Noninvasive Measures of Stress and Lameness in Broilers

The concept of broiler chicken welfare has evolved from a component of animal husbandry to a label on a chicken product package. Recent attention from the public has led to the need for higher welfare standards for animal production. A primary concern of broiler production is low activity/locomotion attributed to fast growth rates leading to poor leg health. To collect the scientific data necessary to determine conditions providing the best welfare for the bird, multiple methods of assessment are required. Stress is influenced by external (temperature, humidity, lighting, stocking density) and internal (metabolism, thermoregulation, hormonal balance) factors. This series of studies evaluated measures of health, stress and behavior. The main objective was to investigate noninvasive measures of broiler stress and lameness. The two primary noninvasive methods were extraction of the stress hormone corticosterone (CORT) from feathers to evaluate stress and infrared thermography (IRT) to evaluate stress as well as lameness attributed to bacterial chondronecrosis with osteomyelitis (BCO). First, an ELISA was used to measure the effects of CORT administration in the drinking water over a 72 hour period on CORT from serum, cecal contents, excreta and two feather types. The next series of studies evaluated light intensity and flooring type effects on broiler stress and leg health. Results from these studies indicate light intensity did not consistently affect the stress and leg health parameters that were measured. Rearing broilers on wire flooring is an effective method for inducing BCO lameness. While the wire flooring did induce lameness, it did not consistently affect stress or leg health parameters measured on sound broilers. The final study combined stress and lameness measures from previous studies to compare lame and sound broilers. In this study, statistical models were evaluated for their potential use in predicting lameness. The results from these studies suggest 1) the current method of extracting CORT from feathers is not useful to evaluate stress; 2) IRT measures of beak surface temperatures may be a useful method to evaluate stress; and 3) IRT measures of leg region surface temperatures may be a useful method to detect/predict lameness attributed to BCO in broilers

The Cost and Market Impacts of Slow-Growth Broilers

There has been substantial productivity growth in the broiler industry; however, high growth rates might adversely affect animal welfare, resulting in calls for slow-growth breeds. This research shows production costs are 11%'25% per pound higher for slower-growing breeds than for modern breeds, depending on the target endpoint. Breakeven wholesale price premiums needed equate net returns of slow- to fast-growth broilers range from $0.10/lb to$0.36/lb. Annual costs of an industry-wide conversion to slow growth are $450 million for consumers and$3.1 billion for producers. Consumer willingness-to-pay would need to increase 10.8% to offset the producer losses

Image1_Ileal and cecal microbiota response to Salmonella Typhimurium challenge in conventional and slow-growing broilers.pdf

Despite the negative impacts of Salmonella intestinal colonization on human health, Salmonella is a natural colonizer of the gastrointestinal tract and is not overtly pathogenic to the avian host. It is of interest to understand the impacts and colonization rates of Salmonella across selected genetic lines such as slow-growing (SG) and conventional (CONV) broilers. The objective of this study was to characterize the relationship between Salmonella enterica serovar Typhimurium challenge and selected broiler genetic lines on the ileal and cecal microbiome. Male chicks of two broiler breeds (n = 156/breed) were cohoused in an open floor pen until day 7. On day 13, the chicks were then separated into 12 isolators per breed (4 rooms, 6 isolators/room, 11 chicks/isolator). On day 14, chicks in the 12 treatment isolators (6 isolators/breed, 108 total) were challenged with Salmonella Typhimurium (ST) (1 × 108 CFU/ml) via oral gavage while the remaining chicks (n = 108) were given an oral gavage of sterile tryptic soy broth control (C). Ileal and cecal contents were collected on day 7 from 24 chicks of each breed, and on days 13, 17, 21, and 24 from two chicks per isolator. Samples underwent DNA extraction and PCR amplification to obtain 16S rRNA amplicons that were sequenced with Illumina MiSeq. Salmonella Typhimurium colonization in the cecum was not different in the two broiler breeds. The main effect of breed had the greatest impact on the ileum microbiota of broilers 7 days of age where SG broilers had significantly lower diversity and richness compared to CONV broilers (p < 0.05). Salmonella Typhimurium challenge consistently caused a change in beta diversity. Regardless of day or intestinal location, challenged broilers had many amplicon sequence variants (ASVs) with decreased abundance of likely beneficial bacteria such as Mollicutes RF39, Shuttleworthia, Flavonifractor, and Oscillibacter compared to broilers that were unchallenged with Salmonella Typhimurium (p < 0.05). Additionally, there was a difference in the timing of when the microbiota alpha and beta diversity of each breed responded to Salmonella Typhimurium challenge. Thus, both broiler breed and Salmonella Typhimurium can impact the intestinal microbiota.</p

Comparison of nursery pig behavior assessed using human observation and digital-image evaluation methodologies

Objectives: To design and implement a digital photograph system to document the pig response to a human observer in the home pen and then compare these results to a human observation in an approach-assessment paradigm. Materials and methods: An observer entered the nursery pen and crouched down with an outstretched arm for 15 seconds. A digital image was recorded, and the observer counted all pigs touching, oriented, and not oriented to the human. Each digital image was used to determine the snout and tail-base proximity to the index finger of the observer for pigs classified as Touch, Oriented, and Not Oriented when pens were divided into thirds and quarters. Postures and behaviors of pigs classified as Not Oriented were further delineated. Human observation and digital image were compared. Results: Most Not Oriented pigs in the digital image were standing, followed by sitting, with 2.5% piling. Both snout and tail-base proximities were closer for Touch pigs than for the other categories (P \u3c .001). Regardless of how pens were divided, more pigs were located in the section farthest from the observer. There were no differences (P \u3e .05) between human observation and digital-image evaluation for pigs classified as Touch. More pigs were classified as Oriented and fewer as Not Oriented for digital-image evaluation (P \u3c .001). Implication: Human observation is a faster and practical application, but digital-image evaluation allows for more information to be collected