Ractopamine HCl improved cardiac hypertrophy but not poor growth, metabolic inefficiency, or greater white blood cells associated with heat stress in concentrate-fed lambs

Heat stress decreases livestock performance and well-being (Hahn, 1999; Nienaber and Hahn, 2007), causes metabolic dysfunction that decreases growth efficiency (O’Brien et al., 2010), and alters cardiovascular function (Crandall et al., 2008). Each year, heat stress costs the livestock industry up to $2.5 billion (St-Pierre et al., 2003). Ractopamine HCl acts as a nutrient repartitioning agent (Beermann, 2002); classified as a β adrenergic agonist (βAA), it shares pharmacological properties with adrenaline (Beermann, 2002). βAA increase muscle mass and decreases fat deposition through unknown mechanisms (Beermann, 2002). In feedlot cattle, they increase growth efficiency and improve carcass yield and merit (Scramlin et al., 2010; Buntyn et al., 2017), which increases profit and allows more meat to be produced from fewer animals. However, because βAA act via a stress system, it is unclear how the products affect animals under stress conditions. β1AA and β2AA can also cause tachycardia, heart palpitations, and arrhythmias (Sears, 2002). We hypothesize that β1AA combined with heat stress may overstimulate the adrenergic system, resulting is metabolic dysfunction and decreased performance. Sheep are a common model for cattle, and thus, the objective of this study was to determine the impact of ractopamine HCl on health and cardiovascular parameters, growth, and metabolic efficiency in feeder lambs

Identifying Early-Life Behavior to Predict Mothering Ability in Swine Utilizing NU\u3ci\u3etrack\u3c/i\u3e System

Early indicator traits for swine reproduction and longevity support economical selection decision-making. Activity is a key variable impacting a sow’s herd life and productivity. Early-life activities could contribute to farrowing traits including gestation length (GL), number born alive (NBA), and number weaned (NW). Beginning at 20 weeks of age, 480 gilts were video recorded for 7 consecutive days and processed using the NUtrack system. Activity traits included angle rotated (radians), average speed (m/s), distance traveled (m), time spent eating (s), lying lateral (s), lying sternal (s), standing (s), and sitting (s). Final daily activity values were averaged across the period under cameras. Parity one data were collected for all gilts considered. Data were analyzed using linear regression models (R version 4.0.2). GL was significantly impacted by angle rotated (p = 0.03), average speed (p = 0.07), distance traveled (p = 0.05), time spent lying lateral (p = 0.003), and lying sternal (0.02). NBA was significantly impacted by time spent lying lateral (p = 0.01), lying sternal (p = 0.07), and time spent sitting (p = 0.08). NW was significantly impacted by time spent eating (p = 0.09), time spent lying lateral (p = 0.04), and time spent sitting (p = 0.007). This analysis suggests early-life gilt activities are associated with sow productivity traits of importance. Further examination of the link between behaviors compiled utilizing NUtrack and reproductive traits is necessitated to further isolate behavioral differences for potential use in selection decisions

Tracking Bacteria through the Entire Gastrointestinal Tract of a Beef Steer

Biological processes within beef cattle gastrointestinal tracts (GIT) influence animal health, and the output (feces) is an important vector for zoonotic pathogens and antibiotic resistant bacteria. Historically, outside of the rumen, little attention was paid to the bacteria along the GIT, despite their essential role in catabolizing feed into feces. Here we characterize bacteria from 15 GIT sites within a beef steer and examine the proportion of bacteria contributed by upstream compartments. This animal displayed characteristic differences between tissue and digesta communities in gastric and large-intestine, but not small-intestine, samples. The GIT sites shared between 50 and 80% of the operational taxonomic units (OTUs) with their neighboring upstream compartment, with the exception of the ileum. The ileum shared only 11% with the jejunum but displayed a similar phylum-level taxonomic distribution with the jejunum. It is unclear whether the observed changes between compartments represent a nonrandom decrease in bacterial number or rapid multiplication of certain taxa

Body composition estimated by bioelectrical impedance analyses is diminished by prenatal stress in neonatal lambs and by heat stress in feedlot wethers

Body composition correlates to carcass value in livestock, which makes the ability to accurately estimate body composition in the live animal beneficial (Berg and Marchello, 1994). Bioelectrical impedance analysis (BIA) is a clinical tool used to assess body composition in humans (Lukaski et al., 1985), but its use in livestock has been minimal. Lean and fat content contribute to profitability for livestock producers, and poor body composition can be caused by stress that occurs either during in utero development (De Blasio et al., 2007) or during postnatal growth (Boyd et al., 2015). Maternal hyperthermia-induced placental insufficiency (Brown et al., 2015) and sustained maternal inflammation (Cadaret et al., 2018) are two established causes of intrauterine growth restriction (IUGR). IUGR-born animals are characterized by asymmetrical growth restriction that alters lifelong body composition due to impaired muscle growth capacity (Yates et al., 2018). In addition, acute heat stress during periods of peak postnatal growth can alter body composition in livestock (Boyd et al., 2015). We postulate that BIA can detect these changes in the live animal. Thus, the objective of this study was to determine whether BIA measurements can predict changes to body composition in live neonatal lambs exposed to intrauterine stress and in heat-stressed feedlot lambs

Multi-Pig Part Detection and Association with a Fully-Convolutional Network

Computer vision systems have the potential to provide automated, non-invasive monitoring of livestock animals, however, the lack of public datasets with well-defined targets and evaluation metrics presents a significant challenge for researchers. Consequently, existing solutions often focus on achieving task-specific objectives using relatively small, private datasets. This work introduces a new dataset and method for instance-level detection of multiple pigs in group-housed environments. The method uses a single fully-convolutional neural network to detect the location and orientation of each animal, where both body part locations and pairwise associations are represented in the image space. Accompanying this method is a new dataset containing 2000 annotated images with 24,842 individually annotated pigs from 17 different locations. The proposed method achieves over 99% precision and over 96% recall when detecting pigs in environments previously seen by the network during training. To evaluate the robustness of the trained network, it is also tested on environments and lighting conditions unseen in the training set, where it achieves 91% precision and 67% recall. The dataset is publicly available for download

Use of a Novel Oleaginous Microorganism As a Potential Source of Lipids For Weanling Pigs

Weanling pigs are at risk of succumbing to illness due to an immature immune system and insufficient supply of available energy at the time of weaning. This study was aimed at determining whether oleaginous bacteria could serve as a source of lipids to weanling pigs. Weanling pigs were provided a daily dose of 1×109 colony fomring unit (CFU) = kg−1 of the novel oleaginous Enterobacter cloacae strain JD6301 or JD8715 (which is a variant form of JD6301 capable of producing extracellular triglycerides) via oral gavage for 5 d. Serum was collected every 6 h and intestinal samples were collected at 6 d. Providing pigs with JD6301 or JD8715 significantly increased serum concentrations of triglycerides and non-esterified fatty acids (NEFA) within 72 h. Additionally, the JD6301 and JD8715 strains were able to survive within the gastrointestinal tract throughout the duration of the study. These results suggest that providing Enterobacter cloacae can increase the serum lipids in the pigs, thus potentially providing an additional source of energy to animals during times of stress. This could potentially help improve the metabolic response of animals during times of stress

Investigation of the skeletal muscle transcriptome in lambs fed β adrenergic agonists and subjected to heat stress for 21 d

Dietary β-adrenergic agonists (β-AA) are used in livestock to increase muscle protein accretion and decrease adipose deposition during the last 20 to 40 d of the finishing period (Johnson et al., 2014). These β-AA act through specific seven transmembrane receptors and are classified by the receptor isoform to which they primarily bind (Mersmann, 1998). Two β-AA are approved for use in beef cattle in the United States: ractopamine HCl (RAC, β1 agonist) and zilpaterol HCl (ZH, β2 agonist) (Johnson et al., 2014). Supplementation of β-AA increases efficiency of the animal and results in a leaner carcass (Elam et al., 2009). However, the skeletal muscle’s genomic response to these treatments is not well understood. Heat stress (HS) has long been a major concern in the livestock industry. HS occurs when an animal’s body temperature rises above its thermoneutral zone, at which point the heat load exceeds the animal’s capacity for heat dissipation (Bernabucci et al., 2010), resulting in decreased feed intake and poor performance (Marai et al., 2007). Therefore, growth and production decrease during HS, affecting economically important carcass and reproductive traits. As a result, millions of dollars are lost each year due to HS (Renaudeau et al., 2012). Individually, HS and β-AA supplementation have antagonistic effects on muscle growth. However, there is a gap in understanding of the genomic mechanisms through which animals respond to these factors individually and in concert. The purpose of this study is to investigate the effects of β-AA, HS, and their interaction in skeletal muscle using transcriptomic analyses

Fatty Acid Composition of Beef Fed OmniGen- AF at Receiving or Finishing

Beef fatty acid profiles and superoxide dismutase activity were determined for cattle receiving OmniGen- AF supplementation (a patented nutritional supplement) at receiving (first 28 d at the feedlot) or throughout finishing (all 210 d of finishing) vs. a control group (non- supplemented). Th e most meaningful change in fatty acid composition from inclusion of OmniGen- AF was total poly- unsaturated fatty acid (PUFA) content where beef from the finishing group had more PUFA content in relation to the receiving group and was not different from the control group. Despite this increase in PUFA, cattle supplemented through finishing tended to have less lipid oxidation than the other two treatments yet this difference could not be explained by the superoxide dismutase activity

Deficits in growth, muscle mass, and body composition following placental insufficiency-induced intrauterine growth restriction persisted in lambs at 60 d of age but were improved by daily clenbuterol supplementation

Low birthweight in livestock results from stress-induced intrauterine growth restriction (IUGR; Yates et al., 2018). IUGR fetuses exhibit diminished muscle growth that persists in the neonatal stage, leading to asymmetric body composition and decreased weight gain (Cadaret et al., 2019). Ultimately, low birthweight diminishes yield and carcass merit at harvest (Greenwood et al., 2000), making effective postnatal treatment strategies to improve IUGR growth outcomes necessary. In this study, we examined the benefits of injecting the β2 agonist clenbuterol daily to target adrenergic adaptations that we previously observed in IUGR muscle (Posont et al., 2018; Yates et al., 2018). We hypothesized that IUGRinduced growth deficits would persist at the juvenile stage, manifesting in inferior body composition and carcass traits. We also postulated that clenbuterol would at least partially recover growth and body symmetry. Our objective was to test this hypothesis by assessing growth metrics and body composition in IUGR-born lambs hand-reared to 60 d of age and supplemented daily with injectable clenbuterol

Beef cows with atypical estrous cyclicity at puberty produced calves with deficits in preweaning muscling, metabolic indicators, and myoblast function but not in feedlot performance

In cattle, age at puberty and number of estrous cycles prior to first breeding contribute to lifetime reproductive success (Perry et al., 1991). In our university beef herd, we have identified a subset of cows that exhibited irregular pubertal cyclicity patterns between weaning and their first breeding season, which we postulate is associated with high androstenedione in follicular fluid (Cupp et al., 2019). Cows with high androstenedione are subfertile but wean calves that average 17 kg heavier than the herd average (Summers et al., 2014). We hypothesized that this additional weight at weaning in their offspring is due to superior muscling and growth efficiency, characterized by better myoblast function, lean mass, and metabolic efficiency. The objective of this study was to test this hypothesis by evaluating growth and metabolic parameters in calves prior to weaning and in the feedlot, as well as carcass characteristics at harvest. We compared calves from cows that were classified as having typical pubertal cyclicity, start–stop pubertal cyclicity, or noncyclic puberty