@article{vier_dritz_orlando_diaz_camp_cast_lu_canavate_hamilton_knauer_et al._2024, title={Relationship between sow caliper measurements with sow reproductive performance and longevity in the herd}, volume={102}, ISSN={["1525-3163"]}, DOI={10.1093/jas/skae102.198}, abstractNote={Abstract Ideal conditioned sows are desired because they maximize herd performance, improve female well-being, and optimize financial outcomes. Sow productivity has increased, and body composition of females has changed, with sows being leaner and having less adipose tissue compared with their predecessors. Our objective was to determine the relationship between sow caliper measurements with sow reproductive performance and longevity in the herd. Data collected in four different production systems located in the US and Brazil were used, with 3,083, 356, 7,456, and 26,773 individual PIC Camborough observations represented within each of these databases. Caliper measurements were collected at due to farrow and weaned sows and were recorded in units, standardized to an ideal range of 12 to 15 units. Caliper change in lactation was determined as the caliper units at weaning minus the caliper units pre-farrowing. Response variables included proportion of born alive and stillborn piglets, lactation feed intake, as well as removal and mortality risk for all causes, or specifically for reproductive and pelvic organ prolapse (POP) causes. Data were analyzed using generalized linear mixed models, hazard ratio analysis, and survival models with the lmer, glmer, and surv functions of R. Sow served as the experimental unit. Caliper measurements at farrowing had curvilinear associations (P < 0.05) with percentage born alive piglets and percentage stillborn piglets. Increasing caliper units at farrowing resulted in linear reduction (P < 0.05) in lactation average daily feed intake and in linear increase (P < 0.05) in caliper losses during lactation. Sows losing 1 to 2, 3 to 4, or 5 and greater caliper units in lactation had 1.5, 1.8, and 2.4 times, respectively, greater risk (P < 0.05) of being removed from the herd in the next cycle compared with sows that gained 0 or more units. Reduced caliper units in due-to-farrow sows resulted in reduced probability (P < 0.05) of survival in the next cycle considering prolapse removal reasons. Sows with due to farrow caliper units of 12 to 15 had 1 to 1.6 times (95% Odd Ratio Confidence Interval), 9 to 11 had 1.2 to 2.1 times, and less than 9 caliper units 3.1 to 3.2 times greater risk of death or being removed from the herd due to POP compared with those with >15 units. Reduced caliper units in due-to-farrow sows resulted in reduced probability of survival in the next cycle considering all removal and mortality causes. Specifically, sows with less than 9 caliper units at farrowing had 2.0 times greater risk (P < 0.05) of removal and 4.4 times greater risk (P < 0.05) of mortality compared with sows with over 15 caliper units. In summary, both under and over-conditioned sows have reduced productivity. Underconditioned sows are at greater risk for mortality and for POP related removal.}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Vier, Carine M. and Dritz, Steve and Orlando, Weasley A. and Diaz, Julia A. Calderon and Camp, Jordi and Cast, Wayne R. and Lu, Ning and Canavate, Sergio and Hamilton, Dan and Knauer, Mark and et al.}, year={2024}, month={May}, pages={179–180} }
 @article{lin_flowers_jiang_knauer_lin_2024, title={The effect of temperature-humidity index in different pregnancy stages on litter traits in Taiwan Landrace sows}, volume={102}, ISSN={["1525-3163"]}, DOI={10.1093/jas/skae102.025}, abstractNote={Abstract Because of climate change, annual average temperatures are gradually rising. Hence, increasing heat stress can impair the litter traits of Taiwanese sows located in tropical and subtropical zones. However, some pregnancy stages may be impacted more by heat stress than other periods. Thus, the purpose of this study was to demonstrate the effect of temperature-humidity index (THI) in different pregnancy stages on total number born (TNB), number born alive (NBA), and stillborn rate (STB). Data were collected in two Taiwanese farms from 2008 to 2021 for TNB, NBA, and STB, while weather data were collected from the closest respective weather station. There were 4,247 and 6,812 pure line Landrace record from farm 1 and farm 2, respectively. Pregnancy stages included 28 d before mating (BEFORE), mating to 30 d of pregnancy (EARLY), 31 to 70 d of pregnancy (MIDDLE), and 71 d of pregnancy to farrowing (LATE). Average THI was calculated in each pregnancy stage and regression coefficients were estimated by linear mixed models within ASReml. A two-trait analysis was used to estimate regression coefficients and genetic correlations among TNB, NBA, and STB. Results showed THI impacted (P < 0.05) TNB and NBA BEFORE and EARLY, while THI influenced (P < 0.05) STB EARLY and MIDDLE. Regression coefficients for TNB were -0.0069 and -0.0228 for BEFORE and EARLY, respectively. For NBA, regression coefficients were 0.0106 and -0.0391 for BEFORE and EARLY, respectively. Regression coefficients for STB were -0.0651 and 0.1332 for EARLY and MIDDLE, respectively. Heritability estimates for TNB, NBA, and STB were 0.168, 0.113, and 0.069, respectively. Genetic correlations between TNB with NBA and STB were 0.913 and 0.539, respectively. While the genetic correlation between NBA and STB was 0.158. In conclusion, THI impacted BEFORE and EARLY stages for TNB and NBA, while the stages of EARLY and MIDDLE were impacted by THI for STB. Hence, control of the environments in these specific stages for sows could improve the performance of litter traits.}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Lin, Kai-Hsiang and Flowers, Billy and Jiang, Jicai and Knauer, Mark and Lin, En-Chung}, year={2024}, month={May}, pages={20–20} }
 @article{kittle_leonard_knauer_almond_2024, title={Water quality analysis and flow rate comparison between wean-finish swine barns}, volume={102}, ISSN={["1525-3163"]}, DOI={10.1093/jas/skae102.033}, abstractNote={Abstract Water is an essential nutrient to sustain life and a vital component of biological functioning, impacting regulation of pig body temperature along with transporting nutrients to the body. Drinker availability, position, design, water flow rate and pressure, and water quality are major components of pig water intake. The ideal water flow rate for wean-to-finish pigs is 1 L m-1. Excessive flow rates could limit pig water intake and increase humidity in the barn, while too little water flow can lead to a decrease in water intake and biological functioning of the pig. Water should not contain harmful substances and should be readily accessible to pigs. Compounds in water are highly variable depending on region, water source, and pH. Quality of water influences feed consumption along with pig health. Water can contain a variety of microorganisms such as bacteria, viruses, algae, and protozoa; while not all microorganisms are harmful a highly contaminated water analysis is an index of poor water quality. In this study water quality and water flow rates were analyzed across five wean-finish sites comprising 16 barns for three turns of finishing pigs. Water flow rates were measured twice per turn, wk 1 and wk 17. Each barn contained 36 pens and flow rate measurements were collected in 8 pens evenly distributed within the barn. One suspended water source was available per pen, with two nipple drinkers per water source. Water flow rates were averaged over each turn within barns. Average water flow rates were 1.42 L m-1 with standard deviation of 0.44 L m-1. Overall barn water flow rates ranged from 0.78 to 2.19 L m-1. Barn flow rates were compared over time to evaluate performance and maintenance of facilities. Water quality samples were also collected and submitted for standard water analysis. Results will provide information on management strategies to assess water quality and water flow rates in wean-finish facilities.}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Kittle, Olivia C. S. and Leonard, Suzanne M. and Knauer, Mark and Almond, Glen}, year={2024}, month={May}, pages={27–27} }
 @article{kittle_leonard_knauer_almond_2023, title={Comparison of Ammonia Concentrations Between Flush and Pull-Plug Waste Management Systems in Wean-Finish Swine Barns.}, volume={101}, ISSN={["1525-3163"]}, DOI={10.1093/jas/skad068.139}, abstractNote={Abstract}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Kittle, J. and Leonard, Suzanne M. and Knauer, Mark and Almond, Glen}, year={2023}, month={May} }
 @article{knauer_2023, title={Dead Sows do not Rear Piglets}, volume={101}, ISSN={["1525-3163"]}, DOI={10.1093/jas/skad341.214}, abstractNote={Abstract}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Knauer, Mark}, year={2023}, month={Oct}, pages={193–194} }
 @article{peppmeier_leonard_knauer_2023, title={Effect of Temperature and Humidity on Daily Feeding Behavior in Swine}, volume={101}, ISSN={["1525-3163"]}, DOI={10.1093/jas/skad068.010}, abstractNote={Abstract}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Peppmeier, Zack and Leonard, Suzanne M. and Knauer, Mark}, year={2023}, month={May} }
 @article{peppmeier_howard_knauer_leonard_2023, title={Estimating backfat depth, loin depth, and intramuscular fat percentage from ultrasound images in swine}, volume={17}, ISSN={["1751-732X"]}, url={https://doi.org/10.1016/j.animal.2023.100969}, DOI={10.1016/j.animal.2023.100969}, abstractNote={Fast, accurate, and reliable estimates of backfat depth, loin depth, and intramuscular fat percentage in swine breeding stock are used to increase genetic improvement and farm profitability. The objective of this study was to develop an equation-based model for the estimation of swine backfat depth, loin depth, and intramuscular fat percentage estimates obtained from longitudinal ultrasound images. Images were collected from purebred Duroc (n = 230), purebred Large White (n = 154), and commercial (n = 190) pigs born in January 2021 at three farms located in North Carolina. An Exapad ultrasound machine captured longitudinal images across the 10th to 13th ribs at 182 (±12.8 SD) days of pig age. The total number of images processed for Duroc, Large White, and commercial pigs was 1 385, 928, and 1 168 images, respectively. To establish a standard measurement for model comparison, trained personnel following standard company procedures using the BioSoft Toolbox (v4.0.1.2; Biotronics Inc., Ames, IA) obtained backfat and loin depth measurements from the images. Longissimus muscle intramuscular fat percentage was predicted using near-infrared spectroscopy at approximately 22 h postmortem. Backfat and loin depth estimation were conducted only for commercial pigs (n = 190) while intramuscular fat estimation was conducted on all pigs (n = 574). Average backfat depth, loin depth, and intramuscular fat percentage were 14.6 (±2.6 SD) mm, 63.7 (±5.5 SD) mm, and 2.21 (±0.82 SD) %. Image analysis and estimation model development were conducted in MATLAB R2021a. Edge detection via the image gradient was applied to segment ultrasound images into backfat, loin, and rib regions. Segmented images were used to estimate backfat depth, loin depth, and loin intramuscular fat percentage. After image quality control and filtering, the image inclusion rate for each breed-trait combination ranged from 76 to 97%. All Duroc and commercial pigs and 97% of Large White pigs were represented by at least one image for trait estimation. Coefficient of determination of models for the estimation of backfat depth, loin depth, and intramuscular fat percentage were 0.58, 0.57, and 0.56, respectively. Root mean square error of backfat depth, loin depth, and intramuscular fat estimation were 1.65 mm, 3.58 mm, and 0.54%, respectively. Results demonstrate the feasibility of using ultrasound image gradient and an equation-based approach to estimate swine backfat and loin depth, and intramuscular fat percentage. This equation-based approach to estimate carcass traits in live swine can enhance genetic improvement.}, number={10}, journal={ANIMAL}, author={Peppmeier, Z. C. and Howard, J. T. and Knauer, M. T. and Leonard, S. M.}, year={2023}, month={Oct} }
 @article{earnhardt-san_gray_knauer_2023, title={Genetic Parameter Estimates for Teat and Mammary Traits in Commercial Sows}, volume={13}, ISSN={["2076-2615"]}, DOI={10.3390/ani13152400}, abstractNote={The objective was to evaluate the genetics of sow teat and mammary traits at farrowing and at weaning. Data were recorded on 3099 Landrace × Large White F1 sows. Underline traits included the total teat number (TT), the functional teat number (FT), the non-functional teat number (NFT), the damaged teat number (DT), and the number of functional mammary glands (FMG). Variance components were estimated using AIREMLF90. Means for TT, FT, and NFT at farrowing were 14.93, 13.90, and 1.03, respectively. Heritability estimates for TT, FT, and NFT ranged from 0.18 to 0.37, 0.16 to 0.28, and 0.14 to 0.18, respectively. Estimates of heritability for DT and FMG at weaning were 0.03 and 0.06, respectively. Estimated genetic correlations between FT with TT and NFT were 0.68 to 0.78 and −0.19 to −0.57, respectively. Genetic correlation estimates between TT, FT, and NFT with the number weaned were 0.25, 0.50, and −0.38, respectively. An increase of one TT and FT enhanced (p < 0.05) the number weaned by 0.14 to 0.16 and 0.18 to 0.27 piglets, respectively. The results suggest that genetically increasing the number of functional teats on a sow at farrowing would improve the number of piglets at weaning.}, number={15}, journal={ANIMALS}, author={Earnhardt-San, Audrey L. and Gray, Kent A. and Knauer, Mark T.}, year={2023}, month={Aug} }
 @article{knauer_peppmeier_purvis_2023, title={Impact of Prefarrow Fat Supplementation on Piglet Survival and Subsequent Reproduction}, volume={101}, ISSN={["1525-3163"]}, DOI={10.1093/jas/skad341.344}, abstractNote={Abstract}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Knauer, Mark and Peppmeier, Zack and Purvis, Jerry}, year={2023}, month={Oct}, pages={302–303} }
 @article{knauer_2023, title={Impact of Vitamins C and E on Sow Mortality and Stillborn Rate}, volume={101}, ISSN={["1525-3163"]}, DOI={10.1093/jas/skad341.400}, abstractNote={Abstract}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Knauer, Mark}, year={2023}, month={Oct}, pages={352–353} }
 @article{knauer_peppmeier_leonard_2023, title={Sow Location Within Farrowing Room Impacts Reproduction During Heat Stress.}, volume={101}, ISSN={["1525-3163"]}, DOI={10.1093/jas/skad068.013}, abstractNote={Abstract}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Knauer, Mark and Peppmeier, Zack and Leonard, Suzanne M.}, year={2023}, month={May} }
 @article{knauer_bergstrom_hough_2023, title={Sow Supplementation with Vitamin C Enhances Pig Throughput}, volume={101}, ISSN={["1525-3163"]}, DOI={10.1093/jas/skad341.076}, abstractNote={Abstract}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Knauer, Mark and Bergstrom, Jon R. and Hough, Sara D.}, year={2023}, month={Oct}, pages={68–69} }
 @article{obermier_howard_gray_knauer_2023, title={The impact of functional teat number on reproductive throughput in swine}, volume={7}, ISSN={["2573-2102"]}, DOI={10.1093/tas/txad100}, abstractNote={Abstract}, number={1}, journal={TRANSLATIONAL ANIMAL SCIENCE}, author={Obermier, Dalton R. and Howard, Jeremy Thomas and Gray, Kent A. and Knauer, Mark T.}, year={2023}, month={Jan} }
 @article{nguyen_holt_knauer_abner_lobaton_young_2023, title={Towards rapid weight assessment of finishing pigs using a handheld, mobile RGB-D camera}, volume={226}, ISSN={["1537-5129"]}, url={https://doi.org/10.1016/j.biosystemseng.2023.01.005}, DOI={10.1016/j.biosystemseng.2023.01.005}, abstractNote={Pig weight measurement is essential for monitoring performance, welfare, and production value. Weight measurement using a scale provides the most accurate results; however, it is time consuming and may increase animal stress. Subjective visual evaluations, even when conducted by an experienced caretaker, lack consistency and accuracy. Optical sensing systems provide alternative methods for estimating pig weight, but studies examining these systems only focus on images taken from stationary cameras. This study fills a gap in existing technology through examining a handheld, portable RGB-D imaging system for estimating pig weight. An Intel RealSense camera collected RGB-D data from finishing pigs at various market weights. 3D point clouds were computed for each pig, and latent features from a 3D generative model were used to predict pig weights using three regression models (SVR, MLP and AdaBoost). These models were compared to two baseline models: median prediction and linear regression using body dimension measurements as predictor variables. Using 10-fold cross validation mean absolute error (MAE) and root-mean-square error (RMSE), all three latent feature models performed better than the median prediction model (MAE = 12.3 kg, RMSE = 16.0 kg) but did not outperform linear regression between weight and girth measurements (MAE = 4.06 kg, RMSE = 4.94 kg). Of the models under consideration, SVR performed best (MAE = 9.25 kg, RMSE = 12.3 kg, mean absolute percentage error = 7.54%) when tested on unseen data. This research is an important step towards developing rapid pig body weight estimation methods from a handheld, portable imaging system by leveraging deep learning feature outputs and depth imaging technology.}, journal={BIOSYSTEMS ENGINEERING}, author={Nguyen, Anh H. and Holt, Jonathan P. and Knauer, Mark T. and Abner, Victoria A. and Lobaton, Edgar J. and Young, Sierra N.}, year={2023}, month={Feb}, pages={155–168} }
 @article{wiegert_knauer_shah_2022, title={EVAPORATIVE PAD COOLING IMPACTS ON BARN ENVIRONMENT AND FINISHING PIG PERFORMANCE}, volume={38}, ISSN={["1943-7838"]}, DOI={10.13031/aea.14810}, abstractNote={Highlights}, number={2}, journal={APPLIED ENGINEERING IN AGRICULTURE}, author={Wiegert, Jeffery and Knauer, Mark and Shah, Sanjay B.}, year={2022}, pages={351–359} }
 @article{yu_shah_knauer_boyette_stikeleather_2021, title={Comprehensive Evaluation of a Landscape Fabric Based Solar Air Heater in a Pig Nursery}, volume={14}, ISSN={["1996-1073"]}, url={https://doi.org/10.3390/en14217258}, DOI={10.3390/en14217258}, abstractNote={Supplementing fossil fuels with solar air tempering for brooding young livestock could reduce energy use and improve indoor air quality. Metal transpired solar collectors (TSC) are effective but too expensive for heating livestock buildings. An inexpensive 12.7 m2 dark grey landscape-fabric-based transpired solar collector (fTSC) was evaluated in a swine nursery with two herds of pigs. A fraction of the fTSC area was underlain with phase change material (PCM) to store excess heat. The Test room with the fTSC was compared with an adjacent identical Control room, each with 120 piglets. The fTSC provided supplemental heating, e.g., with a suction velocity (Vs) of 0.027 m/s during a 9 h period, air temperature was increased by 11.6 °C (mean irradiance of 592 W/m2). Between 4 pm and 9 pm that same day, the PCM increased air temperature by 3.9 °C. The fTSC did not reduce propane use or improve pig performance. Higher Vs, operational changes and controller modifications could improve system performance and reduce cost. Modeling could be used to optimize PCM use. Hence, this very low-cost fabric-based solar air heater offers potential for considerable reduction in heat energy use in livestock barns.}, number={21}, journal={ENERGIES}, author={Yu, Li and Shah, Sanjay B. and Knauer, Mark T. and Boyette, Michael D. and Stikeleather, Larry F.}, year={2021}, month={Nov} }
 @article{knauer_peppmeier_2021, title={Effect of Substandard Teats on Piglet and Sow Performance}, volume={99}, ISSN={["1525-3163"]}, DOI={10.1093/jas/skab054.225}, abstractNote={Abstract}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Knauer, Mark and Peppmeier, Zack}, year={2021}, month={May}, pages={133–133} }
 @article{knauer_mani_marsteller_iseri_kremer_2021, title={Evaluating the Performance of Grow-finish Pigs Supplemented with Butipearl (R) Z and Kemtrace (R) Chromium During Natural Heat Stress Exposure}, volume={99}, ISSN={["1525-3163"]}, DOI={10.1093/jas/skab054.294}, abstractNote={Abstract}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Knauer, Mark and Mani, Venkatesh and Marsteller, Tom and Iseri, Vanessa and Kremer, Brian}, year={2021}, month={May}, pages={174–174} }
 @article{harlow_renwick_shuping_sommer_lents_knauer_nestor_2021, title={Evidence that pubertal status impacts kisspeptin/neurokinin B/dynorphin neurons in the gilt(dagger)}, volume={105}, ISSN={["1529-7268"]}, DOI={10.1093/biolre/ioab189}, abstractNote={Abstract}, number={6}, journal={BIOLOGY OF REPRODUCTION}, author={Harlow, KaLynn and Renwick, Allison N. and Shuping, Sydney L. and Sommer, Jeffrey R. and Lents, Clay A. and Knauer, Mark T. and Nestor, Casey C.}, year={2021}, month={Dec}, pages={1533–1544} }
 @article{harlow_renwick_shuping_sommer_knauer_nestor_2020, title={Effects of genetic selection for early puberty on the hypothalamic-pituitary-ovarian axis in gilts}, volume={98}, ISSN={["1525-3163"]}, DOI={10.1093/jas/skaa054.368}, abstractNote={Abstract}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Harlow, KaLynn and Renwick, Allison and Shuping, Sydney and Sommer, Jeff and Knauer, Mark and Nestor, Casey}, year={2020}, month={Nov}, pages={212–212} }
 @article{knauer_purvis_lu_orlando_vier_cast_2020, title={Evaluation of the NRC (2012) model in estimating standard maintenance metabolizable energy requirement of PIC sows during midgestation}, volume={98}, ISSN={["1525-3163"]}, DOI={10.1093/jas/skaa054.170}, abstractNote={Abstract}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Knauer, Mark and Purvis, Jerry and Lu, Ning and Orlando, Uislei and Vier, Carine and Cast, Wayne}, year={2020}, month={Nov}, pages={98–98} }
 @article{see_knauer_2019, title={Associations with four generations of divergent selection for age at puberty in swine}, volume={97}, ISSN={["1525-3163"]}, DOI={10.1093/jas/skz129}, abstractNote={The objective was to evaluate 4 generations of divergent selection for age at puberty (young age at puberty = YOUNG; old age at puberty = OLD) in swine. Composite Landrace × Large White animals (n = 4,941) were reared at the North Carolina Department of Agriculture Tidewater Research Station. At 130 d of age, gilts were exposed to mature boars for 7 min daily. Estrous detection continued for 90 d. Puberty was defined as first observed standing reflex in the presence of a boar. Reproductive and performance traits included: age at puberty (AGEPUB), probability of a gilt reaching puberty by 220 d of age (PUB), puberty weight (PUBWT), pubertal estrus (LEN1), length of second estrus (LEN2), vulva width at puberty (VW1), vulva width at second estrus (VW2), gilt birth weight (BWT), gilt weaning weight (WWT), loin eye area (LEA), backfat depth (BF), and weight (WT178) were measured at 178 d of age on average. Variance components were estimated utilizing an animal model in ASReml 4.1. Models included fixed effects of generation and sex, a random common litter effect, and a random animal genetic effect. Covariates were fit for reproductive traits (age at boar exposure), LEA and BF (WT178) and WT178 (age weighed). In generation 4, YOUNG and OLD gilts had on average a PUB of 87% and 64%, respectively, and AGEPUB of 163 and 183 d, respectively. Heritability estimates for AGEPUB, PUB, PUBWT, LEN1, LEN2, VW1, VW2, BWT, WWT, LEA, BF, and WT178 were 0.40, 0.07, 0.39, 0.19, 0.17, 0.36, 0.48, 0.20, 0.12, 0.42, 0.43, and 0.37, respectively. Common litter effect estimates for AGEPUB, PUB, PUBWT, LEN1, LEN2, VW1, VW2, BWT, WWT, LEA, BF, and WT178 were 0.08, 0.14, 0.03, 0.00, 0.01, 0.05, 0.00, 0.03, 0.29, 0.02, 0.10, and 0.11, respectively. Genetic correlations between AGEPUB with PUBWT, LEN1, LEN2, VW1, VW2, BWT, WWT, LEA, BF, and WT178 were 0.83, -0.22, -0.31, 0.25, 0.19, -0.08, -0.29, 0.15, -0.21, and -0.43, respectively. Results suggest selection for reduced AGEPUB in swine would decrease AGEPUB and increase PUB.}, number={6}, journal={JOURNAL OF ANIMAL SCIENCE}, author={See, Garrett M. and Knauer, Mark T.}, year={2019}, month={Jun}, pages={2320–2328} }
 @article{quick_knauer_2019, title={Effect of gilt feeding level and length of increased feeding level in late gestation on piglet birth weight.}, volume={97}, ISSN={["1525-3163"]}, DOI={10.1093/jas/skz122.410}, abstractNote={Abstract}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Quick, James K. and Knauer, Mark}, year={2019}, month={Jul}, pages={233–233} }
 @article{wiegert_knauer_2019, title={Meta-analysis of increasing lysine and energy in late gestation on piglet growth, colostrum composition and piglet throughput.}, volume={97}, ISSN={["1525-3163"]}, DOI={10.1093/jas/skz122.367}, abstractNote={Abstract}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Wiegert, Jeffrey and Knauer, Mark}, year={2019}, month={Jul}, pages={208–208} }
 @article{peppmeier_obermier_knauer_2019, title={Production trait differences between show pig and commerical genetic lines.}, volume={97}, ISSN={["1525-3163"]}, DOI={10.1093/jas/skz122.297}, abstractNote={Abstract}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Peppmeier, Zack and Obermier, Dalton R. and Knauer, Mark}, year={2019}, month={Jul}, pages={168–168} }
 @article{obermier_peppmeier_knauer_2019, title={Structural conformation differences between show pigs and commercial genetic lines.}, volume={97}, ISSN={["1525-3163"]}, DOI={10.1093/jas/skz122.070}, abstractNote={Abstract}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Obermier, Dalton R. and Peppmeier, Zack and Knauer, Mark}, year={2019}, month={Jul}, pages={39–39} }
 @article{obermier_knauer_graham_frobose_2019, title={The effects of lift crates on sow performance and litter survival.}, volume={97}, ISSN={["1525-3163"]}, DOI={10.1093/jas/skz122.411}, abstractNote={Abstract}, journal={JOURNAL OF ANIMAL SCIENCE}, author={Obermier, Dalton R. and Knauer, Mark and Graham, Amanda and Frobose, Hyatt}, year={2019}, month={Jul}, pages={233–233} }
 @article{putz_tiezzi_maltecca_gray_knauer_2018, title={A comparison of accuracy validation methods for genomic and pedigree-based predictions of swine litter size traits using Large White and simulated data}, volume={135}, ISSN={["1439-0388"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85040771964&partnerID=MN8TOARS}, DOI={10.1111/jbg.12302}, abstractNote={Summary}, number={1}, journal={JOURNAL OF ANIMAL BREEDING AND GENETICS}, author={Putz, A. M. and Tiezzi, F. and Maltecca, C. and Gray, K. A. and Knauer, M. T.}, year={2018}, month={Feb}, pages={5–13} }
 @article{lu_jiao_tiezzi_knauer_huang_gray_maltecca_2017, title={The relationship between different measures of feed efficiency and feeding behavior traits in Duroc pigs}, volume={95}, DOI={10.2527/jas2017.1509}, number={8}, journal={Journal of Animal Science}, author={Lu, D. and Jiao, S. and Tiezzi, F. and Knauer, M. and Huang, Y. and Gray, K. A. and maltecca}, year={2017}, pages={3370–3380} }
 @article{knauer_baitinger_2015, title={The sow body condition caliper}, volume={31}, DOI={10.13031/aea.31.10632}, abstractNote={Abstract. Sows throughout the world are commonly fed to a subjective body condition target. Therefore, the objective of the study was to develop a fast and accurate, objective tool to measure sow body condition. A prototype caliper was developed to quantify the angularity from the spinous process to the transverse process of a sow’s back. The sow caliper technology is based on the premise that as a sow loses weight, fat and muscle her back becomes more angular. The arms of the caliper were 3.8 cm tall and could be adjusted to 16.5, 21.6, 26.7, or 31.8 cm wide. Landrace A— Large White gilts and multiparous sows (n = 315) were utilized to associate the caliper with weight, backfat, muscling, and visual body condition at commercial sow farms in eastern North Carolina. The caliper was evaluated at locations on the sow’s back: behind the shoulder, middle of the back, and at the last rib. Sow weight was estimated and parity recorded. Backfat (BF) and loin depth (LD) were measured using an Aloka 500V SSD ultrasound machine. Visual body condition (BCS) was scored using a scale of 1 (thin) to 5 (over conditioned). Weight, BF, LD, and BCS explained 51% to 71% of the variation in caliper measures. Results suggest the optimal sow caliper width was 26.7 cm and measurements should be taken at the last rib. The sow body condition caliper is an objective tool that can be used by farmers to standardize sow body condition.}, number={2}, journal={Applied Engineering in Agriculture}, author={Knauer, M. T. and Baitinger, D. J.}, year={2015}, pages={175–178} }
 @article{putz_tiezzi_maltecca_gray_knauer_2015, title={Variance component estimates for alternative litter size traits in swine}, volume={93}, ISSN={["1525-3163"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84975508749&partnerID=MN8TOARS}, DOI={10.2527/jas.2015-9416}, abstractNote={Litter size at d 5 (LS5) has been shown to be an effective trait to increase total number born (TNB) while simultaneously decreasing preweaning mortality. The objective of this study was to determine the optimal litter size day for selection (i.e., other than d 5). Traits included TNB, number born alive (NBA), litter size at d 2, 5, 10, 30 (LS2, LS5, LS10, LS30, respectively), litter size at weaning (LSW), number weaned (NW), piglet mortality at d 30 (MortD30), and average piglet birth weight (BirthWt). Litter size traits were assigned to biological litters and treated as a trait of the sow. In contrast, NW was the number of piglets weaned by the nurse dam. Bivariate animal models included farm, year-season, and parity as fixed effects. Number born alive was fit as a covariate for BirthWt. Random effects included additive genetics and the permanent environment of the sow. Variance components were plotted for TNB, NBA, and LS2 to LS30 using univariate animal models to determine how variances changed over time. Additive genetic variance was minimized at d 7 in Large White and at d 14 in Landrace pigs. Total phenotypic variance for litter size traits decreased over the first 10 d and then stabilized. Heritability estimates increased between TNB and LS30. Genetic correlations between TNB, NBA, and LS2 to LS29 with LS30 plateaued within the first 10 d. A genetic correlation with LS30 of 0.95 was reached at d 4 for Large White and at d 8 for Landrace pigs. Heritability estimates ranged from 0.07 to 0.13 for litter size traits and MortD30. Birth weight had an h of 0.24 and 0.26 for Large White and Landrace pigs, respectively. Genetic correlations among LS30, LSW, and NW ranged from 0.97 to 1.00. In the Large White breed, genetic correlations between MortD30 with TNB and LS30 were 0.23 and -0.64, respectively. These correlations were 0.10 and -0.61 in the Landrace breed. A high genetic correlation of 0.98 and 0.97 was observed between LS10 and NW for Large White and Landrace breeds, respectively. This would indicate that NW could possibly be used as an effective maternal trait, given a low level of cross-fostering, to avoid back calculating litter size traits from piglet records. Litter size at d 10 would be a compromise between gain in litter size at weaning and minimizing the potentially negative effects of the nurse dam and direct additive genetics of the piglets, as they are expected to increase throughout lactation.}, number={11}, journal={JOURNAL OF ANIMAL SCIENCE}, publisher={American Society of Animal Science}, author={Putz, A. M. and Tiezzi, F. and Maltecca, C. and Gray, K. A. and Knauer, M. T.}, year={2015}, month={Nov}, pages={5153–5163} }
 @article{knauer_hostetler_2013, title={US swine industry productivity analysis, 2005 to 2010}, volume={21}, number={5}, journal={Journal of Swine Health and Production}, author={Knauer, M. T. and Hostetler, C. E.}, year={2013}, pages={248–252} }
 @article{knauer_cassady_newcom_see_2012, title={Gilt development traits associated with genetic line, diet and fertility}, volume={148}, ISSN={["1871-1413"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84863775012&partnerID=MN8TOARS}, DOI={10.1016/j.livsci.2012.05.024}, abstractNote={The objective was to associate gilt development traits with genetic line, diet and fertility group (FG). Gilts (n=1225) were reared from 162 to 265 days of age at a gilt development unit (GDU) and sent to sow farms. Females were Landrace (L), Large White (LW), L and LW F1 or L and LW composite. Estrous traits included age at puberty (AGEPUB), length of estrus (LOE), maximum strength of standing reflex with (MSRBOAR) or without (MSRNOBOAR) a boar present, total strength of standing reflex with (TSRBOAR) or without (TSRNOBOAR) a boar present, vulva redness (VR), strength of vulva reddening and swelling (VISUAL VULVA) and vulva width (VW). Growth and body composition traits were puberty weight, days to 114 kg and 10th rib backfat (BF) and loin muscle area (LMA) at 114 kg and puberty. Structural conformation traits included muscle mass, rib width, front leg side view, rear leg side view, front legs front view, rear legs rear view and locomotion (LOC). Sow farm entry traits were age, weight, BF and LMA. Sow traits included whether or not a gilt farrowed (STAY), age at first farrowing and total number born (TNB). Fertility groups were; FG0=did not reach puberty at the GDU (NOPUB), did not farrow (DNF); FG1=reached puberty at the GDU (YESPUB), DNF; FG2=NOPUB, farrowed; FG3=YESPUB, farrowed. Genetic lines differed (P<0.05) for estrous traits LOE, TSRBOAR, MSRNOBOAR, TSRNOBOAR, VR, VISUAL VULVA and VW. Females fed restrictively vs. ad libitum had a longer (P<0.05) LOE (2.18 vs. 2.03 d), higher (P<0.05) TSRBOAR (15.4 vs. 14.0) and younger (P<0.05) AGEPUB (219 vs. 225 d). Fertility groups 0, 1, 2 and 3 contained 45 (4%), 255 (24%), 66 (6%) and 698 (66%) gilts, respectively. Gilts from FG3 in comparison to FG1 had a longer (P<0.05) LOE (2.16 vs. 2.06 d), greater (P<0.05) MSRBOAR (7.6 vs. 7.4) and greater (P<0.05) TSRBOAR (15.4 vs. 14.6). Fertility group 0 had less (P<0.05) BF, poorer (P<0.05) LOC and was narrower (P<0.05) ribbed compared with the other FG's. Based on these results it was concluded that gilts with LOE ≤1 day or weak standing reflexes were less likely to farrow a litter.}, number={1-2}, journal={LIVESTOCK SCIENCE}, author={Knauer, M. T. and Cassady, J. P. and Newcom, D. W. and See, M. T.}, year={2012}, month={Sep}, pages={159–167} }
 @article{layman_knauer_stalder_karriker_mckean_serenius_baas_johnson_2009, title={Characterization of Lesions in U.S. Cull Sows}, volume={12}, ISSN={1088-8705 1532-7604}, url={http://dx.doi.org/10.1080/10888700902720359}, DOI={10.1080/10888700902720359}, abstractNote={Physical and reproductive conditions of 3,158 cull sows from 2 U.S. Midwestern harvest facilities were assessed. Body condition, feet, shoulders, teeth, lungs, and reproductive tracts were visually evaluated for gross lesions at harvest. Based on the observations of this study, body condition score (BCS) was associated with several abnormal conditions of sows. Foot-related lesions (overgrown toes, foot pad lesions) represented the most frequently documented lesions. Temporal associations of the interactions between lesions and BCS are unknown. Even though causal relations were not established by this study, the strong associations observed suggest that sows who do not respond to increased feeding with improved BCS could reasonably be expected to have additional lesions that may impact performance and welfare. On-farm management practices may be related to 1 or more lesions (including foot lesions) that had a high prevalence in this study. Farm management practices and nonhuman animal welfare could not be evaluated with this study so no extrapolation can be given to the type of animal housing or the antemortem behavior of these sows.}, number={2}, journal={Journal of Applied Animal Welfare Science}, publisher={Informa UK Limited}, author={Layman, Lori and Knauer, Mark and Stalder, Ken J. and Karriker, Locke A. and McKean, James and Serenius, Timo and Baas, Tom and Johnson, Colin}, year={2009}, month={Mar}, pages={152–152} }
 @article{knauer_stalder_karriker_baas_johnson_serenius_layman_mckean_2007, title={A descriptive survey of lesions from cull sows harvested at two Midwestern U.S. facilities}, volume={82}, ISSN={0167-5877}, url={http://dx.doi.org/10.1016/j.prevetmed.2007.05.017}, DOI={10.1016/j.prevetmed.2007.05.017}, abstractNote={Physical and reproductive conditions of cull sows (3158) from two U.S. Midwestern harvest plants were assessed. Body condition, feet, shoulders, teeth, lungs, and reproductive tracts were visually evaluated for gross lesions on harvested sows. PROC FREQ (SAS, Cary, NC) was used to calculate the frequency of each binary trait event. Pearson chi-square tests were used to test the alternative hypothesis that a linear association existed between binary traits and body condition score (BCS). The most common foot lesions observed were rear (n=2064, 67.5%) and front (n=1024, 32.9%) heel lesions. Cracked hooves were found on the front feet of 703 (22.6%) and rear feet of 552 (18.1%) sows. Rear digital overgrowth was observed in 644 (21.1%) sows. The most common reproductive gross lesion observed among harvested cull sows was acyclic ovaries (n=277, 9.0%). Presence of acyclic ovaries increased (p<0.01) as BCS decreased. Cystic ovaries were found in 192 (6.3%) sows, which increased (p<0.01) as BCS increased. Pneumonia was observed in 298 (9.7%) sows, and increased in frequency as BCS decreased (p<0.01). The most frequently observed shoulder lesion among harvested cull sows was shoulder abrasions (n=394, 12.5%). The presence of shoulder abrasions increased (p<0.01) as BCS decreased. The prevalence of reproductive lesions detected in the present study was less than the reported percentage of sows culled for reproductive failure from previous studies based on record keeping summaries.}, number={3-4}, journal={Preventive Veterinary Medicine}, publisher={Elsevier BV}, author={Knauer, M. and Stalder, K.J. and Karriker, L. and Baas, T.J. and Johnson, C. and Serenius, T. and Layman, L. and McKean, J.D.}, year={2007}, month={Dec}, pages={198–212} }