as appropriate, will be obtained from the calves for the immunological assessments. Hair samples will be collected from the calves for the endocrinological assessment of welfare following the methodology described for dairy cows by one of the co-investigators of the project (Tallo-Parra et al., 2015, 2017 and 2018). Hair cortisol concentrations, as well as from other steroid hormones linked to welfare, reproduction and resilience or metabolism, allow monitoring long-term retrospective levels of the circulating hormone. Steroid concentrations in hair are a potential tool for dairy cattle welfare and production research by providing a useful and practical tool for long-term steroid monitoring.
Physical exams will be conducted on site by trained personnel. Each enrolled calf will be evaluated using numerical scores for fecal and respiratory health at each sampling period.
Fecal samples for microbiome analysis will be collected from each calf at each timepoint listed below. Samples will be placed into sterile collection tubes and frozen by project staff and trained dairy staff. DNA preps, PCRs, and data analysis will be done at WesternU in Dr. Oakley's lab according to previously published protocols.
One full-time employee and three DVM students were hired in 2023. The results to date are detailed for each project objective shown below.
Phase 1: Characterize and compare viable microbiome in fresh and frozen colostrum from conventional and organic dairies
- determination of types and functions of microbes present in living microbial populations,
Using colostrum samples from several local dairies, we have optimized and validated DNA extraction methods as well as viability quantitative-PCR. Following this validation, we have collected 79 fresh colostrum samples from 11 conventional dairies and compared fresh to frozen paired aliquots of each sample. Sample collection for this phase of the project is still ongoing. We are on track for collecting our targets of 100 colostrum samples from conventional and 100 samples from organic dairies by September 2023. We anticipate submitting samples as proposed for high-throughput DNA sequencing (HTS) in Fall 2023.
- relative abundance of pathogens
The HTS will be the main method to answer this question. In the meanwhile, we have adopted and used a Mycoplasma bovis-specific PCR assay to screen samples for this important pathogen. All samples screened to date have been negative and the detection assay is being refined.
- antimicrobial-resistance gene types and prevalence
The HTS will be the main method to answer this question.
- statistical comparisons by treatment type
For samples collected to date, we have observed small but statistically significant decreases in the abundance of viable microbes associated with freezing of colostrum, particularly freezing over extended periods of time. Ongoing work is confirming these results.
Research Outcomes
Education and Outreach
Participation Summary:
We are in the initial stages of the project and have no final results to report, so no educational or outreach events have been organized yet.
One of the DVM students hired on the project is representing our research team by presenting a poster summarizing the results of the studies we have conducted to date at the National Veterinary Students and Scholars annual conference in August 2023 in San Juan, Puerto Rico.