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RESEARCH ARTICLE

An attempt of using public ambient temperature data in swine genetic evaluation for litter-size traits at birth in Japan

Hitomi Hara A # , Shinichiro Ogawa https://orcid.org/0000-0002-0537-3311 A D # * , Chika Ohnishi B E , Kazuo Ishii C D , Yoshinobu Uemoto A and Masahiro Satoh A
+ Author Affiliations
- Author Affiliations

A Graduate School of Agricultural Science, Tohoku University, Sendai, Miyagi 980-8572, Japan.

B National Livestock Breeding Center, Miyazaki Station, Kobayashi, Miyazaki 886-0004, Japan.

C Division of Animal Breeding and Reproduction, Institute of Livestock and Grassland Science, NARO, Tsukuba, Ibaraki 305-0901, Japan.

D Present address: Division of Meat Animal and Poultry Research, Institute of Livestock and Grassland Science, NARO, Tsukuba, Ibaraki 305-0901, Japan.

E Present address: National Livestock Breeding Center, Okazaki Station, Okazaki, Aichi 444-3161, Japan.

* Correspondence to: ogawas897@affrc.go.jp
# These authors contributed equally to this paper

Handling Editor: John Gaughan

Animal Production Science 62(15) 1488-1500 https://doi.org/10.1071/AN21463
Submitted: 6 September 2021  Accepted: 12 April 2022   Published: 31 May 2022

© 2022 The Author(s) (or their employer(s)). Published by CSIRO Publishing

Abstract

Context: Large-scale genetic evaluation is promising for efficiently improving sow lifetime productivity, and therefore, a reasonable operational model should be pursued to analyse phenotypic data collected from around Japan, where unique seasonality exists. However, the information on establishing the model is currently insufficient.

Aims: To obtain the fundamental information on using ambient temperature information in developing the model for routine swine genetic evaluation in Japan, by analysing total number born, number born alive, and number stillborn collected at a Japanese farm, together with off-farm ambient temperature measured at the nearest Automated Meteorological Data Acquisition System station.

Methods: Five repeatability animal models were exploited, considering the effects of farrowing season (Model 1), farrowing month (Model 2), quadratic regressions of daily maximum ambient temperature of farrowing day (Model 3), season and temperature (Model 4), or month and temperature (Model 5).

Key results: Patterns of the effects of daily maximum temperature of farrowing day estimated using Model 3 were similar to those of farrowing season by Model 1 and those of farrowing month by Model 2. Adding the effect of daily maximum temperature of farrowing day (Models 4 and 5) could explain phenotypic variability better than only considering either of farrowing season or month (Models 1 and 2). Estimated heritability was stable among the models and the rank correlation of predicted breeding values among models was >0.98 for all traits.

Conclusions: The results indicated the possibility that using public ambient temperature can capture a large part of the phenotypic variability in litter-size traits at birth caused by seasonality in Japan.

Implications: This study could support the availability of public meteorological data in the development of flexible operational models for future swine genetic evaluation in Japan.

Keywords: genetic parameter estimation, heat, meteorological observation data, number born alive, number stillborn, on- and off-farm ambient temperature, pig breeding, season.


References

Bertoldo MJ, Holyoake PK, Evans G, Grupen CG (2012) Seasonal variation in the ovarian function of sows. Reproduction, Fertility and Development 24, 822–834.
Seasonal variation in the ovarian function of sows.Crossref | GoogleScholarGoogle Scholar |

Bloemhof S, van der Waaij EH, Merks JWM, Knol EF (2008) Sow line differences in heat stress tolerance expressed in reproductive performance traits. Journal of Animal Science 86, 3330–3337.
Sow line differences in heat stress tolerance expressed in reproductive performance traits.Crossref | GoogleScholarGoogle Scholar | 18708608PubMed |

Bloemhof S, Mathur PK, van der Waaij EH, Leenhouwers JI, Knol EF (2012) Genetic aspects of heat stress in pigs expressed in fertility traits. In ‘14 seminar of the FAO–CIHEAM subnetwork on sheep and goat nutrition and 2nd Lowinputbreeds symposium’, Hammamet, Tunesia, 15–18 May 2012. (CIHEAM-IAMZ; INRAT; OEP; IRESA; FAO)

Bloemhof S, Mathur PK, Knol EF, van der Waaij EH (2013) Effect of daily environmental temperature on farrowing rate and total born in dam line sows. Journal of Animal Science 91, 2667–2679.
Effect of daily environmental temperature on farrowing rate and total born in dam line sows.Crossref | GoogleScholarGoogle Scholar | 23482580PubMed |

Brown-Brandl TM, Eigenberg RA, Nienaber JA, Kachman SD (2001) Thermoregulatory profile of a newer genetic line of pigs. Livestock Production Science 71, 253–260.
Thermoregulatory profile of a newer genetic line of pigs.Crossref | GoogleScholarGoogle Scholar |

Cabezón FA, Schinckel AP, Richert BT, Stewart KR, Gandarillas M, Peralta WA (2016) Analysis of lactation feed intakes for sows including data on environmental temperatures and humidity. The Professional Animal Scientist 32, 333–345.
Analysis of lactation feed intakes for sows including data on environmental temperatures and humidity.Crossref | GoogleScholarGoogle Scholar |

Carabaño MJ, Ramón M, Menéndez-Buxadera A, Molina A, Díaz C (2019) Selecting for heat tolerance. Animal Frontiers 9, 62–68.
Selecting for heat tolerance.Crossref | GoogleScholarGoogle Scholar | 32002241PubMed |

Curtis SE (1983) ‘Environmental management in animal agriculture.’ pp. 6–96. (Iowa State University Press: Ames, IA, USA)

Edwards RL, Omtvedt IT, Tuesman EJ, Stephens DF, Mahoney GWA (1968) Reproductive performance of gilts following heat stress prior to breeding and in early gestation. Journal of Animal Science 27, 1634–1637.
Reproductive performance of gilts following heat stress prior to breeding and in early gestation.Crossref | GoogleScholarGoogle Scholar |

Flowers B, Day BN (1990) Alterations in gonadotropin secretion and ovarian function in prepubertal gilts by elevated environmental temperature. Biology of Reproduction 42, 465–471.
Alterations in gonadotropin secretion and ovarian function in prepubertal gilts by elevated environmental temperature.Crossref | GoogleScholarGoogle Scholar | 2111186PubMed |

Flowers B, Cantley TC, Martin MJ, Day BN (1989) Effect of elevated ambient temperatures on puberty in gilts. Journal of Animal Science 67, 779–784.
Effect of elevated ambient temperatures on puberty in gilts.Crossref | GoogleScholarGoogle Scholar | 2722706PubMed |

Fragomeni BO, Lourenco DAL, Tsuruta S, Andonov S, Gray K, Huang Y, Misztal I (2016a) Modeling response to heat stress in pigs from nucleus and commercial farms in different locations in the United States. Journal of Animal Science 94, 4789–4798.
Modeling response to heat stress in pigs from nucleus and commercial farms in different locations in the United States.Crossref | GoogleScholarGoogle Scholar | 27898949PubMed |

Fragomeni BO, Lourenco DAL, Tsuruta S, Bradford HL, Gray KA, Huang Y, Misztal I (2016b) Using single-step genomic best linear unbiased predictor to enhance the mitigation of seasonal losses due to heat stress in pigs. Journal of Animal Science 94, 5004–5013.
Using single-step genomic best linear unbiased predictor to enhance the mitigation of seasonal losses due to heat stress in pigs.Crossref | GoogleScholarGoogle Scholar | 28046178PubMed |

Freitas MS, Misztal I, Bohmanova J, West J (2006) Utility of on- and off-farm weather records for studies in genetics of heat tolerance. Livestock Science 105, 223–228.
Utility of on- and off-farm weather records for studies in genetics of heat tolerance.Crossref | GoogleScholarGoogle Scholar |

Fujimoto K, Kawasaki M, Endo Y, Yokoyama T, Yamane I, Yamazaki H, Kure K, Haga T, Sugiura K (2021) Antimicrobial use on 74 Japanese pig farms in 2019: a comparison of Japanese and European defined daily doses in the field. PLoS ONE 16, e0255632
Antimicrobial use on 74 Japanese pig farms in 2019: a comparison of Japanese and European defined daily doses in the field.Crossref | GoogleScholarGoogle Scholar | 34358280PubMed |

Guy SZY, Li L, Thomson PC, Hermesch S (2017) Contemporary group estimates adjusted for climatic effects provide a finer definition of the unknown environmental challenges experienced by growing pigs. Journal of Animal Breeding and Genetics 134, 520–530.
Contemporary group estimates adjusted for climatic effects provide a finer definition of the unknown environmental challenges experienced by growing pigs.Crossref | GoogleScholarGoogle Scholar | 28691230PubMed |

Harada K, Komura H, Duran PG, Ochiai I, Fukuhara R (1992) Effects of fattening season on the growth pattern and estimated mature size of ultrasonic estimates of carcass traits in live pigs. Animal Science and Technology 63, 1042–1050.
Effects of fattening season on the growth pattern and estimated mature size of ultrasonic estimates of carcass traits in live pigs.Crossref | GoogleScholarGoogle Scholar |

Hill WG (2016) Is continued genetic improvement of livestock sustainable? Genetics 202, 877–881.
Is continued genetic improvement of livestock sustainable?Crossref | GoogleScholarGoogle Scholar | 26953266PubMed |

Iida R, Koketsu Y (2013) Quantitative associations between outdoor climate data and weaning-to-first-mating interval or adjusted 21-day litter weights during summer in Japanese swine breeding herds. Livestock Science 152, 253–260.
Quantitative associations between outdoor climate data and weaning-to-first-mating interval or adjusted 21-day litter weights during summer in Japanese swine breeding herds.Crossref | GoogleScholarGoogle Scholar |

Iida R, Koketsu Y (2014a) Climatic factors associated with peripartum pig deaths during hot and humid or cold seasons. Preventive Veterinary Medicine 115, 166–172.
Climatic factors associated with peripartum pig deaths during hot and humid or cold seasons.Crossref | GoogleScholarGoogle Scholar | 24785123PubMed |

Iida R, Koketsu Y (2014b) Interactions between pre- or postservice climatic factors, parity, and weaning-to-first-mating interval for total number of pigs born of female pigs serviced during hot and humid or cold seasons. Journal of Animal Science 92, 4180–4188.
Interactions between pre- or postservice climatic factors, parity, and weaning-to-first-mating interval for total number of pigs born of female pigs serviced during hot and humid or cold seasons.Crossref | GoogleScholarGoogle Scholar | 25023804PubMed |

Johnson JS (2018) Heat stress: impact on livestock well-being and productivity and mitigation strategies to alleviate the negative effects. Animal Production Science 58, 1404–1413.
Heat stress: impact on livestock well-being and productivity and mitigation strategies to alleviate the negative effects.Crossref | GoogleScholarGoogle Scholar |

Johnson JS, Zhang S, Morello GM, Maskal JM, Trottier NL (2019) Technical note: development of an indirect calorimetry system to determine heat production in individual lactating sows. Journal of Animal Science 97, 1609–1618.
Technical note: development of an indirect calorimetry system to determine heat production in individual lactating sows.Crossref | GoogleScholarGoogle Scholar | 30753504PubMed |

Kadowaki H, Suzuki E, Kojima-Shibata C, Suzuki K, Okamura T, Onodera W, Shibata T, Kano H (2012) Selection for resistance to swine mycoplasmal pneumonia over 5 generations in Landrace pigs. Livestock Science 147, 20–26.
Selection for resistance to swine mycoplasmal pneumonia over 5 generations in Landrace pigs.Crossref | GoogleScholarGoogle Scholar |

Kadowaki K, Osawa T, Ishii K, Inoue K (2019) Estimates of genetic parameters for number born alive using a random regression model with considered parities. Japanese Journal of Swine Science 56, 139–148.
Estimates of genetic parameters for number born alive using a random regression model with considered parities.Crossref | GoogleScholarGoogle Scholar |

Kakuma T (2018) Seasonal effects on the pig farm management. Japanese Journal of Swine Science 55, 48–55.
Seasonal effects on the pig farm management.Crossref | GoogleScholarGoogle Scholar |

Kim SW, Weaver AC, Shen YB, Zhao Y (2013) Improving efficiency of sow productivity: nutrition and health. Journal of Animal Science and Biotechnology 4, 26
Improving efficiency of sow productivity: nutrition and health.Crossref | GoogleScholarGoogle Scholar | 23885840PubMed |

Klei B, Tsuruta S (2008) Approximate variance for heritability estimates. Available at http://nce.ads.uga.edu/∼shogo/html/research/AI_SE.pdf [Accessed 21 May 2020]

Koike N, Mai TN, Shirai M, Kubo M, Hata K, Marumoto N, Watanabe S, Sasaki Y, Mitoma S, Notsu K, Okabayashi T, Wiratsudakul A, Kabali E, Norimine J, Sekiguchi S (2018) Detection of neutralizing antibody against porcine epidemic diarrhea virus in subclinically infected finishing pigs. Journal of Veterinary Medical Science 80, 1782–1786.
Detection of neutralizing antibody against porcine epidemic diarrhea virus in subclinically infected finishing pigs.Crossref | GoogleScholarGoogle Scholar | 30282841PubMed |

Konta A, Ogawa S, Kimata M, Ishii K, Uemoto Y, Satoh M (2019) A study on the potential for improving number born alive using teat number in pig female breeds. Nihon Chikusan Gakkaiho 90, 207–212.
A study on the potential for improving number born alive using teat number in pig female breeds.Crossref | GoogleScholarGoogle Scholar |

Konta A, Ogawa S, Kimata M, Ishii K, Uemoto Y, Satoh M (2020) Comparison of two models to estimate genetic parameters for number of born alive in pigs. Animal Science Journal 91, e13417
Comparison of two models to estimate genetic parameters for number of born alive in pigs.Crossref | GoogleScholarGoogle Scholar | 32662131PubMed |

Lewis CRG, Bunter KL (2011) Effects of seasonality and ambient temperature on genetic parameters for production and reproductive traits in pigs. Animal Production Science 51, 615–626.
Effects of seasonality and ambient temperature on genetic parameters for production and reproductive traits in pigs.Crossref | GoogleScholarGoogle Scholar |

Malmkvist J, Pedersen LJ, Damgaard BM, Thodberg K, Jorgensen E, Labouriau R (2006) Does floor heating around parturition affect the vitality of piglets born to loose housed sows? Applied Animal Behaviour Science 99, 88–105.
Does floor heating around parturition affect the vitality of piglets born to loose housed sows?Crossref | GoogleScholarGoogle Scholar |

Manno MC, Oliveira RFMd, Donzele JL, Ferreira AS, Oliveira WPd, Lima KRdS, Vaz RGMV (2005) Effect of thermal environment on performance of growing pigs from 15 to 30 kg. Revista Brasileira de Zootecnia 34, 1963–1970.
Effect of thermal environment on performance of growing pigs from 15 to 30 kg.Crossref | GoogleScholarGoogle Scholar |

Mayorga EJ, Renaudeau D, Ramirez BC, Ross JW, Baumgard LH (2019) Heat stress adaptations in pigs. Animal Frontiers 9, 54–61.
Heat stress adaptations in pigs.Crossref | GoogleScholarGoogle Scholar | 32002240PubMed |

Mellado M, Gaytán L, Macías-Cruz U, Avendaño L, Meza-Herrera C, Lozano EA, Rodríguez Á, Mellado J (2018) Effect of climate and insemination technique on reproductive performance of gilts and sows in a subtropical zone of Mexico. Austral Journal of Veterinary Sciences 50, 27–34.
Effect of climate and insemination technique on reproductive performance of gilts and sows in a subtropical zone of Mexico.Crossref | GoogleScholarGoogle Scholar |

Melzer N, Wittenburg D, Repsilber D (2013) Integrating milk metabolite profile information for the prediction of traditional milk traits based on SNP information for Holstein cows. PLoS ONE 8, e70256
Integrating milk metabolite profile information for the prediction of traditional milk traits based on SNP information for Holstein cows.Crossref | GoogleScholarGoogle Scholar | 23990900PubMed |

Merks JWM (2000) One century of genetic changes in pigs and the future needs. BSAP Occasional Publication 27, 8–19.
One century of genetic changes in pigs and the future needs.Crossref | GoogleScholarGoogle Scholar |

Misztal I, Tsuruta S, Strabel T, Auvray B, Druet T, Lee DH (2002) BLUPF90 and related programs. In ‘Proceedings of the 7th world congress of genetics applied to livestock production, Montpellier, France’.

Mount LE (1959) The metabolic rate of the new-born pig in relation to environmental temperature and to age. The Journal of Physiology 147, 333–345.
The metabolic rate of the new-born pig in relation to environmental temperature and to age.Crossref | GoogleScholarGoogle Scholar | 14424736PubMed |

Nardone A, Ronchi B, Lacetera N, Bernabucci U (2006) Climatic effects on productive traits in livestock. Veterinary Research Communications 30, 75–81.
Climatic effects on productive traits in livestock.Crossref | GoogleScholarGoogle Scholar |

Ogawa S, Matsuda H, Taniguchi Y, Watanabe T, Takasuga A, Sugimoto Y, Iwaisaki H (2015) Estimated genetic variances due to QTL candidate regions for carcass traits in Japanese Black cattle. In ‘Book of abstracts of the 66th annual meeting of the European Association for animal production’, Warsaw, Poland. (EAAP Scientific Committee, Wageningen Academic Publishers)

Ogawa S, Konta A, Kimata M, Ishii K, Uemoto Y, Satoh M (2019a) Estimation of genetic parameters for farrowing traits in purebred Landrace and Large White pigs. Animal Science Journal 90, 23–28.
Estimation of genetic parameters for farrowing traits in purebred Landrace and Large White pigs.Crossref | GoogleScholarGoogle Scholar | 30370591PubMed |

Ogawa S, Konta A, Kimata M, Ishii K, Uemoto Y, Satoh M (2019b) Genetic parameter estimation for number born alive at different parities in Landrace and Large White pigs. Animal Science Journal 90, 1111–1119.
Genetic parameter estimation for number born alive at different parities in Landrace and Large White pigs.Crossref | GoogleScholarGoogle Scholar | 31270928PubMed |

Ogawa S, Konta A, Kimata M, Ishii K, Uemoto Y, Satoh M (2019c) Genetic relationship of litter traits between farrowing and weaning in Landrace and Large White pigs. Animal Science Journal 90, 1510–1516.
Genetic relationship of litter traits between farrowing and weaning in Landrace and Large White pigs.Crossref | GoogleScholarGoogle Scholar | 31625251PubMed |

Ogawa S, Ohnishi C, Ishii K, Uemoto Y, Satoh M (2020) Genetic relationship between litter size traits at birth and body measurement and production traits in purebred Duroc pigs. Animal Science Journal 91, e13497
Genetic relationship between litter size traits at birth and body measurement and production traits in purebred Duroc pigs.Crossref | GoogleScholarGoogle Scholar | 33368835PubMed |

Ogawa S, Kimata M, Ishii K, Uemoto Y, Satoh M (2021a) Genetic analysis for sow stayability at different parities in purebred Landrace and Large White pigs. Animal Science Journal 92, e13599
Genetic analysis for sow stayability at different parities in purebred Landrace and Large White pigs.Crossref | GoogleScholarGoogle Scholar | 34309970PubMed |

Ogawa S, Yazaki N, Ohnishi C, Ishii K, Uemoto Y, Satoh M (2021b) Maternal effect on body measurement and meat production traits in purebred Duroc pigs. Journal of Animal Breeding and Genetics 138, 237–245.
Maternal effect on body measurement and meat production traits in purebred Duroc pigs.Crossref | GoogleScholarGoogle Scholar | 32949477PubMed |

Ohnishi C, Satoh M (2018) Estimation of genetic parameters for performance and body measurement traits in Duroc pigs selected for average daily gain, loin muscle area, and backfat thickness. Livestock Science 214, 161–166.
Estimation of genetic parameters for performance and body measurement traits in Duroc pigs selected for average daily gain, loin muscle area, and backfat thickness.Crossref | GoogleScholarGoogle Scholar |

Okada D, Endo S, Matsuda H, Ogawa S, Taniguchi Y, Katsuta T, Watanabe T, Iwaisaki H (2018) An intersection network based on combining SNP coassociation and RNA coexpression networks for feed utilization traits in Japanese Black cattle. Journal of Animal Science 96, 2553–2566.
An intersection network based on combining SNP coassociation and RNA coexpression networks for feed utilization traits in Japanese Black cattle.Crossref | GoogleScholarGoogle Scholar | 29762780PubMed |

Omtvedt IT, Nelson RE, Edwards RL, Stephens DF, Turman EJ (1971) Influence of heat stress during early, mid and late pregnancy of gilts. Journal of Animal Science 32, 312–317.
Influence of heat stress during early, mid and late pregnancy of gilts.Crossref | GoogleScholarGoogle Scholar | 5543028PubMed |

Pandorfi H, da Silva IJO, de Moura DJ, Sevegnani KB (2005) Microclima de abrigos escamoteadores para leitões submetidos a diferentes sistemas de aquecimento no período de inverno. Revista Brasileira de Engenharia Agrícola e Ambiental 9, 99–106.
Microclima de abrigos escamoteadores para leitões submetidos a diferentes sistemas de aquecimento no período de inverno.Crossref | GoogleScholarGoogle Scholar |

Peltoniemi OAT, Love RJ, Heinonen M, Tuovinen V, Saloniemi H (1999) Seasonal and management effects on fertility of the sow: a descriptive study. Animal Reproduction Science 55, 47–61.
Seasonal and management effects on fertility of the sow: a descriptive study.Crossref | GoogleScholarGoogle Scholar |

Quesnel H, Pasquier A, Mounier AM, Prunier A (1998) Influence of feed restriction during lactation on gonadotropic hormones and ovarian development in primiparous sows. Journal of Animal Science 76, 856–863.
Influence of feed restriction during lactation on gonadotropic hormones and ovarian development in primiparous sows.Crossref | GoogleScholarGoogle Scholar | 9535348PubMed |

Rauw WM, de Mercado de la Peña E, Gomez-Raya L, Cortés LAG, Ciruelos JJ, Izquierdo EG (2020) Impact of environmental temperature on production traits in pigs. Scientific Reports 10, 2106
Impact of environmental temperature on production traits in pigs.Crossref | GoogleScholarGoogle Scholar | 32034216PubMed |

Renaudeau D, Gourdine JL, St-Pierre NR (2011) A meta-analysis of the effects of high ambient temperature on growth performance of growing-finishing pigs. Journal of Animal Science 89, 2220–2230.
A meta-analysis of the effects of high ambient temperature on growth performance of growing-finishing pigs.Crossref | GoogleScholarGoogle Scholar | 21297065PubMed |

Robbins LA, Green-Miller AR, Lay DC, Schinckel AP, Johnson JS, Gaskill BN (2021) Evaluation of sow thermal preference across three stages of reproduction. Journal of Animal Science 99, skab202
Evaluation of sow thermal preference across three stages of reproduction.Crossref | GoogleScholarGoogle Scholar | 34197578PubMed |

Saito H, Koketsu Y (2009) Factors associated with an occurrence of decreased pigs born alive in parity 2 in commercial herds. Journal of Veterinary Epidemiology 13, 40–45.
Factors associated with an occurrence of decreased pigs born alive in parity 2 in commercial herds.Crossref | GoogleScholarGoogle Scholar |

Sakatani M (2014) Effects of summer heat stress on domestic animals. Japanese Journal of Large Animal Clinics 5, 238–246.
Effects of summer heat stress on domestic animals.Crossref | GoogleScholarGoogle Scholar |

Sasaki Y, Fujie M, Nakatake S, Kawabata T (2018) Quantitative assessment of the effects of outside temperature on farrowing rate in gilts and sows by using a multivariate logistic regression model. Animal Science Journal 89, 1187–1193.
Quantitative assessment of the effects of outside temperature on farrowing rate in gilts and sows by using a multivariate logistic regression model.Crossref | GoogleScholarGoogle Scholar | 29808521PubMed |

Schauberger G, Mikovits C, Zollitsch W, Hörtenhuber SJ, Baumgartner J, Niebuhr K, Piringer M, Knauder W, Anders I, Andre K, Hennig-Pauka I, Schönhart M (2019) Global warming impact on confined livestock in buildings: efficacy of adaptation measures to reduce heat stress for growing-fattening pigs. Climatic Change 156, 567–587.
Global warming impact on confined livestock in buildings: efficacy of adaptation measures to reduce heat stress for growing-fattening pigs.Crossref | GoogleScholarGoogle Scholar |

Suzuki K, Kadowaki H, Shibata T, Uchida H, Nishida A (2005) Selection for daily gain, loin-eye area, backfat thickness and intramuscular fat based on desired gains over seven generations of Duroc pigs. Livestock Production Science 97, 193–202.
Selection for daily gain, loin-eye area, backfat thickness and intramuscular fat based on desired gains over seven generations of Duroc pigs.Crossref | GoogleScholarGoogle Scholar |

Takada R, Yamazaki M, Sugiura T, Yokozawa M, Otsuka M, Murakami H (2008) Future prediction of the effect of global warming on a pig growth performance estimated from changes of the mean ambient temperature. Nihon Chikusan Gakkaiho 79, 59–65.
Future prediction of the effect of global warming on a pig growth performance estimated from changes of the mean ambient temperature.Crossref | GoogleScholarGoogle Scholar |

Tiezzi F, Brito LF, Howard J, Huang YJ, Gray K, Schwab C, Fix J, Maltecca C (2020) Genomics of heat tolerance in reproductive performance investigated in four independent maternal lines of pigs. Frontiers in Genetics 11, 629
Genomics of heat tolerance in reproductive performance investigated in four independent maternal lines of pigs.Crossref | GoogleScholarGoogle Scholar | 32695139PubMed |

Tomiyama M, Kubo S, Takagi T, Suzuki K (2011) Evaluation of genetic trends and determination of the optimal number of cumulative records of parity required in reproductive traits in a Large White pig population. Animal Science Journal 82, 621–626.
Evaluation of genetic trends and determination of the optimal number of cumulative records of parity required in reproductive traits in a Large White pig population.Crossref | GoogleScholarGoogle Scholar | 21951897PubMed |

Tuchscherer M, Puppe B, Tuchscherer A, Tiemann U (2000) Early identification of neonates at risk: traits of newborn piglets with respect to survival. Theriogenology 54, 371–388.
Early identification of neonates at risk: traits of newborn piglets with respect to survival.Crossref | GoogleScholarGoogle Scholar | 11051321PubMed |

Tummaruk P (2012) Effects of season, outdoor climate and photo period on age at first observed estrus in Landrace × Yorkshire crossbred gilts in Thailand. Livestock Science 144, 163–172.
Effects of season, outdoor climate and photo period on age at first observed estrus in Landrace × Yorkshire crossbred gilts in Thailand.Crossref | GoogleScholarGoogle Scholar |

Tummaruk P, Tantasuparuk W, Techakumphu M, Kunavongkrit A (2004) Effect of season and outdoor climate on litter size at birth in purebred Landrace and Yorkshire sows in Thailand. Journal of Veterinary Medical Science 66, 477–482.
Effect of season and outdoor climate on litter size at birth in purebred Landrace and Yorkshire sows in Thailand.Crossref | GoogleScholarGoogle Scholar | 15187355PubMed |

Tummaruk P, Tantasuparuk W, Techakumphu M, Kunavongkrit A (2010) Seasonal influences on the litter size at birth of pigs are more pronounced in the gilt than sow litters. The Journal of Agricultural Science 148, 421–432.
Seasonal influences on the litter size at birth of pigs are more pronounced in the gilt than sow litters.Crossref | GoogleScholarGoogle Scholar |

Usala M, Macciotta NPP, Bergamaschi M, Maltecca C, Fix J, Schwab C, Shull C, Tiezzi F (2021) Genetic parameters for tolerance to heat stress in crossbred swine carcass traits. Frontiers in Genetics 11, 612815
Genetic parameters for tolerance to heat stress in crossbred swine carcass traits.Crossref | GoogleScholarGoogle Scholar | 33613622PubMed |

Wegner K, Lambertz C, Daş G, Reiner G, Gauly M (2014) Climatic effects on sow fertility and piglet survival under influence of a moderate climate. Animal 8, 1526–1533.
Climatic effects on sow fertility and piglet survival under influence of a moderate climate.Crossref | GoogleScholarGoogle Scholar | 24846319PubMed |

Wegner K, Lambertz C, Das G, Reiner G, Gauly M (2016) Effects of temperature and temperature–humidity index on the reproductive performance of sows during summer months under a temperate climate. Animal Science Journal 87, 1334–1339.
Effects of temperature and temperature–humidity index on the reproductive performance of sows during summer months under a temperate climate.Crossref | GoogleScholarGoogle Scholar | 26989052PubMed |

Wildt DE, Riegle GD, Dukelow WR (1975) Physiological temperature response and embryonic mortality in stressed swine. American Journal of Physiology-Legacy Content 229, 1471–1475.
Physiological temperature response and embryonic mortality in stressed swine.Crossref | GoogleScholarGoogle Scholar |

Yan P, Yamamoto S (2000) Relationships between thermoregulatory responses and heat loss in piglets. Nihon Chikusan Gakkaiho 71, 505–509.
Relationships between thermoregulatory responses and heat loss in piglets.Crossref | GoogleScholarGoogle Scholar |

Yazaki N, Ogawa S, Ohnishi C, Ishii K, Uemoto Y, Satoh M (2020) Effectiveness of body measurement traits for improving production traits in Duroc pigs. Nihon Chikusan Gakkaiho 91, 9–16.
Effectiveness of body measurement traits for improving production traits in Duroc pigs.Crossref | GoogleScholarGoogle Scholar |

Zak LJ, Gaustad AH, Bolarin A, Broekhuijse MLWJ, Walling GA, Knol EF (2017) Genetic control of complex traits, with a focus on reproduction in pigs. Molecular Reproduction and Development 84, 1004–1011.
Genetic control of complex traits, with a focus on reproduction in pigs.Crossref | GoogleScholarGoogle Scholar | 28792084PubMed |

Zumbach B, Misztal I, Tsuruta S, Sanchez JP, Azain M, Herring W, Holl J, Long T, Culbertson M (2008) Genetic components of heat stress in finishing pigs: development of a heat load function. Journal of Animal Science 86, 2082–2088.
Genetic components of heat stress in finishing pigs: development of a heat load function.Crossref | GoogleScholarGoogle Scholar | 18469060PubMed |