Performing Department
(N/A)
Non Technical Summary
Early life experiences, including social contact, nutritional planes, and cognitive stimulation, have fundamental impacts on the physiological and behavioral development of dairy cattle. These experiences impact their welfare and productivity throughout their lives. Substantial research has documented the impact of early life environments on immediate calf welfare and performance but there is a knowledge gap regarding the impact of rearing environments of preweaned calves on resiliency and longevity as calves transition to lactating cows. From birth to culling, dairy calves and cows are exposed to a myriad of physical and environmental stressors. Resilient dairy cattle that cope well with stressors in dairy production systems are expected to have better long-term welfare and improved productivity. The proposed project addresses how early-life calf management affects their long-term behavioral development, emotional states, and physiological biomarkers of stress, by examining conventional management compared to combinations of social, nutritional, and cognitively enhanced environments. One experiment will investigate the impact of 1) an enhanced nutritional/social/cognitive environment, 2) an enhanced nutritional environment, or 3) a conventional environment on behavioral patterns (personality), physiological and neural stress biomarkers, and emotional states at key life stages as calves progress through the production system into adulthood. Another experiment performed on commercial farms will use the aforementioned measures to identify characteristics of resilient cows, defined as positive emotional states, high production, and a long herd life. Project results will aid with the goal of the U.S. dairy industry to increase longevity of dairy cattle and improve animal welfare and standards of care.
Animal Health Component
100%
Research Effort Categories
Basic
20%
Applied
80%
Developmental
0%
Goals / Objectives
The ultimate goal of this study is to disentangle the influence of each factor and to understand the longterm impact of early-life management practices on animal welfare and resilience to challenges, and to characterize traits of resilient animals. To accomplish this, we propose the following primary objectives: Objective 1: To evaluate the impact of conventional and enhanced early-life management environments (social, nutritional, sensory, and emotional enrichments) on calf resilience indicated by long-term positive behavioral and affective animal welfare indicators and performance at various life stages.Objective 2: To evaluate the impact of conventional and enhanced early-life management environments on calf resilience indicated by long-term physiological and neural biomarkers of stress resilience, and relationship between these biomarkers with performance and longevity.Objective 3: To identify key personality, behavioral, and physiological markers measured during the pre-weaning period that are associated with resilience and longevity from birth through the first lactation.We hypothesize that calves reared in an enhanced early-life environment will have greater positive welfare and resilience, indicated by more curious or exploratory personalities; greater optimism, suggestive of a positive emotional state; reduced physiological biomarkers of stress resilience; and increased neural biomarkers of cognitive function. In turn, these are expected to improve performance metrics, such as pre- and post-weaning weight gain, first lactation milk yield and increased productive longevity. We hypothesize that enhanced nutrition only in early life will influence performance, but none of the other factors. Additionally, we hypothesize that traits measured during early life including personality and biomarkers of stress resilience and cognitive function, will identify calves that will be resilient to their environment resulting in better performance as a mature dairy cow.
Project Methods
Methods.Facilities. All procedures for the proposed research will be approved by the Institutional Animal Care and Use Committee (IACUC) at the University of Vermont (UVM) and The University of WisconsinRiver Falls (UWRF). There will be two experiments in this project.Objectives 1 and 2 will be conducted in Years 1 to 4, using the same calves enrolled in a large longterm study. UVM will source all calves from a commercial partner dairy that supplies all calves to the Calf Research Center. At the farm of birth, calves will receive maternal colostrum and a blood test for serum total protein (STP) at two days of age. Calves will be eligible for enrollment if they meet the inclusion criteria of successful transfer of passive immunity (STP of ≥ 5.2 g/dL) and weigh between 32 to 55 kg. Enrolled calves will be transported once per week to the UVM Paul Miller Research Center. Based on the number of milking and dry cows at 2,200 dairy cows, it is expected that 23 heifer calves will be born per week. Thus, calf pickup will occur to enroll calves until the number of required animals are present (see below for sample sizes). All heifers will be returned to the commercial dairy at 210 d of gestation where they will be followed until unenrollment based on specific objective requirements.Study Design. Upon arrival to the UVM Research facilities, calves will be pseudo-randomly (balanced for arrival weight and BRIX% for passive transfer) enrolled into one of three treatments that will be administered for 80d:Enhanced nutrition and welfare treatment: high plane of nutrition (3.5 L milk replacer 3 times/day, transition milk until 14 d of life, and high value additives), pair housing, provision of enrichment items (stationary brush and rope), and positive human-animal contact.Enhanced nutrition only: high plane of nutrition (3.5 L milk replacer 3 times/day, transition milk until 14 d of life, and high value additives), individual housing, no enrichment items, and neutral human-animal management.Conventional treatment: modest plane of nutrition (3.5 L milk 2 times/day) no transition milk will be offered, individual housing, no enrichment items, and neutral human-animal management.Management aspects have been compounded into treatments to conserve power, reflect current management systems utilized (conventional), and determine if a system with enhanced practices could alleviate consequences of adverse welfare practices. Enhanced treatments were designed based on the calf management literature. Feeding more milk was shown to increase weight gain and decrease signs of hunger when comparing diets of 6L, 8L, 10L, and 12L per day (Rosenberger et al., 2017). We chose to feed 10.5 L/d to be consistent with the volume of daily calf milk intake when milk was offered ad libitum. Pair housing was chosen in treatment one over group housing to reduce the number of animals enrolled and due to the lack of significant difference in performance in a reversal learning task between group and pair housed calves and other metrics of cognitive development (Meagher et al., 2015). Additionally, pair housing has been shown to increase calf starter intake and average daily gain when compared to individually housed calves (Costa et al., 2015). Provisions of enrichment objects (stationary brush and rope) were chosen based on the decreased anticipatory behaviors expressed in calves provided these enrichment items versus not, which is indicative of an improved affective state (Neave et al., 2021). The conventional treatment was chosen based on predominant calf management practices within the U.S. according to the USDA (2016, 2018).Treatment conditions will be applied from enrollment until two weeks after weaning. At this time all animals will receive the same management according to the UVM Dairy Research Station Protocol. Heifers will be cared for according to the commercial farm management protocols after they are returned to their farm of birth. Thus, differences seen in behavioral expression between treatment groups should be related to early life experiences during the pre-weaning and weaning period.Objective 1: To evaluate the impact of conventional and enhanced early-life management environments (social, nutritional, sensory, and emotional enrichments) on long-term positive behavioral and affective animal welfare indicators, and performance and longevity at various life stages.Hypothesis for Objective 1: We predict that personality trait expression will differ between the enhanced and conventional treatments, and these differences will also be detected in adult cows. We expect that nutritional, social and cognitive enhancements will have additive positive effects on the variables of interest, these animals will be more curious and exploratory, will show a positive judgement bias (reflecting positive emotional state), and will have improved performance and longevity, compared to enhanced nutrition only and conventional calves. Compared to conventional calves, we expect the enhanced nutrition only treatment to positively affect performance and longevity.Objective 2: To evaluate the impact of conventional and enhanced early-life management environments on calf resilience indicated by long-term physiological and neural biomarkers of stress resilience, and relationship between these biomarkers with performance and longevity.Hypothesis for Objective 2: Calves in the enhanced nutrition and welfare treatment will have the longest telomere length, and greatest expression of BDNF, while enhanced nutrition only treatment will be intermediate to the conventional and enhanced nutrition and welfare treatments. These indicators of improved physiological and neural biomarkers of stress resilience will be associated with increased performance and longevity for calves from the enhanced nutrition and welfare treatment.Objective 3: To identify key personality, behavioral, and physiological markers measured during the preweaning period that are associated with resilience and longevity from birth through the first lactation.Objective 3 hypothesis: We expect that curious and exploratory personality traits, greater relative feed intake, longer telomere length, and greater BDNF expression than other calves during the preweaning period will be indicative of calves that are resilient to stressors. Additionally, we anticipate that highresilience calves will have greater longevity (longer herd and productive life) and better performance outcomes (higher weight gain and milk production) than low-resilience calves.