ABSTRACT
Social housing for dairy calves has a range of benefits for social development, yet there is limited understanding of how social bonds form early in life. We characterized effects of early life social contact on the development of social preference for calves varying in familiarity. A total of 40 calves were tested in a social preference test at 4 weeks of age to assess the formation of social bonds and preference for their peers. Within an open-field social preference test, focal calves were presented with two stimulus calves, one 'more familiar' and one 'less familiar'. We found that pair-housed calves spent more time in close proximity with either stimulus calf and had a greater preference for their pen-mate, compared to another calf reared within visual contact. Individually housed calves exhibited no preference for calves reared within visual but not physical contact compared to calves that were completely unfamiliar. Of the calves that approached both stimulus calves, individually housed calves that approached the 'less familiar' calf first spent less time near the 'more familiar' calf, whereas behavior of pair-housed calves was not affected by the first calf approached. These results suggest that physical contact is necessary for the development of social bonds in young dairy calves, and early life social housing may support the development of normal social behavior in dairy cattle.
ABSTRACT
Background: Hypertriglyceridemia is a common condition in the United States and is often associated with other metabolic disturbances, including insulin resistance, metabolic syndrome, and a predominance of small dense LDL particles.Objective: The objective of this trial was to evaluate the effects of a combination of egg protein (Epro) and unsaturated fatty acids (UFAs) substituted for refined starches and added sugars on insulin sensitivity (primary outcome) and other cardiometabolic health markers in overweight or obese adults with elevated triglyceride (TG) concentrations.Methods: Subjects with elevated TG concentrations were given test foods prepared by using Epro powder (â¼8% of energy) and vegetable oil (â¼8% of energy; Epro and UFA condition) or test foods prepared by using refined starch and sugar (â¼16% of energy; carbohydrate condition) in a randomized, double-blind, controlled-feeding, crossover trial (3 wk/condition, 2-wk washout). The Matsuda insulin sensitivity index (MISI), fasting lipids, and other cardiometabolic health markers were assessed at baseline and the end of each diet condition. Responses were compared by using repeated-measures ANCOVA.Results: Twenty-five participants [11 men, 14 women; mean ± SEM: age, 46.3 ± 2.4 y; body mass index (in kg/m2), 31.8 ± 1.0] with a median (interquartile range limits) fasting serum TG concentration of 173 mg/dL (159, 228 mg/dL) completed the trial. The MISI value increased 18.1% ± 8.7% from baseline during the Epro and UFA condition and decreased 5.7% ± 6.2% from baseline during the carbohydrate condition (P < 0.001). The disposition index increased 23.8% ± 20.8% during the Epro and UFA condition compared with a decrease of 16.3% ± 18.8% during carbohydrate (P = 0.042) and LDL peak particle size increased 0.12 nm (-0.12, 0.28 nm) with Epro and UFA compared with a decrease of 0.15 nm (-0.33, 0.12 nm) with carbohydrate (P = 0.019). TG and VLDL cholesterol concentrations were lowered by 18.5% (-35.7%, -6.9%) and 18.6% (-34.8%, -7.4%), respectively, after the Epro and UFA condition and by 2.5% (-13.4%, 17.0%) and 3.6% (-12.5%, 16.2%), respectively, after the carbohydrate diet condition (P < 0.002).Conclusions: The replacement of refined carbohydrates with a combination of Epro and UFA increased the MISI value and altered several markers of cardiometabolic health in overweight or obese adults with elevated TG concentrations. This trial was registered at clinicaltrials.gov as NCT02924558.