DERIVING ECONOMIC VALUES FOR REACTION NORMS OF GROWTH IN PIGS

SUMMARY Slopes of reaction norm models, also called reaction norms (RN), are alternative traits used in animal breeding for selection of genotypes that perform more consistently across a range of environments. Environmental sensitivity is of economic importance when the environment where selection takes place differs considerably from the commercial environment of slaughter pigs. The position on the environmental trajectory where intercept of reaction norm models is defined influences the economic values (EV) for slope and intercept. This position has to correspond to the trait definitions of intercept and slope of reaction norm models used to estimate variance components. The magnitude of EV for RN depends on the difference between the selection and production environments and the EV for the trait of interest. Economic values for RN may be negative or positive depending on whether the production environment is below or above the selection environment. Non-linear EV for growth across the environmental trajectory had minimal impact on the EV for RN of growth. Further genetic and economic analyses of extensive industry data are required to better quantify the economic importance of RN in pig breeding. INTRODUCTION Reaction norms quantify genotype by environment interactions by describing the response of genotypes to varying environmental conditions It was the aim of this paper to discuss economic implications of genetic differences in environmental sensitivity and to define EV for RN when selection is in the average environment using growth rate of pigs as an example trait

History and author analysis of the World Congresses on Genetics Applied to Livestock Production

It is almost fifty years since the first World Congress on Genetics Applied to Livestock Production (WCGALP) was convened in Spain in 1974. This paper, targeted for the early-career scientist session, details the history and evolution of WCGALP, and outlines gender composition of the Permanent International Committee, session chairs, plenary and invited speakers, and authors. Data containing 24,351 author records from all WCGALP proceedings, and old programs were used for the analyses. In the early years, there were few women involved in any aspect of WCGALP, however, more recent congresses have featured an increasing proportion of women on WCGALP committees and serving as session chairs. Based on recent data, gender is not playing a determining role in selection of submitted papers for oral presentations. We recommend greater gender diversity on WCGALP committees and encourage early-career scientists to actively participate in WCGALP conferences to further increase the diversity of future congresses

Economic weights for feed intake in the growing pig derived from a growth model and an economic model

Economic weights are obtained for feed intake using a growth model and an economic model. The underlying concept of the growth model is the linear plateau model. Parameters of this model are the marginal ratio (MR) of extra fat and extra protein deposition with increasing feed intake (FI) and the maximum protein deposition (Pdmax). The optimum feed intake (FI0) is defined as the minimum feed intake that meets energy requirements for Pdmax. The effect of varying FI and MR on performance traits was determined.An increase in FI results in a larger increase in growth rate with lower MR. For a given MR, feed conversion ratio is lowest when FI equals FI0. Lean meat percentage (LMP) is largest for a low MR in combination with a low FI. The decrease in LMP with higher FI is largest when FI exceeds FI0.Economic weights for FI, MR and Pdmax depend on FI in relation to FI0.Economic weights for FI are positive when FI is less than FI0 and negative when FI is larger than FI0. The MR has only then a negative economic weight, when FI is below FI0.Economic weights of FI and MR have a larger magnitude with lower MR and lower FI. In contrast, economic weights for growth rate and FI derived from the economic model only change in magnitude and not in sign with different levels of these traits. The economic model always puts a negative economic weight on FI since it expresses profit due to a decrease in FI with constant growth rate and LMP. This holds the risk of continuous decrease in FI in pig breeding programs. In contrast, the use of growth models for genetic improvement allows direct selection for an optimum feed intake which maximizes feed efficiency in combination with maximum lean meat growth. It is concluded that recording procedures have to be adapted to collect the data necessary to implement growth models in practical pig breeding applications

Life cycle assessment to predict individual environmental impacts: towards selection for sustainable pig production

A life cycle assessment approach is proposed to quantify four environmental impacts at the individual pig level. The approach was applied to two lines divergently selected for feed efficiency, including simulations of performances with two diets. Significant line differences were obtained with least-cost diets for environmental impacts and profit (P0.85), and moderate

“I Ran to Make a Point”: Predicting and Preventing Youth Runaway from Foster Care

Youth who run away from foster care experience danger to health and safety and increased risk of adverse child welfare outcomes. By applying a concurrent mixed-methods approach, this study aimed to develop a deeper understanding of runaway risk that used a person-centered lens and amplified youth voices. Collectively, this approach can inform service innovations to support youth placed in out-of-home care. Working with a foster care agency in Kansas, data sources comprised administrative data for youth ages 12 + in care, and interview data with 20 youth, 12 + in care. Quantitative analyses involved latent class analysis followed by multinomial logistic regression to investigate whether the population of youth in care was comprised of subpopulations with differential runaway risk and whether subpopulations would predict runaway behaviors. Qualitative analyses applied modified analytic inductive thematic analysis to explore critical life experiences that may act as risk or protective factors of running away from care. Results revealed four sub-populations which were characterized by their previous family and system experiences. Additionally, class membership, gender, number of siblings, and age were statistically significant predictors of runway behaviors. Youth interviews revealed five key themes on life experiences that mitigate or exacerbate youths’ runaway behaviors. Recommendations resulting from this study were provided in three key areas: (1) improving family visitation and maintaining youth connections with self-identified family and non-relative kin; (2) supporting service approaches for youth that honor and amplify their voices, choices, and family connections; and (3) improving placement quality and individualization of services

Evaluation of milk yield losses associated with Salmonella antibodies in bulk-tank milk in bovine dairy herds

The effect of Salmonella on milk production is not well established in cattle. The objective of this study was to investigate whether introduction of Salmonella into dairy cattle herds was associated with reduced milk yield and the duration of any effect. Longitudinal data from 2005 through 2009 were used, with data from 12 months before until 18 months after the estimated date of infection. Twenty-eight case herds were selected based on an increase in the level of Salmonella specific antibodies in bulk-tank milk from < 10 corrected optic density percentage (ODC%) to ≥ 70 ODC% between two consecutive 3-monthly measurements in the Danish Salmonella surveillance program. All selected case herds were conventional Danish Holstein herds. Control herds (n = 40) were selected randomly from Danish Holstein herds with Salmonella antibody levels consistently < 10 ODC%. A date of herd infection was randomly allocated to the control herds. Hierarchical mixed effect models with the outcome test day energy corrected milk yield (ECM)/cow were used to investigate the daily milk yield before and after the estimated herd infection date for cows in parity 1, 2 and 3+. Control herds were used to evaluate whether the effects in the case herds could be reproduced in herds without Salmonella infection. Herd size, days in milk, somatic cell count, season, and year were included in the models. The key results were that first parity cow yield was reduced by a mean of 1.4 kg (95% CI: 0.5 to 2.3) ECM/cow per day from seven to 15 months after the estimated herd infection date, compared with first parity cows in the same herds in the 12 months before the estimated herd infection date. Yield for parity 3+ was reduced by a mean of 3.0 kg (95% CI: 1.3 to 4.8) ECM/cow per day from seven to 15 months after herd infection compared with parity 3+ cows in the 12 months before the estimated herd infection. There were minor differences in yield in second parity cows before and after herd infection, and no difference between cows in control herds before and after the simulated infection date. There was a significant drop in milk yield in affected herds and the reduction was detectable several months after the increase in bulk-tank milk Salmonella antibodies. It took more than a year for milk yield to return to pre- infection levels

Feed intake and feeding behavior traits for gestating sows recorded using electronic sow feeders

Electronic sow feeding (ESF) systems are used to control feed delivery to individual sows that are group-housed. Feeding levels for gestating sows are typically restricted to prevent excessive body weight gain. Any alteration of intake from the allocated feeding curve or unusual feeding behavior could indicate potential health issues. The objective of this study was to use data recorded by ESF to establish and characterize novel feed intake and feeding behavior traits and to estimate their heritabilities. Raw data were available from two farms with in-house manufactured (Farm A) or commercial (Farm B) ESF. The traits derived included feed intake, time spent eating, and rate of feed consumption, averaged across or within specific time periods of gestation. Additional phenotypes included average daily number of feeding events (AFE), along with the cumulative numbers of days where sows spent longer than 30 min in the ESF (ABOVE30), missed their daily intake (MISSF), or consumed below 1 kg of feed (BELOW1). The appetite of sows was represented by averages of score (APPETITE), a binary value for allocation eaten or not (DA_bin), or the standard deviation of the difference between feed intake and allocation (SDA-I). Gilts took longer to eat than sows (15.5 ± 0.13 vs. 14.1 ± 0.11 min/d) despite a lower feed allocation (2.13 ± 0.00 vs. 2.36 ± 0.01 kg/d). The lowest heritability estimates (below 0.10) occurred for feed intake traits, due to the restriction in feed allocation, although heritabilities were slightly higher for Farm B, with restriction in the eating time. The low heritability for AFE (0.05 ± 0.02) may have reflected the lack of recording of nonfeeding visits, but repeatability was moderate (0.26 ± 0.03, Farm A). Time-related traits were moderately to highly heritable and repeatable, demonstrating genetic variation between individuals in their feeding behaviors. Heritabilities for BELOW1 (Farm A: 0.16 ± 0.04 and Farm B: 0.15 ± 0.09) and SDA-I (Farm A: 0.17 ± 0.04 and Farm B: 0.10 ± 0.08) were similar across farms. In contrast, MISSF was moderately heritable in Farm A (0.19 ± 0.04) but lowly heritable in Farm B (0.05 ± 0.07). Heritabilities for DA_bin were dissimilar between farms (Farm A: 0.02 ± 0.02 and Farm B: 0.23 ± 0.10) despite similar incidence. Individual phenotypes constructed from ESF data could be useful for genetic evaluation purposes, but equivalent capabilities to generate phenotypes were not available for both ESF systems

Improving sow welfare and outcomes in the farrowing house by identifying early indicators from pre-farrowing assessment

Poor outcomes reflect low performance during the farrowing and lactation periods and unanticipated sow removals. Since the period around farrowing has the highest risk for sow health issues, monitoring of sows in that time-period will improve both welfare and productivity. The aim of this study was to identify the most relevant risk factors for predicting poor outcomes and the implication for sow welfare. Identifying these factors could potentially enable management interventions to decrease incidences of compromised welfare or poor performance. Data from 1,103 sows sourced from two nucleus herds were recorded for a range of variables investigated as potential predictors of poor outcomes in the farrowing house. Poor outcomes (scored as binary traits) reflected three categories in a sow's lifecycle: farrowing, lactation, and removals. Univariate logistic regression was used to identify predictors in the first instance. Predictors from univariate analyses were subsequently considered together in multi-variate models. The least square means representing predicted probabilities of poor outcomes were then reported on the observed scale. Several predictors were significant across two different environments (farms) and for all three categories. These predictors included feed refusal (lack of appetite), crate fit, locomotion score, and respiration rate. Normal appetite compared to feed refusals reduced the risk of farrowing failure (13.5 vs. 22.2%, P = 0.025) and removals (10.4 vs. 20.4%, P P P = 0.025) and reduced piglet mortality (P P P = 0.014). Sows with higher respiration rates had a significantly (