Recipient Organization
UNIV OF MINNESOTA
1035 UNIVERSITY DR
DULUTH,MN 55812-3011
Performing Department
WCROC
Non Technical Summary
The long-term goal of this project is to increase and sustain organic dairy production and animal welfare through breaking barriers to organic dairy transition. One of the major barriers preventing transition to organic dairy production is dairy producers' concerns about disbudding dairy calves and the challenges with animal health and welfare in an organic production system. Furthermore, finding suitable polled genetics for dairy herds may be challenging for all farmers. The present proposal addresses these challenges through research involving the University of Minnesota's West Central and Research Center's certified organic dairy herd. We will develop methods to investigate the management feasibility to address pain and alternative options for disbudding fordairy farms. We will identify suitable polled genetics for use in breeding for dairy herds. We will also evaluate markers of calf health, behavior, and welfare to ultimately provide recommendations on best calf disbudding options for producers. Holstein and crossbred calves will be compared across and within each calf disbudding or polled option. The results of this project will be valuable to dairy producers and will be disseminated to transitioning and organic producers and industry representatives throughout the United States. Our research results will be shared with our larger stakeholder groups through field days, conferences, publications, and webinars. Results from this study will provide research-based information on best options for polled genetics, pain management and disbudding in young calves which will help enhance the profitabiltity of US organic dairy farms and improve dairy industry's public perception.
Animal Health Component
100%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Goals / Objectives
The organic dairy industry is in desperate need of methods to improve animal welfare, and horn removal represents a major identified issue threatening the industry's public image. Critics of the organic dairy industry constantly express concern about practices that jeopardize animal welfare, such as usage of alternative therapies that lack scientific proof of effectiveness. Furthermore, the use of unproven alternative therapies does not meet the legal requirements set by the National Organic Program.Our goal is to identify and recommend management practices for disbudding young calves and incorporating polled genetics that will address a challenge but also likely provide a market opportunity for all dairy producers, therefore improving dairy farm profitability.Producers and veterinarians of organic dairy cattle often express their need for evidence- based information concerning the efficacy of organic-approved treatments and polled genetics management to reduce the adverse effects of disbudding on animal welfare. This project proposes to address an important portion of stakeholder critical needs by evaluating polled genetics and conducting controlled experiments to evaluate organic-approved treatments to mitigate acute pain caused by the disbudding procedure, and to evaluate long-term effects of polled genetics disbudding on animal welfare in organic systems.Specific objectives are: 1)To identify the most suitable polled sires for breeding organic dairy herds with the existing UMN research dairy herd and from US DHIA data, 2)To evaluate differences in pain and sensitivity, behavior, and handling between polled and horned calves in the weeks following hot-iron disbudding, and 3)Evaluate differences in agonistic interactions between disbudded, polled, and horned cattle and evaluate the effects of selecting for polled cattle on production measures.The success of this project will beevaluated by acceptance and implication of the project findings by dairy farmers, and publications in farmer magazines, on extension websites, and in peer reviewed journals.
Project Methods
Organic farm data will be provided by Dairy Herd Improvement Association (DHIA) and will be edited and organized in lactation records, differentiating polled and non-polled. The DHIA data is monthly national milk sample testing data that farmers use for management of their herds. Data from individual cows will be the base for herd level calculations (herd size, milk production, milk quality, fertility, etc.). Files will be prepared in a format that is adequate for the subsequent analyses to be completed with SAS (SAS institute Inc., Cary, NC). Statistical analyses will depend on the nature of the variables under analysis (continuous/categorical). Briefly, ANOVA, logistic regression, and time to event analysis will be considered for the analyses. The focus will be placed on characterizing polled genetics at the individual and at the herd level, comparing variables related to the cow and the herd, as well as considering the organic status of farms. We will also use cluster analyses to find groups of farms with similar polled genetics, allowing for more dedicated control options. For evaluation of polled genetics for use in organic dairy herds, sires will be identified using the Complete List of Active, Foreign, and Genomic sires in the US and foreign countries for all breeds of dairy cattle. Data provided by the US Council on Dairy Cattle Breeding and NAAB on all homozygous and heterozygous polled dairy sires will be compiled in a Microsoft Excel® spreadsheet; this includes health and fertility, calving traits, indexes, production traits, and linear traits, as well as identifying information. For the WCROC dairy herd, homozygous and heterozygous polled dairy sires will be selected based on Net Merit within breed or with each country's ranking indices. Additional consideration will be given to semen price and availability and mating will be completed to minimize inbreeding. Sires and cows will be matched using the scenario described by Spurlock et al. (2014), which resulted in 87% polled animals: horned cows will be mated to homozygous polled bulls, heterozygous cows to heterozygous bulls, and homozygous polled cows to horned bulls. Selective breeding for polled genetics should account for approximately one-third of calves born in a particular season. The other two-thirds will be bred as usual for the WCROC breeding program. To complete the second and third objectives of this proposal, ideally at least 18 calves will be born in a single season with the polled phenotype and 36 will be born with the horned phenotype (N = 54; Objective 2). However, additional calves would be useful to prevent issues due to animal attrition. Increasing the minimum group size by roughly 30% brings the sample size to 24 calves per group (N = 72; Objective 3). If necessary due to lack of available polled sires, the study may continue into a second calving season to achieve the desired sample size. For Objective 3.2, results from (Gehrke et al., 2016) were utilized to calculate minimum sample size. A power analysis run with SAS ® using group mean values for milk yield, protein yield, and fat yield suggested a minimum sample size of 13, 10, and 12 per group, respectively, to achieve 90% power at a 0.05 alpha level. Inflating these results by 30% would bring the minimum sample size to 17. All polled calves included in objectives 2 and 3.1 will therefore be enrolled in objective 3.2, and an equal number of calves born with the horned phenotype will be enrolled as well. Objective 2 will be tested utilizing a generalized randomized complete block design with repeated measures. The study will ideally be performed during one calving season; however, as previously stated, it may be spread across multiple calving seasons as necessary for reaching a large enough sample size for statistical power. Calves included in the study will be at least 5 weeks of age at the time of disbudding. The study will begin for a particular pen when the youngest calf within that pen is 4 weeks of age to account for the 7-day acclimation period. Within each pen, 3 calves will be assigned to each of the following three treatments: 1) Disbudded (positive control; n = 18), 2) Polled (negative control; n = 18), or3)Horned (n = 18). All calves born with the polled phenotype will be included in the study as the "polled" treatment group; calves born with the horned phenotype will be randomly assigned to the "disbudded" and "horned" treatment groups, balanced for breed, until all groups are of equal sample size. Because calves are assigned to pens based on birth order, there may need to be some flexibility depending on when polled calves are born; however, an effort should be made to ensure that pens contain an equal number of calves per treatment group. Calves in the "disbudded" treatment will receive a local anesthetic, lidocaine (5 mL per horn bud of 2% lidocaine. To ensure the anesthesia has been administered successfully, a handler will conduct a prick test around each horn bud; an additional 2 mL of lidocaine will be administered to calves that respond to the prick. A handler will perform the hot-iron disbudding. All animals included in Objective 2 will also be enrolled in Objective 3.1 and 3.2. The study will be conducted when heifers are approximately a year old, once during the summer on pasture and once in the fall in loose housing. By this age, all heifers of the same season are merged into one group on pasture or in a loose barn, depending on the season. Heifers were previously divided into three treatment groups (disbudded, polled, and horned) for Objective 2.Direct visual observations will be conducted by at least two observers, with each observer assigned to specific animals. A camera will record video during observation sessions to supplement direct observations. A preliminary video will be recorded and used to assess inter- observer reliability prior to the start of the study (Kaufman and Rosenthal, 2009); reliability between observers will be measured using Cohen's kappa. A photograph of each heifer will be taken prior to the study to assist observers with identification. Heifers will be observed in focal groups coinciding with their original assigned "pens" as calves; that is, during any hour-long session, only the heifers from a particular pen will be observed. This ensures that three heifers of each treatment group are observed per session. Observations will occur in both the pasture during the summer and the loose barn during the fall, one month after heifers are moved to either location. Focal heifers will be observed 6 times per location, 3 times in the morning and 3 times in the afternoon, over the course of two weeks. Treatments. Within a pen of 8, all calves will be randomly assigned to a disbudding treatment group: 1)Not disbudded (control; n = 72) or 2)Disbudded (n = 72). Calves in the disbudding group will be hot iron disbudded with lidocaine in a similar manner described in Objective 2. Pens will be weaned when the youngest calf reaches 60 days of age according to standard management procedures.