Feed is the largest expense for dairy farms, thus feed efficiency is essential to the sustainability and future of the industry. Our objective was to evaluate the association of milking collar activity with feed intake and health status in lactating cows. Health status was classified for impact of three durations of time (overall, current, or post diagnosis) and as: healthy, mastitis, lame, multiple, or other. Activity data for 155 lactating cows with feed intake records were averaged across two-hour windows to obtain a daily two-hour average. A larger population (n > 1,600) was used to filter out sensor failures and normalize data. Sensor data were adjusted for parity and contemporary group creating adjusted sensor measure (ASM). Dry matter intake (DMI) was adjusted (aDMI) for metabolic body weight, days in milk, and energy sinks used to calculate residual feed intake. Associations between ASM and aDMI, DMI, or health were conducted in SAS9.4. An association of ASM with aDMI was identified (estimate = 0.1635 kg/log count of average activity in a 2-hour period; P < 0.0029). ASM was also associated with DMI (0.2329 kg/log count of average activity, P < 0.0007). ASM was associated with current and overall health timeframes (P < 0.0008 and P < 0.0001, respectively). When health, ASM, and their interaction were included in a model with the response variable aDMI, significant associations were found in the models, including current and overall health (current health: ASM and health: P < 0.0001, interaction: P < 0.0009; overall health: ASM, health, and interaction: P < 0.0001). These results indicate that milking collar data may be useful as a predictor of feed intake either directly or indirectly through detection of health events. Additional studies are needed to determine the predictive ability of collar activity data and the relationship between collar data and health, and to assess if collar activity is an environmental proxy or heritable trait.

Xylose is a primary component of arabinoxylan in swine diets. As arabinoxylan is a significant component of fiber, and fiber is generally rising in practical pig diets globally, the study of arabinoxylan and xylose is of increasing interest. However, the mechanisms by which free xylose may be absorbed and the pathways impacted by xylose have yet to be elucidated in pigs. The objective of this study was to determine the impact of xylose supplementation on gene expression and protein abundance in jejunum, kidney, liver, and muscle tissues which have previously been identified as possible sites of xylose absorption or metabolism. This study aimed to expand the preliminary understanding of dietary xylose metabolism and utilization in pigs. One study, replicated twice with 24 crossbred gilts, was used to assess two dietary treatments: a xylose-free (0%) control and 8% D-xylose. The impact of xylose on growth was monitored by measuring initial and final body weight, serum IGF-1, and liver glycogen concentrations. The rate and efficiency of weight gain were reduced on the xylose diet but not to a level that would occur if xylose was not used at all; the detection of xylose systemically further supports this conclusion. This study confirmed that pigs can utilize dietary xylose. To determine the impact of xylose on tissue metabolism, samples were collected from all four tissues for gene expression analysis by RNA-sequencing, and kidney and liver samples were subjected to proteomic analysis using 2D-DIGE and mass spectrometry. The majority of differentially expressed (DE) genes were identified in the kidney samples (n = 157), with a few identified in the jejunum (n = 16), liver (n = 1), and muscle (n = 20) samples. The DE genes in the kidney were mainly identified as being involved in lipid biosynthesis and fatty acid metabolism. Proteomic results corroborated these findings. Although the inclusion of xylose in a diet at practical levels is shown to impact energy metabolic processes, it has been confirmed that this five-carbon sugar can support levels of growth only slightly below those of glucose, a six-carbon sugar that is more commonly utilized as an energy source in pig diets.