Performing Department
(N/A)
Non Technical Summary
Public concern about farm animal welfare often focuses on the management of pre-weaned animals, with particular attention paid towards social housing, painful procedures such as disbudding in dairy calves and tail-docking in lambs, and weaning. Automated technologies, such as real-time location systems, provide new opportunities to understand social dynamics in group-housed animals through continuous tracking of social interactions. We propose to examine social network analysis as an efficient and objective method for assessing and predicting the welfare of pre-weaned calves and lambs. We will investigate: (1) how early life management practices shape an individual's social development; (2) how an individual's position in their social network predicts response to a painful procedure, and how this response changes their subsequent position in the network; and (3) how an individual's social network position predicts their response to weaning. We expect these findings to provide novel insight into the ability to predict and improve animal welfare through understanding of social interactions. This research will help to (1) advance objective measures of animal welfare using novel, automated tracking technology, and (2) support the development of precision management systems to improve welfare in pre-weaned animals.
Animal Health Component
40%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
(N/A)
Goals / Objectives
This project focuses on assessing social network analysis as an indicator and predictor of welfare in pre-weaned, socially housed animals, with the goal of advancing efficient, noninvasive measures of welfare and supporting the development of precision management systems in socially housed livestock. Specifically, we will investigate: (1) how early life management practices shape an individual's centrality (i.e., how connected they are) in their social network; (2) how an individual's centrality predicts response to a painful procedure, and how this response changes their subsequent position in the network; and (3) how an individual's network centrality predicts response to the weaning transition.
Project Methods
Treatments. We will investigate the effects of a social partner and cauterization in the first week of life on the development of social networks using a 2 x 2 factorial design, with animals cauterized at an Early (2-7 d) or Later (32-37 d) age and assigned to Pair social contact (consecutively born peer in calves or twin in lambs) or Single social contact (individual hutch in calves, or dam only in lambs). Lambs and calves will experience these housing conditions for the first 4 or 10 days of life, respectively. After this period, 4 paired individuals (consisting of 1 cauterized pair and 1 uncauterized pair) and 4 singles (consisting of 2 cauterized individuals and 2 uncauterized individuals) will be moved to a group pen, where they will remain together until weaning. Each pen will be filled with consecutively born animals to minimize age ranges within pens, with a maximum range of 5 d. In total, we will use 96 animals of each species (24 animals/treatment * 4 treatments) housed in groups of 8 individuals (12 groups/species).Disbudding and tail-docking. At 5 days of age, calves assigned to the Early cauterization treatment will be disbudded using the hot-iron method. At 2 days of age, lambs in the Early cauterization treatment will be tail docked using an electric docking iron. At 32-37 days of age, all 4 Later cauterized individuals in a group will be removed from the pen together, cauterized sequentially within 10 min of each other following the procedures described above, and immediately returned to the group. Both cauterization procedures will be performed with local anesthesia and analgesia, given the overwhelming scientific evidence that these procedures are painful and this is unequivocally best practice. However, the effects of local anesthesia and analgesia are short-lasting and research has shown that behavioral and physiological changes still occur in animals receiving pain relief.Weaning. All calves within the group will be gradually weaned from milk simultaneously during a 14-d period beginning when the calves are 43 days old on average, by reducing milk allotment using an incremental step-down program implemented by the automated milk feeder (12 L/d to 2 L/d). Calves will be completely weaned at 56 days of age and will remain in their group pen for 1 week after weaning. Data collection will end after 63 days of age. Ewe milk production will be reduced by removing energy supplement (corn) and lowering forage quality by removing chopped haylage and limit-feeding dry grass hay beginning when the lambs in the group pen are 43 days old on average. Ewes will be removed from the pen when lambs are 56 days of age on average, marking the end of weaning. Lambs will remain in the pen until 63 days of age, after which time data collection will end.Social networks. The day before moving to group housing, individuals will be fitted with collars containing a tracking device that collects data on the animal's location in real-time (TrackLab, Noldus Information Technology, Netherlands). The tracking devices will remain on the animals until weaning at 63 days of age. The tri-axial accelerometer in each tag will be activated to discriminate between lying and standing proximity networks. Each tag will be set to a 1s refresh rate, and will log location and accelerometer data continuously, providing sufficient data to generate robust estimates of the network. We will characterize proximity-based social networks over weekly intervals through weaning. Patterns of social proximity are a meaningful proxy for social behavior, and are associated with other forms of social interaction (e.g., grooming). Individuals' networks will be characterized with three centrality measures to assess how connected they are in their networks: closeness (number of steps to nearest neighbors), strength (sum of an individual's edge weights), and eigenvector (sum of the centralities of an individual's direct and indirect connections).Pain response. To assess behavioral and physiological changes following cauterization at 35 days of age, we will record behavior continuously beginning 48 h before until 48 h after the procedure using video cameras mounted above each pen. In both calves and lambs, we will measure bouts and duration of self-grooming. We will assess activity levels using leg-based accelerometers. Calf-specific behaviors will include frequencies of ear flicks, tail flicks, head shakes, head scratches, and head rubs, as these behaviors change consistently across disbudding studies. In lambs, we will measure previously validated behaviors of tail-docking pain: frequencies of tail wagging, head turning, and foot stamping/kicking; and durations of abnormal lying and walking. To assess the physiological stress response to cauterization at 35 days of age, we will measure fecal cortisol 12 h before (baseline) and 36 h after cauterization. We will sample 36 h after the procedure since plasma cortisol peaks after the local anesthetic and analgesia have worn off (24 hours after the procedure).Response during weaning. From 45-60 days of age, we will assess changes in feeding behavior and activity, and occurrence of abnormal oral behaviors, which can develop in response to hunger and potentially reflect frustration. We will also characterize activity using accelerometers in the tracking tags to measure standing duration and bouts, as an indicator of restlessness. To investigate physiological stress responses to weaning, we will sample hair cortisol from all animals at 63 days of age. Hair cortisol is a relatively novel and non-invasive retrospective measure of long-term HPA activity, that is therefore robust to fluctuations in diurnal rhythms and acute challenges, and has been validated in cattle and sheep. Animal health and performance, including weight gain, will be monitored 3 times per week throughout the pre-weaning period, and averaged to obtain weekly scores.Hypotheses: We hypothesize that: (1) management practices in the first week of life will predict an individual's centrality in their social network in subsequent weeks; (2) there will be a positive bidirectional relationship between an individual's centrality and their resilience to painful procedures; and (3) there will be a positive bidirectional relationship between an individual's centrality and their resilience to weaning.Efforts: We expect the proposed research to generate foundational and applied knowledge for advancing proximity-based networks as an objective measure of animal welfare and inform the development of precision management tools using automated tracking technologies. We will present the results to producers, industry representatives, and the scientific community at extension events and research conferences, statewide and nationwide. We will also use social media and campus outreach events to reach the public and policy makers. For each objective, we will prepare at least one conference paper, one extension article, and one open-access peer-reviewed papers for publication in reputable journals. In total, we expect to generate 6 peer-reviewed publications (3/species).Evaluation: Our team will meet regularly to monitor our progress towards our expected outcomes. We will meet at the beginning of the project to critically review the project objectives, establish the suitability of our approach, and refine as needed. Thereafter, we will meet bi-monthly to critically review our efforts to identify where the project has yet to maximize its potential impact, develop approaches for corrective action, and discuss how well previously identified corrective actions were implemented. All team members will review project outputs, including training SOPs, videos, spreadsheets, publications, and abstracts. At the end of the project, we will critically discuss the project's impact and priorities for future research and outreach efforts.