Scholarly Works, School of Animal Sciences
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- Effects of Individual Essential Amino Acids on Growth Rates of Young Rats Fed a Low-Protein DietLiu, Wei; Wang, Tianyi; Zhao, Kai; Hanigan, Mark D.; Lin, Xueyan; Hu, Zhiyong; Hou, Qiuling; Wang, Yun; Wang, Zhonghua (MDPI, 2024-03-20)To investigate the effects of individual essential amino acids (EAA) on growth and the underlying mechanisms, EAA individually supplemented a low-protein (LP) diet fed to young rats in the present study. Treatments were an LP diet that contained 6% crude protein (CP), a high-protein (HP) diet that contained 18% CP, and 10 LP diets supplemented with individual EAA to achieve an EAA supply equal to that of the HP diet. The CP concentration of the LP diet was ascertained from the results of the first experiment, which examined the effects of dietary CP concentrations on growth rates, with CP ranging from 2% to 26%. Weight gain was increased with the supplementation of His, Ile, Lys, Thr, or Trp as compared to the LP diet (p < 0.05). Feed intake was greater for the His-, Lys-, and Thr-supplemented treatments as compared to the LP group (p < 0.05). Protein utilization efficiency was lower for the HP group than other groups (p < 0.01). The supplementation of Leu, Lys, and Val led to reduced protein utilization efficiency (p < 0.05), but the supplementation of Thr and Trp led to greater efficiency than the LP group (p < 0.05). Compared to the LP group, plasma urea concentrations were elevated with individual EAA supplementation, with the exception of the Thr addition. The added EAA resulted in increased concentrations of the corresponding EAA in plasma, except for Arg and Phe supplementation. The supplementation of Arg, His, Leu, Lys, and Met individually stimulated mTORC1 pathway activity (p < 0.05), and all EAA resulted in the decreased expression of ATF4 (p < 0.05). In summary, the supplementation of His, Ile, Lys, Thr, or Trp to an LP diet improved the growth performance of young rats. Responses to His and Lys additions were related to the activated mTORC1 pathway and feed intake increases. The improved growth performance resulting from the addition of a single EAA is not solely attributed to the increased plasma availability of EAA. Rather, it may be the consequence of a confluence of factors encompassing signaling pathways, the availability of amino acids, and other associated elements. The additivity of these factors results in independent responses to several EAA with no order of limitation, as is universally encoded in growth models for all production animal species.
- Plasma γ-Aminobutyric Acid (GABA) Concentrations in Lactating Holstein Cows during Thermoneutral and Heat Stress Conditions and Their Relationships with Circulating Glucose, Insulin and Progesterone LevelsArneson, Alicia G.; Stewart, Jacob W.; Byrd, MaryKate H.; Perry, George A.; Rhoads, Michelle L. (MDPI, 2024-03-21)Heat-stressed lactating dairy cattle exhibit unique metabolic symptoms, many of which are undoubtedly involved in heat-induced subfertility. Because of its known systemic effects, we hypothesized that γ-aminobutyric acid (GABA) participates in the regulation of insulin and progesterone during heat stress. Multiparous lactating Holstein cows (n = 6) were studied during four experimental periods: (1) thermoneutral (TN; d 1–5), (2) TN + hyperinsulinemic–hypoglycemic clamp (d 6–10), (3) heat stress (HS; d 16–20), and (4) HS + euglycemic clamp (d 21–25). Blood samples were collected once daily via coccygeal venipuncture into heparinized evacuated tubes. Analysis of GABA concentrations from all four treatment periods yielded no differences. In direct comparison to TN concentrations, plasma GABA tended to decrease during the HS period (16.57 ± 2.64 vs. 13.87 ± 2.28 ng/mL, respectively, p = 0.06). Both milk production and plasma insulin were moderately correlated with plasma GABA (r = 0.35, p < 0.01; r = −0.32, p < 0.01). Plasma progesterone was correlated with plasma GABA concentrations during TN but not HS periods. These results are the first to indicate that peripheral GABA could be involved in the regulation of factors known to affect production and reproduction during heat stress. More research is needed to determine its precise role(s).
- Chromatin profiling reveals TFAP4 as a critical transcriptional regulator of bovine satellite cell differentiationLyu, Pengcheng; Jiang, Honglin (2024-03-12)Background: Satellite cells are myogenic precursor cells in adult skeletal muscle and play a crucial role in skeletal muscle regeneration, maintenance, and growth. Like embryonic myoblasts, satellite cells have the ability to proliferate, differentiate, and fuse to form multinucleated myofibers. In this study, we aimed to identify additional transcription factors that control gene expression during bovine satellite cell proliferation and differentiation. Results: Using chromatin immunoprecipitation followed by sequencing, we identified 56,973 and 54,470 genomic regions marked with both the histone modifications H3K4me1 and H3K27ac, which were considered active enhancers, and 50,956 and 59,174 genomic regions marked with H3K27me3, which were considered repressed enhancers, in proliferating and differentiating bovine satellite cells, respectively. In addition, we identified 1,216 and 1,171 super-enhancers in proliferating and differentiating bovine satellite cells, respectively. Analyzing these enhancers showed that in proliferating bovine satellite cells, active enhancers were associated with genes stimulating cell proliferation or inhibiting myoblast differentiation whereas repressed enhancers were associated with genes essential for myoblast differentiation, and that in differentiating satellite cells, active enhancers were associated with genes essential for myoblast differentiation or muscle contraction whereas repressed enhancers were associated with genes stimulating cell proliferation or inhibiting myoblast differentiation. Active enhancers in proliferating bovine satellite cells were enriched with binding sites for many transcription factors such as MYF5 and the AP-1 family transcription factors; active enhancers in differentiating bovine satellite cells were enriched with binding sites for many transcription factors such as MYOG and TFAP4; and repressed enhancers in both proliferating and differentiating bovine satellite cells were enriched with binding sites for NF-kB, ZEB-1, and several other transcription factors. The role of TFAP4 in satellite cell or myoblast differentiation was previously unknown, and through gene knockdown and overexpression, we experimentally validated a critical role for TFAP4 in the differentiation and fusion of bovine satellite cells into myofibers. Conclusions: Satellite cell proliferation and differentiation are controlled by many transcription factors such as AP-1, TFAP4, NF-kB, and ZEB-1 whose roles in these processes were previously unknown in addition to those transcription factors such as MYF5 and MYOG whose roles in these processes are widely known.
- Molecular and Cellular Mechanisms of Intramuscular Fat Development and Growth in CattleTan, Zhendong; Jiang, Honglin (MDPI, 2024-02-21)Intramuscular fat, also referred to as marbling fat, is the white fat deposited within skeletal muscle tissue. The content of intramuscular fat in the skeletal muscle, particularly the longissimus dorsi muscle, of cattle is a critical determinant of beef quality and value. In this review, we summarize the process of intramuscular fat development and growth, the factors that affect this process, and the molecular and epigenetic mechanisms that mediate this process in cattle. Compared to other species, cattle have a remarkable ability to accumulate intramuscular fat, partly attributed to the abundance of sources of fatty acids for synthesizing triglycerides. Compared to other adipose depots such as subcutaneous fat, intramuscular fat develops later and grows more slowly. The commitment and differentiation of adipose precursor cells into adipocytes as well as the maturation of adipocytes are crucial steps in intramuscular fat development and growth in cattle. Each of these steps is controlled by various factors, underscoring the complexity of the regulatory network governing adipogenesis in the skeletal muscle. These factors include genetics, epigenetics, nutrition (including maternal nutrition), rumen microbiome, vitamins, hormones, weaning age, slaughter age, slaughter weight, and stress. Many of these factors seem to affect intramuscular fat deposition through the transcriptional or epigenetic regulation of genes directly involved in the development and growth of intramuscular fat. A better understanding of the molecular and cellular mechanisms by which intramuscular fat develops and grows in cattle will help us develop more effective strategies to optimize intramuscular fat deposition in cattle, thereby maximizing the quality and value of beef meat.
- A meta-analysis of the relationship between milk protein production and absorbed amino acids and digested energy in dairy cattleMark Hanigan; Vinícius Carneiro de Souza; Roger Martineuau; Hélène Lapierre; Xin Feng; Veridiana Daley (Journal of Dairy Science)Supplemental materials of the paper "A meta-analysis of the relationship between milk protein production and absorbed amino acids and digested energy in dairy cattle".
- Fetal Programming and Its Effects on Meat Quality of Nellore BullsChristofaro Fernandes, Arícia; Beline, Mariane; Polizel, Guilherme Henrique Gebim; Cavalcante Cracco, Roberta; Ferreira Dias, Evandro Fernando; Furlan, Édison; da Luz e Silva, Saulo; de Almeida Santana, Miguel Henrique (MDPI, 2023-11-24)This work aimed to evaluate the effects of prenatal nutritional stimulation at different pregnancy stages on carcass traits and meat quality in bovine progeny. For this purpose, 63 Nellore bulls, born from cows submitted to three nutritional plans, were used: not programmed (NP), which did not receive protein supplementation; partially programmed (PP), which had protein-energy supplementation (0.3% of mean body weight of each batch) only in the final third of pregnancy; and full programming (FP), which received supplementation (0.3% of mean body weight of each batch) throughout pregnancy. The averages of parameters were submitted to the ANOVA, and the supplementation periods, which were different when p value < 0.05, were compared. Carcass weights and rib eye area (REA) did not differ between treatments (p > 0.05), but subcutaneous fat thickness (SFT) showed a tendency (p = 0.08) between groups. For lipids and marbling, no differences were found (p > 0.05). In the analyses of maturation time and shelf life, no difference was observed between treatments. However, there was a tendency between treatments at 14 days of maturation time for cooking loss (CL) (p = 0.08). Treatments did not affect shear force in the progenies (p > 0.05). Fetal programming had no effect on the meat quality of Nellore bulls.
- Farm-Scale Effectiveness of Feed Additives Supplied through a Mineral Mix for Beef Cattle Grazing Tropical PasturesGoulart, Ricardo Cazerta Duarte; Costa, Diogo Fleury Azevedo; Silva, Tiago Alves Corrêa Carvalho da; Congio, Guilhermo Francklin de Souza; Marques, Rodrigo da Silva; Corsi, Moacyr (MDPI, 2023-12-13)The effectiveness of feed additives delivered through free-choice mineral mixtures (MMs) to grazing cattle remains unclear. Two farm-scale and one in vitro experiment (Exp.) were conducted to investigate the effects of salinomycin and virginiamycin, delivered through an MM, on growing bulls grazing tropical pastures. In Exp. 1, 316 zebu (Bos indicus) Nellore bulls (225 ± 26.7 kg liveweight (LW)) were randomly allocated to four treatments: (1) MM no additives (CON), (2) MM with salinomycin at 1950 mg/kg (SLI), (3) MM with salinomycin at 780 mg/kg (SHI), and (4) MM with virginiamycin at 1950 mg/kg (VGN). Over 123 days, these bulls grazed tropical grasses on pastures of guinea grass, palisade grass, or Bermuda grass. No significant treatment effects were observed for oocyst eggs or ruminal parameters. Bulls fed VGN had higher average daily gain (ADG) compared to CON (p = 0.02) and SLI (p = 0.03) but similar compared to SHI (p = 0.07). In Exp. 2, 308 zebu cross bulls (237 ± 23.0 kg LW) grazed Bermuda grass paddocks and were allocated into two treatments: (1) MM with no additives (CON) and (2) MM containing virginiamycin at 2522 mg/kg (VGN). Cattle fed VGN had a significantly higher ADG (p = 0.007). Exp. 3 tested salinomycin’s effectiveness in vitro at different exposure times to MM, revealing no impact of exposure time on short-chain fatty acid production. In conclusion, virginiamycin delivered through free-choice MM can increase grazing beef bulls’ ADG by 12% compared with CON, with no clear link to rumen fermentation or coccidiostat effects.
- Influences of Supplementing Selective Members of the Interleukin-6 Cytokine Family on Bovine Oocyte CompetencyMcKinley, Endya; Speckhart, Savannah L.; Keane, Jessica A.; Oliver, Mary A.; Rhoads, Michelle L.; Edwards, J. Lannett; Biase, Fernando H.; Ealy, Alan D. (MDPI, 2023-12-21)This work explored whether supplementing selective members of the interleukin-6 (IL6) cytokine family during in vitro bovine oocyte maturation affects maturation success, cumulus–oocyte complex (COC) gene expression, fertilization success, and embryo development potential. Human recombinant proteins for IL6, IL11, and leukemia inhibitory factor (LIF) were supplemented to COCs during the maturation period, then fertilization and embryo culture commenced without further cytokine supplementation. The first study determined that none of these cytokines influenced the rate that oocytes achieved arrest at meiosis II. The second study identified that LIF and IL11 supplementation increases AREG transcript abundance. Supplementation with IL6 supplementation did not affect AREG abundance but reduced HAS2 transcript abundance. Several other transcriptional markers of oocyte competency were not affected by any of the cytokines. The third study determined that supplementing these cytokines during maturation did not influence fertilization success, but either LIF or IL11 supplementation increased blastocyst development. No effect of IL6 supplementation on subsequent blastocyst development was detected. The fourth experiment explored whether each cytokine treatment affects the post-thaw survivability of cryopreserved IVP blastocysts. None of the cytokines supplemented during oocyte maturation produced any positive effects on post-thaw blastocyst re-expansion and hatching. In conclusion, these outcomes implicate IL11 and LIF as potentially useful supplements for improving bovine oocyte competency.
- An Overview of Reactive Oxygen Species Damage Occurring during In Vitro Bovine Oocyte and Embryo Development and the Efficacy of Antioxidant Use to Limit These Adverse EffectsKeane, Jessica A.; Ealy, Alan D. (MDPI, 2024-01-21)The in vitro production (IVP) of bovine embryos has gained popularity worldwide and in recent years and its use for producing embryos from genetically elite heifers and cows has surpassed the use of conventional superovulation-based embryo production schemes. There are, however, several issues with the IVP of embryos that remain unresolved. One limitation of special concern is the low efficiency of the IVP of embryos. Exposure to reactive oxygen species (ROS) is one reason why the production of embryos with IVP is diminished. These highly reactive molecules are generated in small amounts through normal cellular metabolism, but their abundances increase in embryo culture because of oocyte and embryo exposure to temperature fluctuations, light exposure, pH changes, atmospheric oxygen tension, suboptimal culture media formulations, and cryopreservation. When uncontrolled, ROS produce detrimental effects on the structure and function of genomic and mitochondrial DNA, alter DNA methylation, increase lipid membrane damage, and modify protein activity. Several intrinsic enzymatic pathways control ROS abundance and damage, and antioxidants react with and reduce the reactive potential of ROS. This review will focus on exploring the efficiency of supplementing several of these antioxidant molecules on oocyte maturation, sperm viability, fertilization, and embryo culture.
- A Multi-Institutional Description of Processes and Outcomes of Postbaccalaureate Research Education Programs in the Mid-Atlantic RegionWright, Cynthia F.; Kasman, Laura M.; Robinson, Donita L.; Carey, Gregory B.; Hall, Joshua D.; Lloyd, Joyce A.; Shiang, Rita; Smith, Edward J.; Wilson, Katherine L. (American Association of Medical Colleges, 2024-01-13)Outcome data from 6 National Institutes of Health–funded Postbaccalaureate Research Education Programs (PREPs) in the Mid-Atlantic region were combined to give a multi-institutional perspective on their scholars’ characteristics and progress through biomedical research training. The institutions hosting these programs were Johns Hopkins University School of Medicine, the Medical University of South Carolina, the University of Maryland School of Medicine, the University of North Carolina at Chapel Hill, Virginia Commonwealth University, and Virginia Polytechnic Institute and State University. The authors summarize the institutional pathways, demographics, undergraduate institutions, and graduate institutions for a total of 384 PREP scholars who completed the programs by June 2021. A total of 228 (59.3%) of these PREP scholars identified as Black or African American, 116 (30.2%) as Hispanic or Latinx, and 269 (70.0%) as female. The authors found that 376 of 384 scholars (97.9%) who started PREP finished their program, 319 of 376 (84.8%) who finished PREP matriculated into PhD or MD/PhD programs, and 284 of 319 (89.0%) who matriculated have obtained their PhD or are successfully making progress toward their PhD.
- Editorial: Bio-accessibility of functional compounds and nutrients of animal dietsRossi, Luciana; Theodorou, Georgios; Osorio, Johan; Castiglioni, Bianca (Frontiers, 2023-11-16)
- Reducing barking in a Brazilian animal shelter: A practical interventionBaldan, Ana Lucia; Ferreira, Bruna Lima; Warisaia, Vinicius; Feuerbacher, Erica N.; Monticelli, Patricia Ferreira; Gunter, Lisa M. (Elsevier, 2023-08)Barking is a common problem in animal shelters. Loud noise is an irritant and stressful to both humans and other animals. In the present study, we tested a positive reinforcement intervention using food delivery with 70 dogs at a municipal animal shelter in Pirassununga, state of São Paulo, Brazil. The experiment consisted of three conditions with three daily phases: pre-intervention (A1), intervention (B), and post-intervention (A2). The intervention consisted of the experimenter (ALB) entering the building in which dogs were housed, stopping at each of its 12 kennels (between 4 and 6 dogs in each kennel), and delivering food to the dogs after they had ceased barking. After the first study condition with its single experimenter, we conducted two other conditions to test the generalization of the intervention with novel stimuli. In Condition 2, the experimenter was accompanied by a student; and in Condition 3, the experimenter was with the same student and a shelter employee. Continuous sound levels (Leq dB) and duration of barking were measured pre- and post-intervention throughout the study's three conditions as well as the amount of time needed to carry out the intervention each day. We found that, on average, both Leq dB and barking duration reduced following the intervention with a decrease in both measures from the beginning to the end of the study. Furthermore, intervention implementation time shortened across the study's conditions, with less than three minutes needed for the intervention to be carried out in Condition 3. In total, our findings suggest that the Barking Reduction Protocol (BRP) is an effective, low-effort intervention that reduces dog barking in the animal shelter. When considering the many issues that compromise the daily lives of shelter dogs, this intervention may be a useful tool in changing dogs’ barking behavior in response to people and improve their welfare as they await adoption.
- Phosphorylation of RPT6 Controls Its Ability to Bind DNA and Regulate Gene Expression in the Hippocampus of Male Rats during Memory FormationFarrell, Kayla; Auerbach, Aubrey; Musaus, Madeline; Navabpour, Shaghayegh; Liu, Catherine; Lin, Yu; Xie, Hehuang; Jarome, Timothy J. (Society for Neuroscience, 2024-01)Memory formation requires coordinated control of gene expression, protein synthesis, and ubiquitin–proteasome system (UPS)-mediated protein degradation. The catalytic component of the UPS, the 26S proteasome, contains a 20S catalytic core surrounded by two 19S regulatory caps, and phosphorylation of the 19S cap regulatory subunit RPT6 at serine 120 (pRPT6-S120) has been widely implicated in controlling activity-dependent increases in proteasome activity. Recently, RPT6 was also shown to act outside the proteasome where it has a transcription factor-like role in the hippocampus during memory formation. However, little is known about the proteasome-independent function of “free” RPT6 in the brain or during memory formation and whether phosphorylation of S120 is required for this transcriptional control function. Here, we used RNA-sequencing along with novel genetic approaches and biochemical, molecular, and behavioral assays to test the hypothesis that pRPT6-S120 functions independently of the proteasome to bind DNA and regulate gene expression during memory formation. RNA-sequencing following siRNA-mediated knockdown of free RPT6 revealed 46 gene targets in the dorsal hippocampus of male rats following fear conditioning, where RPT6 was involved in transcriptional activation and repression. Through CRISPR-dCas9-mediated artificial placement of RPT6 at a target gene, we found that RPT6 DNA binding alone may be important for altering gene expression following learning. Further, CRISPR-dCas13-mediated conversion of S120 to glycine on RPT6 revealed that phosphorylation at S120 is necessary for RPT6 to bind DNA and properly regulate transcription during memory formation. Together, we reveal a novel function for phosphorylation of RPT6 in controlling gene transcription during memory formation.
- Internet of Things‐Enabled Food and Plant Sensors to Empower SustainabilityAli, Azahar; Ataei Kachouei, Matin; Kaushik, Ajeet (Wiley, 2023-10-10)To promote sustainability, this review explores: 1) the utilization of affordable high-performance sensors that can enhance food safety and quality, plant growth, and disease management and 2) the Internet of Things (IoT)-supported sensors to empower farmers, stakeholders, and agro-food industries via rapid testing and predictive analysis based on sensing generated informatics using artificial intelligence (AI). The performance of such sensors is noticeable, but this technology is still not suitable to be used in real applications owing to the lack of focus, scalability, well-coordinated research, and regulations. To cover this gap, this review carefully and critically analyzes state-of-the-art sensing technologies developed for food quality assurance (i.e., contaminants, toxins, and packaging testing) and plant growth monitoring (i.e., phenotyping, stresses, volatile organic components, nutrient levels, hormones, and pathogens) along with the possible challenges. The following has been proposed for future research: 1) promoting the optimized combination of green sensing units supported by IoT to perform testing at the location, considering the remote and urban areas as a key focus, and 2) analyzing generated informatics via AI should also be a focus for risk assessment understanding and optimizing necessary safety majors. Finally, the perspectives of IoT-enabled sensors, along with their real-world limitations, are discussed.
- Testing for BLV: Control, reduction, and elimination?Ali, Azahar; Corl, Benjamin (Virginia State Dairymen's Association, 2024-10-01)
- Ablation of OCT4 function in cattle embryos by double electroporation of CRISPR-Cas for DNA and RNA targeting (CRISPR-DART)Nix, Jada L.; Schettini, Gustavo P.; Speckhart, Savannah L.; Ealy, Alan D.; Biase, Fernando H. (Oxford University Press, 2023-11-01)CRISPR-Cas ribonucleoproteins (RNPs) are important tools for gene editing in preimplantation embryos. However, the inefficient production of biallelic deletions in cattle zygotes has hindered mechanistic studies of gene function. In addition, the presence of maternal RNAs that support embryo development until embryonic genome activation may cause confounding phenotypes. Here, we aimed to improve the efficiency of biallelic deletions and deplete specific maternal RNAs in cattle zygotes using CRISPR-Cas editing technology. Two electroporation sessions with Cas9D10A RNPs targeting exon 1 and the promoter of OCT4 produced biallelic deletions in 91% of the embryos tested. In most cases, the deletions were longer than 1,000 nucleotides long. Electroporation of Cas13a RNPs prevents the production of the corresponding proteins. We electroporated Cas9D10A RNPs targeting exon 1, including the promoter region, of OCT4 in two sessions with inclusion of Cas13a RNPs targeting OCT4 mRNAs in the second session to ablate OCT4 function in cattle embryos. A lack of OCT4 resulted in embryos arresting development prior to blastocyst formation at a greater proportion (13%) than controls (31.6%, P < 0.001). The few embryos that developed past the morula stage did not form a normal inner cell mass. Transcriptome analysis of single blastocysts, confirmed to lack exon 1 and promoter region of OCT4, revealed a significant (False Discovery Rate, FDR < 0.1) reduction in transcript abundance of many genes functionally connected to stemness, including markers of pluripotency (CADHD1, DPPA4, GNL3, RRM2). The results confirm that OCT4 is a key regulator of genes that modulate pluripotency and is required to form a functional blastocyst in cattle.
- Graduate Student Literature Review: System, plant, and animal factors controlling dietary pasture inclusion and its impact on ration formulation for dairy cowsMorales, A. G.; Cockrum, Rebecca R.; Teixeira, I. A. M. A.; Ferreira, Gonzalo; Hanigan, Mark D. (American Dairy Science Association, 2023-09-26)Diet formulation in a pasture-based dairy system is a challenge as the quality and quantity of available pasture, which generally constitutes the base diet, is constantly changing. The objective of this paper is to cover a more in-depth review of the nutritional characteristics of pasture-based diets, identifying potential system, plant, and animal factors that condition pasture dietary inclusion in dairy cows. In practice, there is a wide diversity of pasture-based systems with predominant to minimal use of pasture requiring a more specific classification that potentially considers the amount and time of access to pasture, access to housing, length of grazing season, seasonality of calving, and level and method of supplementation. There are important differences in the nutritional quality between pasture species and even cultivars. However, under management practices that promote maintenance of pasture in a vegetative state as well as controlling the availability of pasture, it is possible to achieve high DM intakes (∼2.9-3.4% of live weight) of pasture with moderate to high diet energy density, protein supply and digestibility. The amount of pasture to include in the diet will depend on several factors, such as the type of production system, the cost of supplementary feeds, and the farmer's objective, but inclusions of ∼40-50% of the diet seems to potentially reduce costs while apparently not limiting voluntary feed intake. Considering that there seems to be a continuum of intermediate management systems, a better understanding of the factors inherent to the feed ingredients used, as well as the use of nutrients by cows, and potential interactions between animal × system should be addressed in greater depth. This requires a meta-analysis approach, but given the diversity of the pasture-based system in practice, the existing information is highly fragmented. A clear definition of "subsystems" is necessary to direct the future research and development of mechanistic models.
- Predators for Free-Ranging PoultryJacobs, Leonie (2023-09-28)
- Individuality of a group: detailed walking ability analysis of broiler flocks using optical flow approachvan der Eijk, Jerine A. J.; Guzhva, Oleksiy; Schulte-Landwehr, Jan; Giersberg, Mona F.; Jacobs, Leonie; de Jong, Ingrid C. (Elsevier, 2023-10-01)Impaired walking ability is one of the most important factors affecting broiler welfare. Routine monitoring of walking ability provides insights in the welfare status of a flock and assists farmers in taking remedial measures at an early stage. Several computer vision techniques have been developed for automated assessment of walking ability, providing an objective and biosecure alternative to the currently more subjective and time-consuming manual assessment of walking ability. However, these techniques mainly focus on assessment of averages at flock level using pixel movement. Therefore, the aim of this study was to investigate the potential of optical flow algorithms to identify flock activity, distribution and walking ability in a commercial setting on levels close to individual monitoring. We used a combination of chicken segmentation and optical flow methods, where chicken contours were first detected and were then used to identify activity, spatial distribution, and gait score distribution (i.e. walking ability) of the flock via optical flow. This is a step towards focusing more on individual chickens in an image and its pixel representation. In addition, we predicted the gait score distribution of the flock, which is a more detailed assessment of broiler walking ability compared to average gait score of the flock, as slight changes in walking ability are more likely to be detected when using the distribution compared to the average score. We found a strong correlation between predicted and observed gait scores (R2 = 0.97), with separate gait scores all having R2 > 0.85. Thus, the algorithm used in this study is a first step to measure broiler walking ability automatically in a commercial setting on a levels close to individual monitoring. These validation results of the developed automatic monitoring of flock activity, distribution and gait score are promising, but further validation is required (e.g. for chickens at a younger age, with very low and very high gait scores).