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This study aimed to determine the effects of dietary ME and BW restriction on layer pullet sexual maturation, carcass composition and reproductive organs. Two trials were conducted: a precision feeding (PF) (Experiment 1) and a conventional (CON) experiment (Experiment 2). Experiment 1 was a 2 × 4 factorial arrangement with two feed allocation (FA) levels: meal every visit (MEV) or restricted to the lower limit of Lohmann Brown-Lite recommended BW; and three dietary ME levels: Low, Standard (Std), and High (2,600, 2,800, and 3,000 kcal/kg, respectively); the fourth treatment enabled birds to choose from the three diets (Choice). Experiment 2 was a 2 × 3 factorial arrangement with two FA levels: ad libitum or restricted to the lower limit of the strain recommended BW; and three dietary ME levels: Low, Std, and High. In Experiment 1, age at first egg (AFE), BW at first egg (BWFE), and carcass composition estimations were recorded. In Experiment 2, age at 50 % of egg production (A50), BW at 50 % of egg production (BW50), and chemical carcass composition were determined. Weight of reproductive organs were measured only in Experiment 2. Data were submitted to ANOVA on each experiment with the two main effects and age as fixed factors. Differences were reported where P ≤ 0.05. The BWFE and BW50 were greater in the MEV- and ad libitum-fed compared to the feed restricted birds in Experiments 1 and 2, respectively. Carcass lean and fat percentage were greater and lower in the feed restricted compared to the MEV- and ad libitum-fed pullets at 20 and 18 wk of age, respectively. Carcass fat percentage around photostimulation age (18 and 20 wk) was greater in the High ME compared to the Low ME fed pullets. Large yellow follicles (number and weight) and ovary (weight and percentage) were greater in ad libitum-fed compared to feed restricted birds. In conclusion, pullets fed greater dietary ME increased fat deposition and feed restricted birds had delayed sexual maturation., Competing Interests: Declaration of competing interest The authors declare that there are no conflicts of interest., (Copyright © 2024. Published by Elsevier Inc.)

The objective of this study was to develop appropriate correction equations for dual energy X-ray absorptiometry (DXA) for total carcass composition of live meat- and egg-type chickens. Linear (bivariate linear and multivariate linear) and nonlinear (polynomial, multivariate polynomial, broken-line and Gompertz) equations were used to estimate carcass composition of DXA-scanned birds based on chemical proximate analysis. A total of 288 laying females (10-30 wk of age) and 305 broiler breeder females (4-32 wk of age) were used. The same birds scanned by DXA were dissected and utilized for whole-body proximate chemical analysis for body lean, fat, and mineral content (ash). As indicators of carcass fat and lean, abdominal fat pad and breast muscle weights were also recorded. Models were evaluated using root mean square error (RMSE), Bayesian Information Criterion (BIC), coefficient of determination (R 2 ), Durbin Watson test for autocorrelation (DW), and residuals observation (RES). Model estimations were done separately by strain or combined. Estimations of composition responses fit at least 1 of each linear and nonlinear models for the egg- and meat-type chickens on all parameters estimated (P < 0.05). In the egg-type chickens, multivariate linear regression was the best fit for body lean with the lowest RMSE and BIC, and highest R 2 whereas body fat, body ash, and breast muscle were best predicted by the multivariate polynomial model. In the meat-type chickens, body lean was best predicted by the multivariate linear model with the lowest RMSE and BIC, and the highest R 2 whereas the multivariate polynomial was the most parsimonious model for body fat, body ash, and abdominal fat. Positive autocorrelations were observed in several models tested for body fat, body ash, breast muscle, and abdominal fat pad when both strains were analyzed combined (P < 0.05). In summary, a strain-based correction is recommended to all the parameters, with exception of the BW estimation. Correction equations developed in this study demonstrated that the DXA technique is a reliable alternative to proximate chemical analysis in egg- and meat-type chickens., Competing Interests: DISCLOSURES The authors declare that there are no conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

This study aimed to evaluate the effect of early growth (EG) and time of maximum pubertal growth peak (I2) on development, feed efficiency, carcass composition, and sexual maturation of broiler breeder females. Target BW trajectories were designed by changing coefficients of a 3-phase Gompertz model fit to the recommended BW target of Ross 308 breeders, [Formula: see text] . In each phase i, biologically relevant coefficients describe the amount of BW gain (g i ), the rate of growth (b i ), and the inflection point (I i ), which is the time when the growth rate for that phase is at its maximum rate. The study consisted of a 6 × 2 factorial arrangement, with six I2 levels (I from phase 2) and two EG levels. The I2 coefficients were 15, 17, 19, 21 (standard), 22, and 23 in wk. The EG treatments were: EG0, where g 1 and g 2 coefficients estimated from the standard from the breeder recommended BW were unchanged; and EG20, where 20% of the gain (g 2 ) in phase 2 (pubertal phase) was shifted to phase 1 (g 1 ; prepubertal phase). Two-hundred-eighty-eight Ross 308 pullets were randomly assigned to the twelve BW growth trajectories and fed using a precision feeding system from 0 to 28 wk of age. Body composition variables were submitted to three-way ANOVA, with EG, I2, and age as fixed sources of variation. Analysis of covariance was conducted on the remaining dependent variables with EG as fixed effect, I2 as a continuous fixed effect, and age as continuous random effect. Differences were reported at P ≤ 0.05. The BW of females followed their target BW, and ADFI differed depending on the amount of feed required to achieve their respective BW targets. Breast fleshing score was 0.2 greater in the EG20 compared to EG0. The number of juvenile primary wing feathers and age at first egg decreased by 0.4 and 0.9 d, respectively, per wk of earlier I2. Advancing I2 resulted in birds with increased carcass fat deposition from 16 to 28 wk of age. Carcass fat was 1.3- to 1.6-fold greater in the EG20 only from 4 to 16 wk of age. Early growth increased mostly pullet muscle and skeletal characteristics whereas advancing I2 advanced sexual maturity and increased carcass fat deposition around sexual maturation time., Competing Interests: Disclosures The authors declare that they have no competing financial interests or personal relationships that could have appeared to influence the work reported in the present study., (Copyright © 2024. Published by Elsevier Inc.)

Within poultry production systems, models have provided vital decision support, opportunity analysis, and performance optimization capabilities to nutritionists and producers for decades. In recent years, due to the advancement of digital and sensor technologies, 'Big Data' streams have emerged, optimally positioned to be analyzed by machine-learning (ML) modeling approaches, with strengths in forecasting and prediction. This review explores the evolution of empirical and mechanistic models in poultry production systems, and how these models may interact with new digital tools and technologies. This review will also examine the emergence of ML and Big Data in the poultry production sector, and the emergence of precision feeding and automation of poultry production systems. There are several promising directions for the field, including: (1) application of Big Data analytics (e.g., sensor-based technologies, precision feeding systems) and ML methodologies (e.g., unsupervised and supervised learning algorithms) to feed more precisely to production targets given a 'known' individual animal, and (2) combination and hybridization of data-driven and mechanistic modeling approaches to bridge decision support with improved forecasting capabilities., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

Broiler breeders are subjected to feed restriction programs to control excessive growth. However, current levels of feed restriction and concomitant growth restriction are becoming severe, raising welfare and suboptimal reproductive performance concerns in underfed breeders. To circumvent the issue, our previous studies investigated the effects of new strategic growth curves, with various degrees of relaxed growth restrictions, on broiler breeders and their progeny's performance. The broiler breeder study was conducted with 40 Ross 708 broiler breeder pullets reared on 1 of 10 target growth trajectories using a precision feeding (PF) system. The growth trajectories were designed with 2 levels of the amount of prepubertal BW gain and 5 levels of pubertal growth timing. The prepubertal BW gain (g 1 ) was estimated from the breeder-recommended standard BW gain (Standard g 1 ) target, or 10% higher (High g 1 ). The pubertal growth timing (I 2 ) was advanced such that it happened at I 2 -0% = 22.29 wk, I 2 -5% = 21.16 wk, I 2 -10% = 20.05 wk, I 2 -15% = 18.94 wk, I 2 -20% = 17.82 wk of age. Two broiler experiments with different maternal ages (35 and 42 wk) were conducted as the extension of the breeder experiment to evaluate the intergenerational effects of a reduced degree of maternal prepubertal phase growth restriction and earlier maternal pubertal phase growth on offspring growth and development. The current paper investigated the economic aspects of implementing the growth curves using the partial budget analysis. Increasing prepubertal BW gain by 10% and advancing the pubertal growth phase by 20% (scenario 10) could increase margin over feed and chick cost for the hatching egg producers by CDN$1.97/hen. For broiler chicken supply chain as a whole, the highest differential margin over feed and chick cost was for maternal growth scenario 10 from 42-wk-old hens. The latter margin over feed and chick cost was greater than that of breeder-recommended maternal growth (from 35-wk-old hens) by $0.1053/kg live chicken under the current economic situation., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

The management of body weight (BW) in broiler breeder pullets is critical to offset the negative correlation between their growth potential and reproductive success. Therefore, a precision feeding system was developed to allocate feed individually based on real-time BW in more frequent, smaller portions. However, this system requires access beyond the 8 h daylength of the rearing period. Since green and red spectra have been shown to stimulate growth and sexual maturation, respectively, this study aimed to evaluate the impact of continuous supplemental illumination of feeders with monochromatic wavelengths on sexual maturation. Furthermore, the best combination of supplemental and daytime lighting for optimizing the pullet-to-hen transition period was investigated. This study contained a 2 × 4 × 2 factorial arrangement, with 2 daytime lights (dtRED and dtGREEN; n = 2 rooms), 4 supplemental lights (sBLUE, sGREEN, sRED, and sCON; n = 12 pens), and 2 supplemental intensities (High and Low). At 3 wk of age (woa), 480 female Ross 708 chicks were randomly distributed across treatments (n = 10/pen). All birds were feed restricted per management guidelines and maintained under 8 h of dtRED or dtGREEN. Birds were photostimulated at 20 woa with 14L:10D. All birds were weighed weekly, with age at first egg (AFE) and production rate calculated weekly per pen. Birds under sRED were heavier than all other treatments from 27 woa to the end of the study (P < 0.001; 30 woa), resulting in hens that were over 400-g heavier. This resulted from a delayed AFE and lower production rate under sRED, with higher intensity further hindering reproductive performance (P < 0.001). Interestingly, despite the inhibitory effect of continuous red lighting (sRED) on reproduction, dtRED resulted in a 3.15% higher rate of lay than dtGREEN. Therefore, this study suggests that while red light remains superior at stimulating reproduction, continuous red supplemental lighting results in photorefractoriness. Thus, we recommend green light in PF systems., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Growth models are important for optimization of feed formulation and breeding programs in turkeys. The objectives of this study were 1) to compare sex and line differences in turkeys in parameter estimates of mono- and di-phasic Gompertz growth models, and 2) to evaluate mono and diphasic mixed Gompertz growth models to determine the variation in parameter estimates in a group of female line turkey toms. A total of 1,056 manually recorded weekly average body weight (BW) observations from male and female turkeys of a male and female line from weeks 1 to 20 were used for objective 1. Daily median values of automatically collected individual BW of female line turkey toms were used for objective 2 and random components associated with individual subject animals related to mature weight and/or timing of maximum gain during each phase were introduced in the Gompertz model. Growth curve shapes were different between male line toms, male line hens, female line toms, and female line hens (P < 0.001). However, inflection points were similar between male and female line toms and between male and female line hens (14.06 vs. 13.72 wk and 11.22 and 10.71 wk, respectively), while mature BW differed between lines by 6.49 and 3.81 kg for toms and hens, respectively. The normalized growth rate constant (growth rate constant corrected for mature weight) was around the same magnitude between male and female line toms (0.0031 vs. 0.0038, respectively), but slightly lower in male line hens compared to female line hens (0.0072 vs. 0.0091, respectively). Diphasic Gompertz models described growth better in all line × sex combinations compared to the monophasic models (P < 0.001) and mixed diphasic Gompertz models showed improved fit over mixed monophasic Gompertz models. The correlation structure of the random components identified that individuals with a higher mature weight had a later inflection point and lower growth rate coefficients. These results provide tools for improved breeding practices and a structure to evaluate the effects of dietary or environmental factors on growth trajectories., (© The Author(s) 2023. Published by Oxford University Press on behalf of the American Society of Animal Science. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

The Scholarship of Teaching and Learning, also referred to as SOTL, provides a framework for instructors to evaluate student learning and use evidence to determine pedagogical changes in the classroom. Engagement in SOTL challenges scholars to ask questions about their teaching practices and share with a larger community of practice. Examples of this include manuscript submissions to peer-reviewed journals, presenting abstracts at conferences, and other outlets that allow scholars to disseminate their findings. SOTL practices can be applied within an individual classroom or across a curriculum. Additionally, the promotion and tenure process at many institutions of higher education are highly recommending that faculty demonstrate impact on student learning. This symposium, presented at the 2022 Poultry Science Association Annual Meeting, highlighted best practices in SOTL, implementation of SOTL programming, and discussed using SOTL as a tool to evaluate teaching effectiveness. Poultry and animal science educators shared their experiences with implementing SOTL in their classroom and the benefits to students. From this symposium, we can conclude that there are multiple ways to document teaching excellence and conduct SOTL projects. This is of interest to educators implementing scholarly teaching in their classrooms., Competing Interests: Disclosures None., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

The effect of commercial selection by poultry breeders on the growth, efficiency, and sexual maturity of broiler breeders was studied using 2 University of Alberta Meat Control strains unselected since 1957 and 1978 (AMC-1957 and AMC-1978, respectively) and 2 strains originating from the University of Arkansas; 1995 Random-bred (1995RB) and 2015 Random-bred (2015RB). A study with a 4 × 2 factorial arrangement was conducted with the 4 strains fed at either ad libitum, or restricted levels to achieve a current commercial breeder target BW profile. Growth rate, feed intake, feed efficiency, age at sexual maturity, carcass components, and body conformation were measured. To assess reproductive development, birds were assigned to 2 fates: dissected at photostimulation or dissected after the second oviposition. At 22.4 wk of age, the restricted-fed AMC-1957, AMC-1978, 1995RB, and 2015RB reached 100, 61, 46, and 38% of their ad libitum-fed counterparts' BW, respectively. During the rearing phase, the amount of feed needed to maintain restricted-fed birds on the target BW was 99.4, 57, 29.5, and 24.9% of their ad libitum-fed counterparts for AMC-1957, AMC-1978, 1995RB, and 2015RB, respectively. Feed restricted birds in the 2015RB had lower heat production relative to the AMC-1957 and AMC-1978, which shows that modern strains utilized feed more efficiently compared to the antique strains. This might be related to the increasing severity of feed restriction of broiler breeders over the past 60 years. Relative to AMC-1957 and AMC-1978 strains, the 1995RB and 2015RB strains had heavier breast muscle and lower fat pad weight. Although the pubertal threshold for age and BW have increased over the last 6 decades, changes in selection programs for feed efficiency have resulted in broiler breeders that prioritize nutrient allocation to growth and breast development rather than adipose storage. As a result, feed restricted modern broiler breeders may have marginally sufficient fat resources to support reproduction., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

Blood concentration of corticosterone (CORT) is a measure of welfare in feed restricted broiler breeders. The RIA and ELISA have been routinely used for measuring CORT in blood, excreta, and feather. Due to the presence of some confounding factors in the aforementioned colorimetric enzyme reaction methods, some methodological difficulties have been attributed to those assays. The correlation between broiler breeder plasma CORT concentrations, measured using ELISA and a novel liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, was the focus of the current study. A total of 36 broiler breeder pullets were used, of which 30 were randomly assigned to one of 10 unique growth trajectories, and 6 were assigned to an unrestricted group. We designed the growth trajectories using a 3-phase Gompertz growth model with 10 levels of BW gain in the prepubertal and pubertal growth phases, ranging from the breeder-recommended target BW (CON) to 22.5% higher (CON+22.5%), in 2.5% increments. The BW trajectories were applied to each individual bird using a precision feeding (PF) system, which collected BW and feed intake data. The birds were classified based on age at first egg (AFE), and 12 birds each having the highest and lowest AFE was selected for the CORT study. Then median photostimulation BW of the candidate birds was used to define the upper (heavy BW) and lower (standard BW) extremes, and plasma CORT levels were evaluated by ELISA and LC-MS/MS methods from their blood collected at 18, 20, 22, 24, and 26 wk of age. Concentrations of plasma CORT measured using ELISA method were highly correlated (r = 0.95; P < 0.001) with values measured using LC-MS/MS method, validating interchangeably usage of both methods to measure plasma CORT in broiler breeders. Plasma CORT levels were not affected by photostimulation BW or breeders' age, indicating same welfare status between the precision fed high and low BW groups., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)