Infectious diseases, particularly bovine respiratory disease (BRD) and neonatal calf diarrhea (NCD), are prevalent in calves. Efficient health-monitoring tools to identify such diseases on time are lacking. Common practice (i.e., health checks) often identifies sick calves at a late stage of disease or not at all. Sensor technology enables the automatic and continuous monitoring of calf physiology or behavior, potentially offering timely and precise detection of sick calves. A systematic overview of automated disease detection in calves is still lacking. The objectives of this literature review were hence: to investigate previously applied sensor validation methods used in the context of calf health, to identify sensors used on calves, the parameters these sensors monitor, and the statistical tools applied to identify diseases, to explore potential research gaps and to point to future research opportunities. To achieve these objectives, systematic literature searches were conducted. We defined four stages in the development of health-monitoring systems: (1) sensor technique, (2) data interpretation, (3) information integration, and (4) decision support. Fifty-four articles were included (stage one: 26; stage two: 19; stage three: 9; and stage four: 0). Common parameters that assess the performance of these systems are sensitivity, specificity, accuracy, precision, and negative predictive value. Gold standards that typically assess these parameters include manual measurement and manual health-assessment protocols. At stage one, automatic feeding stations, accelerometers, infrared thermography cameras, microphones, and 3-D cameras are accurate in screening behavior and physiology in calves. At stage two, changes in feeding behaviors, lying, activity, or body temperature corresponded to changes in health status, and point to health issues earlier than manual health checks. At stage three, accelerometers, thermometers, and automatic feeding stations have been integrated into one system that was shown to be able to successfully detect diseases in calves, including BRD and NCD. We discuss these findings, look into potentials at stage four, and touch upon the topic of resilience, whereby health-monitoring system might be used to detect low resilience (i.e., prone to disease but clinically healthy calves), promoting further improvements in calf health and welfare.

In this study, we tested the effects of Yucca schidigera extract (YSE) on the growth performance in broilers, and furthermore, its effects on antioxidative enzyme activities and corresponding gene in the liver of broilers. A total of 128 14-day-old broiler chickens were randomly assigned to four treatments: maize-soybean meal as the basal control diet and the basal diet containing 100, 200, or 300 mg/kg of YSE, respectively, in this study. Each treatment was consisted of four replicate pens with eight broilers per pen. The experiment lasted 28 days. Average daily gain (ADG), average feed intake (AFI) and feed efficiency (FE) were recorded during grower period (d 15 to d 28) and finisher period (d 29 to d 42), respectively. On day 28 and 42, liver samples were collected to analyse superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activities, malondialdehyde (MDA) concentrations, total antioxidant capacity (T-AOC), and gene expressions of SOD, CAT, GPx. The results showed that during grower period, there was no difference on growth performance, while CAT activity and its gene expression were increased at 200 mg/kg YSE level. During finisher period, 100 mg/kg YSE supplementation enhanced ADG, and 100 and 200 mg/kg YSE groups improved FE. T-AOC was improved at both 200 and 300 mg/kg. 300 mg/kg supplementation of YSE enhanced GPx and SOD activity, and decreased MDA concentration. GPx gene expression was up-regulated at 300 mg/kg level. In conclusion, YSE promoted growth performance in broilers as well as exhibited liver antioxidative ability during finisher period.

This study investigated the effects of Artemisia argyi extract (AAE) on broilers challenged with lipopolysaccharide (LPS). A total of 96 Arbour Acres broilers (1-d-old) were assigned to a 2 × 2 factorial arrangement with two dietary treatments (AAE at 0 or 1000 mg/kg) and two immunological challenge treatments (saline or LPS). On d 14, 16, 18 and 20, the broilers were injected intra-abdominally with LPS solution at 500 μg/kg of body weight or an equivalent amount of sterile saline. Blood, liver, spleen and small intestine were collected on day 21. The increased relative weights of the thymus and spleen induced by LPS were significantly decreased by AAE supplementation. The level of serum nitric oxide (NO) and the activity of inducible NO synthase (iNOS) were significantly compromised by AAE inclusion. Dietary AAE significantly inhibited the mRNA expression of toll-like receptor 4 (TLR4), myeloid differentiation factor 88, nuclear factor-kappa B (NF-κB) and iNOS in the different tissues of LPS-challenged broilers. The AAE supplementation tended to increase the levels of serum GSH-Px and CAT, but significantly reduced the level of serum malondialdehyde (MDA). Collectively, feeding AAE to LPS-challenged broilers could decrease serum NO level, maintain the relative weight of internal organs, enhance the antioxidant capacity, and inhibit TLR4/NF-κB signalling pathway at the transcriptional level.