Animal Reproduction (AR)
https://animal-reproduction.org/article/doi/10.1590/1984-3143-AR2024-0087
Animal Reproduction (AR)
REVIEW ARTICLE

Too late or too soon? The replacement gilt paradox

Thomaz Lucia Junior

Downloads: 0
Views: 88

Abstract

Due to high annual culling rates, pig farms require a constant income of replacement gilts. Gilts typically reach puberty at nearly six months of age. Puberty may be induced through early boar exposure, therapy with steroid hormones and chorionic gonadotropins, and optimized by identifying biological predictors and risk factors. Old age at the time of the first mating is associated with an increased risk of premature culling, often attributed to reproductive failures and locomotor problems. While female prolifacy has increased substantially during the last few decades, selecting for litter size to optimize lifetime productivity would be more efficient after two parities. Additionally, uterine capacity and the number of functional teats should be considered in selecting future dams. For each female, the cost-effective number of parities at removal is determined by the cumulative number of pigs born and weaned during the total herd days.

Keywords

gilt, puberty, litter size, reproductive failures, removal, lifetime productivity

References

Agriness® [Internet]. 2023 [cited 2023 Dec 2]. Available from: http://www.agriness.com

Ahlström S, Jarvis S, Lawrence AB. Savaging gilts are more restless and more responsive to piglets during the expulsive phase of parturition. Appl Anim Behav Sci. 2002;76(1):83-91. http://doi.org/10.1016/S0168-1591(01)00207-6.

Alexopoulos JG, Lines DS, Hallett S, Plush KJ. A review of success factors for piglet fostering in lactation. Animals. 2018;8(3):38. http://doi.org/10.3390/ani8030038. PMid:29522470.

Almeida FRCL, Alvarenga Dias ALN, Moreira LP, Fiúza ATL, Chiarini-Garcia H. Ovarian follicle development and genital tract characteristics in different birthweight gilts at 150 days of age. Reprod Domest Anim. 2017a;52(5):756-62. http://doi.org/10.1111/rda.12976. PMid:28432701.

Almeida FRCL, Laurenssen B, Pereira LX, Teerds KJ, Soede NM. Effects of birthweight on reproductive system development and onset of puberty in gilts. Reprod Fertil Dev. 2017b;29(2):254-61. http://doi.org/10.1071/RD15036. PMid:26178740.

Alvarenga ALN, Chiarini-Garcia H, Cardeal PC, Moreira LP, Foxcroft GR, Fontes DO, Almeida FRCL. Intra-uterine growth retardation affects birth weight and postnatal development in pigs, impairing muscle accretion, duodenal mucosa morphology and carcass traits. Reprod Fertil Dev. 2013;25(2):387-95. http://doi.org/10.1071/RD12021. PMid:22995207.

Bailey DW, Dunlap KA, Frank JW, Erikson DW, White BG, Bazer FW, Burghardt RC, Johnson GA. Effects of long-term progesterone on developmental and functional aspects of porcine uterine epithelia and vasculature: progesterone alone does not support development of uterine glands comparable to that of pregnancy. Reproduction. 2010;140(4):583-94. http://doi.org/10.1530/REP-10-0170. PMid:20634388.

Baldessar P, Brito CRC, Johann H, Schultz C, Peripolli V, Moreira F, Lucia T Jr, Ulguim RR, Gasperin BG, Bianchi I. Long-acting injectable progesterone treatment prior to puberty induction in gilts. Domest Anim Endocrinol. 2023;84-85:106807. http://doi.org/10.1016/j.domaniend.2023.106807. PMid:37364520.

Barb CR, Hausman GJ, Lents CA. Energy metabolism and leptin: effects on neuroendocrine regulation of reproduction in the gilt and sow. Reprod Domest Anim. 2008;43(Suppl 2):324-30. http://doi.org/10.1111/j.1439-0531.2008.01173.x. PMid:18638142.

Batista EOS, Macedo GG, Sala RV, Ortolan MDDV, Sá MF Fo, del Valle TA, Jesus EF, Lopes RNVR, Renno FP, Baruselli PS. Plasma anti-Mullerian hormone as a predictor of ovarian antral follicular population in Bos indicus (Nelore) and Bos taurus (Holstein) heifers. Reprod Domest Anim. 2014;49(3):448-52. http://doi.org/10.1111/rda.12304. PMid:24689827.

Baxter EM, Rutherford KMD, D’eath RB, Arnott G, Turner SP, Sandøe P, Moustsen VA, Thorup F, Edwards SA, Lawrence AB. The welfare implications of large litter size in the domestic pig II: management factors. Anim Welf. 2013;22(2):219-38. http://doi.org/10.7120/09627286.22.2.219.

Beltranena E, Aherne FX, Foxcroft GR, Kirkwood RN. Effects of pre and postpubertal feeding on production traits at first and second estrus in gilts. J Anim Sci. 1991;69(3):886-93. http://doi.org/10.2527/1991.693886x. PMid:2061258.

Bhatia V, Stevens T, Derks MFL, Dunkelberger J, Knol EF, Ross JW, Dekkers JCM. Identification of the genetic basis of sow pelvic organ prolapse. Front Genet. 2023;14:1154713. http://doi.org/10.3389/fgene.2023.1154713. PMid:37144137.

Bhaumik S, Lockett J, Cuffe J, Clifton VL. Glucocorticoids and their receptor isoforms: roles in female reproduction, pregnancy, and foetal development. Biology. 2023;12(8):1104. http://doi.org/10.3390/biology12081104. PMid:37626990.

Blüher B, Mantzoros CS. Leptin in reproduction. Curr Opin Endocrinol Diabetes Obes. 2007;14(6):458-64. http://doi.org/10.1097/MED.0b013e3282f1cfdc. PMid:17982352.

Bó GA, de la Mata JJ, Baruselli PS, Menchaca A. Alternative programs for synchronizing and resynchronizing ovulation in beef cattle. Theriogenology. 2016;86(1):388-96. http://doi.org/10.1016/j.theriogenology.2016.04.053. PMid:27180326.

Bohrer BM, Flowers WL, Kyle JM, Johnson SS, King VL, Spruill JL, Thompson DP, Schroeder AL, Boler DD. Effect of gonadotropin releasing factor suppression with an immunological on growth performance, estrus activity, carcass characteristics, and meat quality of market gilts. J Anim Sci. 2014;92(10):4719-24. http://doi.org/10.2527/jas.2014-7756. PMid:25149345.

Bonneau M, Weiler U. Pros and cons of alternatives to piglet castration: welfare, boar taint, and other meat quality traits. Animals. 2019;9(11):884. http://doi.org/10.3390/ani9110884. PMid:31671665.

Borges VF, Bernardi ML, Bortolozzo FP, Wentz I. Risk factors for stillbirth and foetal mummification in four Brazilian swine herds. Prev Vet Med. 2005;70(3-4):165-76. http://doi.org/10.1016/j.prevetmed.2005.03.003. PMid:16023524.

Bortolozzo FP, Zanin GP, Ulguim RR, Mellagi APG. Managing reproduction in hyperprolific sow herds. Animals. 2023;13(11):1842. http://doi.org/10.3390/ani13111842. PMid:37889779.

Breen SM, Farris KL, Rodriguez-Zas SL, Knox RV. Effect of age and physical or fence-line boar exposure on estrus and ovulation response in prepubertal gilts administered PG600. J Anim Sci. 2005;83(2):460-5. http://doi.org/10.2527/2005.832460x. PMid:15644520.

Brito CRC, Cordeiro AD, Baldessar P, Schultz C, Quirino M, Ulguim RR, Gonçalves PBD, Lucia T Jr, Bianchi I, Gasperin BG. Reproductive performance in gilts submitted to non-steroidal therapies to prolong the luteal phase of the estrous cycle. Domest Anim Endocrinol. 2024;86:106821. http://doi.org/10.1016/j.domaniend.2023.106821. PMid:37944203.

Chen C, Gilbert CL, Yang G, Guo Y, Segonds-Pichon A, Ma J, Evans G, Brenig B, Sargent C, Affara N, Huang L. Maternal infanticide in sows: incidence and behavioural comparisons between savaging and non-savaging sows at parturition. Appl Anim Behav Sci. 2008;109(2-4):238-48. http://doi.org/10.1016/j.applanim.2007.02.008.

Christenson RK, Ford JJ, Redmer DA. Maturation of ovarian follicles in the prepubertal gilt. J Reprod Fertil Suppl. 1985;33:21-36. PMid:3936924.

Cordeiro AD, Conterato AJB, Bianchi I, Dartora DLA, Zanella R, Bondan C, Marques MG, Gasperin BG, Lucia T Jr. Successful lactation induction in non-pregnant gilts. Reprod Domest Anim. 2023;58(6):888-92. http://doi.org/10.1111/rda.14348. PMid:36961393.

Corezzolla JL, Ulguim RR, Gasperin BG, Rauber LP, Bianchi I. Altrenogest treatment effects on the reproductive performance of sows during transition to batch farrowing. Cienc Rural. 2020;50(9):e20190806. http://doi.org/10.1590/0103-8478cr20190806.

Craig JR, Collins CL, Bunter KL, Cottrell JJ, Dunshea FR, Pluske JR. Poorer lifetime growth performance of gilt progeny compared with sow progeny is largely due to weight differences at birth and reduced growth in the preweaning period and is not improved by progeny segregation after weaning. J Anim Sci. 2017;95(11):4904-16. http://doi.org/10.2527/jas2017.1868. PMid:29293711.

Daza A, Latorre MA, Olivares A, Lopez-Bote CJ. The effect of immunocastration and a diet based on granulated barley on growth performance and carcass, meat and fat quality in heavy gilts. Animal. 2014;8(3):484-93. http://doi.org/10.1017/S1751731113002292. PMid:24398015.

de la Cruz-Vigo P, Rodriguez-Boñal A, Rodriguez-Bonilla A, Córdova-Izquierdo A, Pérez Garnelo SS, Gómez-Fidalgo E, Martín-Lluch M, Sánchez-Sánchez R. Morphometric changes on the vulva from proestrus to oestrus of nulliparous and multiparous hyperprolific sows. Reprod Domest Anim. 2022;57(Suppl 5, Suppl 5):94-7. http://doi.org/10.1111/rda.14178. PMid:35689465.

Declerck I, Dewulf J, Sarrazin S, Maes D. Long-term effects of colostrum intake in piglet mortality and performance. J Anim Sci. 2016;94(4):1633-43. http://doi.org/10.2527/jas.2015-9564. PMid:27136022.

Devillers N, Farmer C, Mounier AM, le Dividich J, Prunier A. Hormones, IgG and lactose changes around parturition in plasma, and colostrum or saliva of multiparous sows. Reprod Nutr Dev. 2004;44(4):381-96. http://doi.org/10.1051/rnd:2004043. PMid:15535470.

Devillers N, le Dividich J, Prunier A. Influence of colostrum intake on piglet survival and immunity. Animal. 2011;5(10):1605-12. http://doi.org/10.1017/S175173111100067X. PMid:22440352.

Dial GD, Marsh WE, Polson DD, Vaillancourt J-P. Reproductive failure. In: Leman AD, Straw BE, Mengeling WL, D’Allaire S, Taylor DJ, editors. Diseases of swine. 7th ed. Ames: Iowa State University Press; 1992. p. 88-137.

Drake A, Fraser D, Weary DM. Parent-offspring resource allocation in domestic pigs. Behav Ecol Sociobiol. 2008;62(3):309-19. http://doi.org/10.1007/s00265-007-0418-y.

Easley DC, Abramowitch SA, Moalli PA. Female pelvic floor biomechanics: bridging the gap. Curr Opin Urol. 2017;27(3):262-7. http://doi.org/10.1097/MOU.0000000000000380. PMid:28267057.

Engblom L, Lundeheim N, Dalin AM, Andersson K. Sow removal in Swedish commercial herds. Livest Sci. 2007;106(1):76-86. http://doi.org/10.1016/j.livsci.2006.07.002.

Estienne MJ, Crawford RJ. Characteristics of estrous cycles in gilts treated with gonadotropins after estrus or treatment with a progestogen. Theriogenology. 2015;83(4):459-65. http://doi.org/10.1016/j.theriogenology.2014.03.004. PMid:25498519.

Evans ACO, O’Doherty JV. Endocrine changes and management factors affecting puberty in gilts. Livest Prod Sci. 2001;68(1):1-12. http://doi.org/10.1016/S0301-6226(00)00202-5.

Fabà L, Gasa J, Tokach MD, Varella E, Solà-Oriol D. Effects of supplementing organic microminerals and methionine during the rearing phase of replacement gilts on lameness, growth, and body composition. J Anim Sci. 2018;96(8):3274-87. http://doi.org/10.1093/jas/sky195. PMid:29767794.

Faccin JEG, Tokach MD, Goodband RD, DeRouchey JM, Woodworth JC, Gebhardt JT. Gilt development to improve offspring performance and survivability. J Anim Sci. 2022;100(6):1-10. http://doi.org/10.1093/jas/skac128. PMid:35708589.

Faggion S, Boschi E, Veroneze R, Carnier P, Bonfatti V. Genomic prediction and genome-wide association study for boar taint compounds. Animals. 2023;13(15):2450. http://doi.org/10.3390/ani13152450. PMid:37570259.

Freking BA, Lents CA, Vallet JL. Selection for uterine capacity improves lifetime productivity of sows. Anim Reprod Sci. 2016;167:16-21. http://doi.org/10.1016/j.anireprosci.2016.01.018. PMid:26869209.

Freking BA, Leymaster KA, Vallet JL, Christenson RK. Number of fetuses and conceptus growth throughout gestation in lines of pigs selected for ovulation rate or uterine capacity. J Anim Sci. 2007;85(9):2093-103. http://doi.org/10.2527/jas.2006-766. PMid:17504953.

Freyer G. Maximum number of total born piglets in a parity and individual ranges in litter size expressed as specific characteristics of sows. J Anim Sci Technol. 2018;60(1):13. http://doi.org/10.1186/s40781-018-0172-x.

Ganmaa D, Sato A. The possible role of female sex hormones in milk from pregnant cows in the development of breast, ovarian and corpus uteri cancers. Med Hypotheses. 2005;65(6):1028-37. http://doi.org/10.1016/j.mehy.2005.06.026. PMid:16125328.

García-Gómez E, Vazquez-Martinez ER, Reyes-Mayoral C, Cruz-Orozco OP, Camacho-Arroyo I, Cerbon M. Regulation of inflammation pathways and inflammasome by sex steroid hormones in endometriosis. Front Endocrinol. 2020;10:935. http://doi.org/10.3389/fendo.2019.00935. PMid:32063886.

Gerritsen R, Soede NM, Hazeleger W, Langendijk P, Dieleman SJ, Taverne MAM, Kemp B. Intermittent suckling enables estrus and pregnancy during lactation in sows: effects of stage of lactation and lactation during early pregnancy. Theriogenology. 2009;71(3):432-40. http://doi.org/10.1016/j.theriogenology.2008.08.011. PMid:18789517.

Goudet G, Nadal-Desbarats L, Douet C, Savoie J, Staub C, Venturi E, Ferchaud S, Boulot S, Prunier A. Salivary and urinary metabolome analysis for pre-puberty-related biomarkers identification in porcine. Animal. 2019;13(4):760-70. http://doi.org/10.1017/S1751731118002161. PMid:30182861.

Goudet G, Prunier A, Nadal-Desbarats L, Grivault D, Ferchaud S, Pianos A, Haddad L, Montigny F, Douet C, Savoie J, Maupertuis F, Roinsard A, Boulot S, Liere P. Steroidome and metabolome analysis in gilt saliva to identify potential biomarkers of boar effect receptivity. Animal. 2021;15(2):100095. http://doi.org/10.1016/j.animal.2020.100095. PMid:33573980.

Graves KL, Mordhorst BM, Wright EC, Hale BJ, Stalder KJ, Keating AF, Ross JW. Identification of measures predictive of age of puberty onset in gilts. Transl Anim Sci. 2019;4(1):285-92. http://doi.org/10.1093/tas/txz173. PMid:32704987.

Gregoraszczuk EŁ, Ptak A, Wojciechowicz T, Nowak K. Action of IGF-I on expression of the long form of the leptin receptor (ObRb) in the prepubertal period and throughout the estrous cycle in the mature pig ovary. J Reprod Dev. 2007;53(2):289-95. http://doi.org/10.1262/jrd.18071. PMid:17139134.

Gruhot TR, Calderón Díaz JA, Baas TJ, Stalder KJ. Using first and second parity number born alive information to estimate later reproductive performance in sows. Livest Sci. 2017;196:22-7. http://doi.org/10.1016/j.livsci.2016.12.009.

Guthrie HD, Polge C. Treatment of pregnant gilts with a prostaglandin analogue, Cloprostenol, to control oestrus and fertility. J Reprod Fertil. 1978;52(2):271-3. http://doi.org/10.1530/jrf.0.0520271. PMid:633213.

Hernandez-Medrano JH, Williams RW, van Drunen Littel-van den Hurk S, Peters AR, Hannant D, Campbell BK, Webb R. Early postnatal immunisation against gonadotrophin-releasing hormone induces a high but differential immune response in heifer calves. Res Vet Sci. 2013;95(2):472-9. http://doi.org/10.1016/j.rvsc.2013.05.014. PMid:23778305.

Holyoake PK, Dial GD, Trigg T, King VL. Reducing piglet mortality through supervision during the perinatal period. J Anim Sci. 1995;73(12):3543-51. http://doi.org/10.2527/1995.73123543x. PMid:8655427.

Hoving LL, Soede NM, Graat EAM, Feitsma H, Kemp B. Effect of live weight development and reproduction in first parity on reproductive performance of second parity sows. Anim Reprod Sci. 2010;122(1-2):82-9. http://doi.org/10.1016/j.anireprosci.2010.07.009. PMid:20727690.

Huirne RBM, Dijkhuizen AA, Renkema JA. Economic optimization of sow replacement decisions on the personal computer by method of stochastic dynamic programming. Livest Prod Sci. 1991;28(4):331-47. http://doi.org/10.1016/0301-6226(91)90014-H.

Iida R, Koketsu Y. Climatic factors associated with peripartum pig deaths during hot and humid or cold seasons. Prev Vet Med. 2014;115(3-4):166-72. http://doi.org/10.1016/j.prevetmed.2014.03.019. PMid:24785123.

Iida R, Koketsu Y. Number of pigs born alive in parity 1 sows associated with lifetime performance and removal hazard in high- or low-performing herds in Japan. Prev Vet Med. 2015;121(1-2):108-14. http://doi.org/10.1016/j.prevetmed.2015.06.012. PMid:26119515.

Iida R, Piñeiro C, Koketsu Y. Incidences and risk factors for prolapse removal in Spanish sow herds. Prev Vet Med. 2019;163:79-86. http://doi.org/10.1016/j.prevetmed.2018.12.016. PMid:30670190.

Iida R, Piñeiro C, Koketsu Y. Removal of sows in Spanish breeding herds due to lameness: Incidence, related factors and reproductive performance of removed sows. Prev Vet Med. 2020;179:105002. http://doi.org/10.1016/j.prevetmed.2020.105002. PMid:32388036.

Jarvis S, van der Vegt BJ, Lawrence AB, McLean KA, Deans LA, Chirnside J, Calvert SK. The effect of parity and environmental restriction on behavioural and physiological responses of pre-parturient pigs. Appl Anim Behav Sci. 2001;71(3):203-16. http://doi.org/10.1016/S0168-1591(00)00183-0. PMid:11230901.

Jørgensen B. Longevity of breeding sows in relation to leg weakness symptoms at six months of age. Acta Vet Scand. 2000;41(2):105-21. http://doi.org/10.1186/BF03549643. PMid:10965562.

Kaeoket K. Study on the oestrous synchronization in gilts by using progestin altrenogest and hCG: its effect on the follicular development, ovulation time and subsequent reproductive performance. Reprod Domest Anim. 2008;43(1):127-9. http://doi.org/10.1111/j.1439-0531.2007.00901.x. PMid:18069947.

Kashanian M, Dadkhah F, Mokhtari F. Effect of intramuscular administration of dexamethasone on the duration of labor. Int J Gynaecol Obstet. 2008;102(3):259-62. http://doi.org/10.1016/j.ijgo.2008.04.009. PMid:18534594.

Kemp B, Silva CLA, Soede NM. Recent advances in pig reproduction: focus on impact of genetic selection for female fertility. Reprod Domest Anim. 2018;53(Suppl 2):28-36. http://doi.org/10.1111/rda.13264. PMid:30238653.

Kemp B, Soede NM. Relationship of weaning-to-estrus interval to timing of ovulation and fertilization in sows. J Anim Sci. 1996;74(5):944-9. http://doi.org/10.2527/1996.745944x. PMid:8726724.

Kiefer ZE, Koester LR, Showman L, Studer JM, Chipman AL, Keating AF, Schmitz-Esser S, Ross JW. Vaginal microbiome and serum metabolite differences in late gestation commercial sows at risk for pelvic organ prolapse. Sci Rep. 2021a;11(1):6189. http://doi.org/10.1038/s41598-021-85367-3. PMid:33731737.

Kiefer ZE, Studer JM, Chipman AL, Adur MK, Mainquist-Whigham C, Gabler NK, Keating AF, Ross JW. Circulating biomarkers associated with pelvic organ prolapse risk in late gestation sows. J Anim Sci. 2021b;99(8):1-8. http://doi.org/10.1093/jas/skab207. PMid:34228800.

Kim JS, Jin DI, Lee JH, Son DS, Lee SH, Yi YJ, Park CS. Effects of teat number on litter size in gilts. Anim Reprod Sci. 2005;90(1-2):111-6. http://doi.org/10.1016/j.anireprosci.2005.01.013. PMid:15894439.

Kirkwood RN. Pharmacological intervention in swine reproduction. Swine Health Prod. 1999;7:29-35.

Knauer M, Stalder KJ, Serenius T, Baas TJ, Berger PJ, Karriker L, Goodwin RN, Johnson RK, Mabry JW, Miller RK, Robison OW, Tokach MD. Factors associated with sow stayability in 6 genotypes. J Anim Sci. 2010;88(11):3486-92. http://doi.org/10.2527/jas.2009-2319. PMid:20675607.

Knox RV, Arend LS, Buerkley AL, Patterson JL, Foxcroft GR. Effects of physical or fenceline boar exposure and exogenous gonadotropins on puberty induction and subsequent fertility in gilts. J Anim Sci. 2021;99(12):1-11. http://doi.org/10.1093/jas/skab348. PMid:34967902.

Knox RV. Follicle development in pigs: state of the art. Mol Reprod Dev. 2023;90(7):480-90. http://doi.org/10.1002/mrd.23576. PMid:35642618.

Koketsu Y, Dial GD. Factors influencing the postweaning reproductive performance of sows on commercial farms. Theriogenology. 1997;47(7):1445-61. http://doi.org/10.1016/S0093-691X(97)00135-0. PMid:16728090.

Koketsu Y, Iida R. Farm data analysis for lifetime performance components of sows and their predictors in breeding herds. Porcine Health Manag. 2020;6(1):24. http://doi.org/10.1186/s40813-020-00163-1. PMid:32963803.

Koketsu Y, Tani S, Iida R. Factors for improving reproductive performance of sows and herd productivity in commercial breeding herds. Porcine Health Manag. 2017;3(1):1-10. http://doi.org/10.1186/s40813-016-0049-7. PMid:28405457.

Koketsu Y, Iida R, Piñeiro C. Increased age at first-mating interacting with herd size or herd productivity decreases longevity and lifetime reproductive efficiency of sows in breeding herds. Porcine Health Manag. 2020;6:2. http://doi.org/10.1186/s40813-019-0142-9. PMid:32047646.

Kraeling RR, Webel SK. Current strategies for reproductive management of gilts and sows in North America. J Anim Sci Biotechnol. 2015;6(1):3. http://doi.org/10.1186/2049-1891-6-3. PMid:25838898.

Kranendonk G, Mulder EJH, Parvizi N, Taverne MAM. Prenatal stress in pigs: experimental approaches and field observations. Exp Clin Endocrinol Diabetes. 2008;116(7):413-22. http://doi.org/10.1055/s-2008-1065335. PMid:18484065.

Kristensen AR, Søllested TA. A sow replacement model using Bayesian updating in a three-level hierarchial Markov process II. Optimization model. Livest Prod Sci. 2004;87:25-36. http://doi.org/10.1016/j.livprodsci.2003.07.005.

Kummer R, Bernardi ML, Schenkel AC, Amaral WS Fa, Wentz I, Bortolozzo FP. Reproductive performance of gilts with similar age but with different growth rate at the onset of puberty stimulation. Reprod Domest Anim. 2009;44(2):255-9. http://doi.org/10.1111/j.1439-0531.2007.01050.x. PMid:18694424.

Langendijk P, van den Brand H, Soede NM, Kemp B. Effect of boar contact on follicular development and on estrus expression after weaning in primiparous sows. Theriogenology. 2000;54(8):1295-303. http://doi.org/10.1016/S0093-691X(00)00436-2. PMid:11192188.

Leal DF, Viana CHC, Almond GW, Monteiro MS, Garbossa CAP, Carnevale RF, Muro BBD, Poor AP, Pugliesi G, Nichi M, Watanabe TTN, Marques MG. Estrus synchronization of replacement gilts using estradiol cipionate and PGF and its effects on reproductive outcomes. Animals. 2022;12(23):3393. http://doi.org/10.3390/ani12233393. PMid:36496915.

Lents CA, Lindo NA, Hileman SM, Nonneman DJ. Physiological and genomic insight into neuroendocrine regulation of puberty in gilts. Domest Anim Endocrinol. 2020;73:106446. http://doi.org/10.1016/j.domaniend.2020.106446. PMid:32199704.

Lima RS, Martins T, Lemes KM, Binelli M, Madureira EH. Effect of a puberty induction protocol based on injectable long-acting progesterone on pregnancy success of beef heifers serviced by TAI. Theriogenology. 2020;154:128-34. http://doi.org/10.1016/j.theriogenology.2020.05.036. PMid:32603989.

Lucia T Jr, Corrêa MN, Deschamps JC, Peruzzo IA, Matheus JEM, Aleixo JAG. Influence of equine chorionic gonadotropin on weaning-to-estrus interval and estrus duration in early-weaned primiparous female swine. J Anim Sci. 1999a;77(12):3163-7. http://doi.org/10.2527/1999.77123163x. PMid:10641859.

Lucia T Jr, Dial GD, Marsh WE. Estimation of lifetime productivity of female swine. J Am Vet Med Assoc. 1999b;214(7):1056-9. http://doi.org/10.2460/javma.1999.214.07.1056. PMid:10200804.

Lucia T Jr, Dial GD, Marsh WE. Lifetime reproductive performance in female pigs having distinct reasons for removal. Livest Prod Sci. 2000a;63(3):213-22. http://doi.org/10.1016/S0301-6226(99)00142-6.

Lucia T Jr, Dial GD, Marsh WE. Lifetime reproductive and financial performance of female swine. J Am Vet Med Assoc. 2000b;216(11):1802-9. http://doi.org/10.2460/javma.2000.216.1802. PMid:10844975.

Lucia T Jr, Corrêa MN, Deschamps JC, Bianchi I, Donin MA, Machado AC, Meincke W, Matheus JEM. Risk factors for stillbirth in two swine farms in the South of Brazil. Prev Vet Med. 2002;53(4):285-92. http://doi.org/10.1016/S0167-5877(01)00288-4. PMid:11937235.

Lurette A, Belloc C, Touzeau S, Hoch T, Seegers H, Fourichon C. Modelling batch farrowing management within a farrow-to-finish pig herd: influence of management on contact structure and pig delivery to the slaughterhouse. Animal. 2008;2(1):105-16. http://doi.org/10.1017/S1751731107000997. PMid:22444969.

Magnabosco D, Bernardi ML, Wentz I, Cunha ECP, Bortolozzo FP. Low birth weight affects lifetime productive performance and longevity of female swine. Livest Sci. 2016;184:119-25. http://doi.org/10.1016/j.livsci.2015.12.008.

Mainau E, Manteca X. Pain and discomfort caused by parturition in cows and sows. Appl Anim Behav Sci. 2011;135(3):241-51. http://doi.org/10.1016/j.applanim.2011.10.020.

Mills KM, Schinckel AP, Stevens JG, Casey TM, Stewart KR. Evaluation of on-farm indicators of gilt reproductive performance potential at 21 days of age. Transl Anim Sci. 2020;4(4):1-8. http://doi.org/10.1093/tas/txaa210. PMid:33409465.

Mills KM, Ferreira CR, Stevens JG, Stewart KR, Casey TM. Biomarkers predictive of long-term fertility found in vaginal lipidome of gilts at weaning. J Anim Sci. 2021;99(8):a210. http://doi.org/10.1093/jas/skab189. PMid:34110418.

Miranda VO, Oliveira FC, Dias JH, Vargas Júnior SF, Goularte KL, Sá OG Fo, Baldassarre H, Vieira AD, Lucia T Jr, Gasperin BG. Estrous resynchronization in ewes with unknown pregnancy status. Theriogenology. 2018;106:103-7. http://doi.org/10.1016/j.theriogenology.2017.10.019. PMid:29049921.

Monteiro MS, Matias DN, Poor AP, Dutra MC, Moreno LZ, Parra BM, Silva APSP, Matajira CEC, Gomes VTM, Barbosa MRF, Sato MIZ, Moreno AM. Causes of sow mortality and risks to post-mortem findings in a Brazilian intensive swine production system. Animals. 2022;12(14):1804. http://doi.org/10.3390/ani12141804. PMid:35883351.

Moreira F, Gheller SMM, Mondadori RG, Varela AS Jr, Corcini CD, Lucia T Jr. Presence of leptin and its receptor in the hypothalamus, uterus and ovaries of swine females culled with distinct ovarian statuses and parities. Reprod Domest Anim. 2014;49(6):1074-8. http://doi.org/10.1111/rda.12438. PMid:25363738.

Muro BBD, Carnevale RF, Leal DF, Torres MA, Mendonça MV, Nakasone DH, Martinez CHG, Ravagnani GM, Monteiro MS, Poor AP, Martins SMMK, Viau P, Oliveira CA, Pulz LH, Strefezzi RF, Almond GW, Andrade AFC. Supplemental progesterone during early pregnancy exerts divergent responses on embryonic characteristics in sows and gilts. Animal. 2020;14(6):1234-40. http://doi.org/10.1017/S1751731119002982. PMid:31907084.

Nagel C, Aurich C, Aurich J. Stress effects on the regulation of parturition in different domestic animal species. Anim Reprod Sci. 2019;207:153-61. http://doi.org/10.1016/j.anireprosci.2019.04.011. PMid:31054786.

Nissen AK, Soede NM, Hyttel P, Schmidt M, D’Hoore L. The influence of time of insemination relative to time of ovulation on farrowing frequency and litter size in sows, as investigated by ultrasonography. Theriogenology. 1997;47(8):1571-82. http://doi.org/10.1016/S0093-691X(97)00162-3. PMid:16728099.

Noguchi M, Yoshioka K, Suzuki C, Arai S, Itoh S, Wada Y. Estrus synchronization with pseudopregnant gilts induced by a single treatment of estradiol dipropionate. J Reprod Dev. 2010;56(4):421-7. http://doi.org/10.1262/jrd.10-006T. PMid:20484869.

Noguchi M, Yoshioka K, Suzuki C, Itoh S, Kaneko H. An efficient protocol for inducing pseudopregnancy using estradiol dipropionate and follicular development associated with changes in reproductive hormones after prostaglandin F2alpha treatment in pseudopregnant sows. Reprod Biol Endocrinol. 2011;9(1):157. http://doi.org/10.1186/1477-7827-9-157. PMid:22168485.

Nonneman D, Lents C, Rohrer G, Rempel L, Vallet J. Genome-wide association with delayed puberty in swine. Anim Genet. 2014;45(1):130-2. http://doi.org/10.1111/age.12087. PMid:23980905.

Ocepek M, Andersen-Ranberg I, Edwards SA, Fredriksen B, Framstad T, Andersen IL. Can a super sow be a robust sow? Consequences of litter investment in purebred and crossbred sows of different parities. J Anim Sci. 2016;94(8):3550-60. http://doi.org/10.2527/jas.2016-0386. PMid:27695774.

Oliviero C, Ollila A, Andersson M, Heinonen M, Voutila K, Serenius T, Peltoniemi O. Strategic use of anti-GnRH vaccine allowing selection of breeding boars without adverse effects on reproductive or production performances. Theriogenology. 2016;85(3):476-82. http://doi.org/10.1016/j.theriogenology.2015.09.027. PMid:26474682.

Otte MV, Moreira F, Bianchi I, Oliveira J Jr, Mendes RE, Haas CS, Anciuti NA, Rovani MT, Gasperin BG, Lucia T Jr. Effects of supplying omega-3 polyunsaturated fatty acids to gilts after weaning on metabolism and ovarian gene expression. J Anim Sci. 2019;97(1):374-84. http://doi.org/10.1093/jas/sky419. PMid:30371788.

Paiva RC, Moura CA, Thomas P, Haberl B, Greiner L, Rademacher CJ, Silva APSP, Trevisan G, Linhares DCL, Silva GS. Risk factors associated with sow mortality in breeding herds under one production system in the Midwestern United States. Prev Vet Med. 2023;213:105883. http://doi.org/10.1016/j.prevetmed.2023.105883. PMid:36867926.

Patterson JL, Beltranena E, Foxcroft G. The effect of gilt age at first estrus and breeding on third estrus on sow body weight changes and long-term reproductive performance. J Anim Sci. 2010;88(7):2500-13. http://doi.org/10.2527/jas.2008-1756. PMid:20228234.

Patterson JL, Foxcroft G. Gilt management for fertility and longevity. Animals. 2019;9(7):434. http://doi.org/10.3390/ani9070434. PMid:31324002.

Patterson JL, Bernardi ML, Allerson M, Hanson A, Holden N, Bruner L, Pinilla JC, Foxcroft G. Associations among individual gilt birth weight, litter birth weight phenotype, and the efficiency of replacement gilt production. J Anim Sci. 2020;98(11):1-13. http://doi.org/10.1093/jas/skaa331. PMid:33033834.

PigCHAMP® [Internet]. 2023 [cited 2023 Dec 2]. Available from: https://www.pigchamp.com

Poulsen Nautrup B, van Vlaenderen I, Mah CK. The effect of immunization against gonadotropin-releasing factor in market gilts: meta-analyses of parameters relevant for pig producers, pork packers and retailers/consumers. Res Vet Sci. 2020;131:159-72. http://doi.org/10.1016/j.rvsc.2020.04.012. PMid:32387811.

Prunier A, Heinonen M, Quesnel H. High physiological demands in intensively raised pigs: impact on health and welfare. Animal. 2010;4(6):886-98. http://doi.org/10.1017/S175173111000008X. PMid:22444261.

Qin LQ, Wang PY, Kaneko T, Hoshi K, Sato A. Estrogen: one of the risk factors in milk for prostate cancer. Med Hypotheses. 2004;62(1):133-42. http://doi.org/10.1016/S0306-9877(03)00295-0. PMid:14729019.

Quirino M, Ulguim RR, Bernardi ML, Pereira VN, Magoga J, Gianluppi RDF, Mellagi APG, Gasperin BG, Bortolozzo FP. Follicular dynamic and reproductive performance of gilts submitted to estrous cycle synchronization using two different progestogen sources. Theriogenology. 2020;158:31-8. http://doi.org/10.1016/j.theriogenology.2020.08.035. PMid:32927198.

Ravagnani GM, Martinez CHG, Carnevale RF, Muro BBD, Mendonça MV, Pavaneli APP, Passareli MS, Nakasone DH, Strefezzi RF, Martins SMMK, Andrade AFC. Effects of oestrous synchronization with altrenogest in gilts on endometrial and embryonic characteristics. Animal. 2020;14(9):1899-905. http://doi.org/10.1017/S1751731120000658. PMid:32290879.

Rensis F, Saleri R, Tummaruk P, Techakumphu M, Kirkwood RN. Prostaglandin F2α and control of reproduction in female swine: a review. Theriogenology. 2012;77(1):1-11. http://doi.org/10.1016/j.theriogenology.2011.07.035. PMid:21958632.

Rodriguez-Zas SL, Southey BR, Knox RV, Connor JF, Lowe JF, Roskamp BJ. Bioeconomic evaluation of sow longevity and profitability. J Anim Sci. 2003;81(12):2915-22. http://doi.org/10.2527/2003.81122915x. PMid:14677846.

Romoser MR, Hale BJ, Seibert JT, Gall T, Rademacher CJ, Stalder KJ, Baumgard LH, Keating AF, Ross JW. Methods for reproductive tract scoring as a tool for improving sow productivity. Transl Anim Sci. 2019;4(1):275-84. http://doi.org/10.1093/tas/txz160. PMid:32704986.

Rutherford KMD, Donald RD, Arnott G, Rooke JA, Dixon L, Mehers JJM, Turnbull J, Lawrence AB. Farm animal welfare: assessing risks attributable to the prenatal environment. Anim Welf. 2012;21(3):419-29. http://doi.org/10.7120/09627286.21.3.419.

Saito H, Sasaki Y, Koketsu Y. Associations between age of gilts at first mating and lifetime performance or culling risk in commercial herds. J Vet Med Sci. 2011;73(5):555-9. http://doi.org/10.1292/jvms.10-0040. PMid:21173552.

Sankarganesh D, Kirkwood RN, Angayarkanni J, Achiraman S, Archunan G. Pig pheromones and behaviors: a review. Theriogenology. 2021;175:1-6. http://doi.org/10.1016/j.theriogenology.2021.08.032. PMid:34481226.

Sasaki Y, Koketsu Y. Mortality, death interval, survivals, and herd risk factors for female pigs in commercial breeding herds. J Anim Sci. 2008;86(11):3159-65. http://doi.org/10.2527/jas.2008-1047. PMid:18567721.

Sasaki Y, Saito H, Shimomura A, Koketsu Y. Consecutive reproductive performance after parity 2 and lifetime performance in sows that had reduced pigs born alive from parity 1 to 2 in Japanese commercial herds. Livest Sci. 2011;139(3):252-7. http://doi.org/10.1016/j.livsci.2011.01.017.

Schenkel AC, Bernardi ML, Bortolozzo FP, Wentz I. Body reserve mobilization during lactation in first parity sows and its effect on second litter size. Livest Sci. 2010;132(1-3):165-72. http://doi.org/10.1016/j.livsci.2010.06.002.

Schütz J, Rudolph J, Steiner A, Rothenanger E, Hüsler J, Hirsbrunner G. Immunization against gonadotropin-releasing hormone in female beef calves to avoid pregnancy at time of slaughter. Animals. 2021;11(7):2071. http://doi.org/10.3390/ani11072071. PMid:34359199.

See GM, Gruhot TR, Spangler MK, Lewis RM. Longitudinal analysis of weight showed little relationship with age at puberty in gilts. J Anim Sci. 2018;96(12):4959-66. http://doi.org/10.1093/jas/sky366. PMid:30219873.

Sell-Kubiak E, Knol EF, Mulder HA, Pszczola M. Unraveling the actual background of second litter syndrome in pigs: based on Large White data. Animal. 2021;15(2):100033. http://doi.org/10.1016/j.animal.2020.100033. PMid:33573982.

Serenius T, Stalder KJ. Selection for sow longevity. J Anim Sci. 2006;84(Suppl):E166-71. http://doi.org/10.2527/2006.8413_supplE166x. PMid:16582089.

Silambarasan V, Deepalakshmi G, Sankarganesh D, Nithya V, Archunan G. Identification of potential pheromone source in sows. Behav Processes. 2019;168:103940. http://doi.org/10.1016/j.beproc.2019.103940. PMid:31446194.

Soede NM, Raaphorst CJ, Bouwman EG, Kirkwood RN. Effects of injection of hCG during the estrous cycle on follicle development and the inter-estrous interval. Theriogenology. 2001;55(4):901-9. http://doi.org/10.1016/S0093-691X(01)00452-6. PMid:11291913.

Soede NM, Langendijk P, Kemp B. Reproductive cycles in pigs. Anim Reprod Sci. 2011;124(3-4):251-8. http://doi.org/10.1016/j.anireprosci.2011.02.025. PMid:21397415.

Squires EJ, Bone C, Cameron J. Pork production with entire males: directions for control of boar taint. Animals. 2020;10(9):1665. http://doi.org/10.3390/ani10091665. PMid:32947846.

Stančić IB, Bošnjak DV, Radović IB, Stančić BL, Harvey RB, Anderson RC. Ovarian reaction and estrus manifestation in delayed puberty gilts after treatment with equine chorionic gonadotropin. Reprod Biol Endocrinol. 2012;10(1):61. http://doi.org/10.1186/1477-7827-10-61. PMid:22913331.

Steel A, Athorn RZ, Grupen CG. Anti-Müllerian hormone and oestradiol as markers of future reproductive success in juvenile gilts. Anim Reprod Sci. 2018;195:197-206. http://doi.org/10.1016/j.anireprosci.2018.05.024. PMid:29859701.

Supakorn C, Stock JD, Hostetler C, Stalder KJ. Prolapse incidence in swine breeding herds is a cause for concern. Open J Vet Med. 2017;7:85-97. http://doi.org/10.4236/OJVM.2017.78009.

Szymanska M, Blitek A. In vivo response of the corpus luteum to progesterone treatment of gilts during early gestation. Anim Reprod Sci. 2020;221:106583. http://doi.org/10.1016/j.anireprosci.2020.106583. PMid:32882581.

Takanashi A, McTaggart I, Koketsu Y. Swine herds achieve high performance by culling low lifetime efficiency sows in early parity. J Vet Med Sci. 2011;73(11):1405-9. http://doi.org/10.1292/jvms.10-0549. PMid:21712643.

Tani S, Piñeiro C, Koketsu Y. Recurrence patterns and factors associated with regular, irregular and late returns-to-service of female pigs and their lifetime. J Anim Sci. 2016;94:1924-32. http://doi.org/10.2527/jas.2016-0302. PMid:27285690.

Thingnes SL, Hallenstvedt E, Sandberg E, Framstad T. The effect of different dietary energy levels during rearing and mid-gestation on gilt performance and culling rate. Livest Sci. 2015;172:33-42. http://doi.org/10.1016/j.livsci.2014.11.012.

Torres-Rovira L, Gonzalez-Bulnes A, Succu S, Spezzigu A, Manca ME, Leoni GG, Sanna M, Pirino S, Gallus M, Naitana S, Berlinguer F. Predictive value of antral follicle count and anti-Müllerian hormone for follicle and oocyte developmental competence during the early prepubertal period in a sheep model. Reprod Fertil Dev. 2014;26(8):1094-106. http://doi.org/10.1071/RD13190. PMid:24008140.

Tummaruk P, Tantasuparuk W, Techakumphu M, Kunavongkrit A. Age, body weight and backfat thickness at first observed oestrus in crossbred Landrace × Yorkshire gilts, seasonal variations and their influence on subsequence reproductive performance. Anim Reprod Sci. 2007;99(1-2):167-81. http://doi.org/10.1016/j.anireprosci.2006.05.004. PMid:16765000.

Ulguim RR, Bianchi I, Lucia T Jr. Female lifetime productivity in a swine integration system using segregated gilt development units. Trop Anim Health Prod. 2014;46(4):697-700. http://doi.org/10.1007/s11250-014-0546-0. PMid:24497142.

Ulguim RD, Mallmann AL, Gasperin BG, Bernardi ML, Wentz I, Mellagi APG, Bortolozzo FP. Effects of intravaginal devices containing different dosages of medroxyprogesterone acetate for the control of the estrous cycle in gilts. Anim Reprod Sci. 2019;210:106200. http://doi.org/10.1016/j.anireprosci.2019.106200. PMid:31635772.

Ungerfeld R, Freitas-de-Melo A. Administration of a single dose of long-acting injectable progesterone formulation reduces the stress response to weaning in anestrous ewes. Domest Anim Endocrinol. 2023;82:106753. http://doi.org/10.1016/j.domaniend.2022.106753. PMid:36027631.

Vallet JL, Calderón-Díaz JA, Stalder KJ, Phillips C, Cushman RA, Miles JR, Rempel LA, Rohrer GA, Lents CA, Freking BA, Nonneman DJ. Litter-of-origin trait effects on gilt development. J Anim Sci. 2016;94(1):96-105. http://doi.org/10.2527/jas.2015-9644. PMid:26812316.

Vallet JL, Miles JR. The effect of farrowing induction on colostrum and piglet serum immunocrits is dependent on parity. J Anim Sci. 2017;95(2):688-96. http://doi.org/10.2527/jas2016.0993. PMid:28380602.

van den Brand H, Dieleman SJ, Soede NM, Kemp B. Dietary energy source at two feeding levels during lactation of primiparous sows: I. Effects on glucose, insulin, and luteinizing hormone and on follicle development, weaning-to-estrus interval, and ovulation rate. J Anim Sci. 2000;78(2):396-404. http://doi.org/10.2527/2000.782396x. PMid:10709931.

van Rens BT, van der Lende T. Parturition in gilts: duration of farrowing, birth intervals and placenta expulsion in relation to maternal, piglet and placental traits. Theriogenology. 2004;62(1-2):331-52. http://doi.org/10.1016/j.theriogenology.2003.10.008. PMid:15159125.

Vanderhaeghe C, Dewulf J, de Kruif A, Maes D. Non-infectious factors associated with stillbirth in pigs: a review. Anim Reprod Sci. 2013;139(1-4):76-88. http://doi.org/10.1016/j.anireprosci.2013.03.007. PMid:23602009.

Vargas AJ, Bernardi ML, Wentz I, Borchardt G No, Bortolozzo FP. Time of ovulation and reproductive performance over three parities after treatment of primiparous sows with PG600. Theriogenology. 2006;66(8):2017-23. http://doi.org/10.1016/j.theriogenology.2006.04.045. PMid:16870243.

Verdon M, Hansen CF, Rault J-L, Jongman E, Hansen LU, Plush K, Hemsworth PH. Effects of group housing on sow welfare: a review. J Anim Sci. 2015;93(5):1999-2017. http://doi.org/10.2527/jas.2014-8742. PMid:26020296.

Viana JHM, Pereira NES, Faria OAC, Dias LRO, Oliveira ER, Fernandes CAC, Siqueira LGB. Active immunization against GnRH as an alternative therapeutic approach for the management of Bos indicus oocyte donors diagnosed with chronic cystic ovarian disease. Theriogenology. 2021;172:133-41. http://doi.org/10.1016/j.theriogenology.2021.06.014. PMid:34166988.

Waclawik A, Kaczmarek MM, Blitek A, Kaczynski P, Ziecik AJ. Embryo-maternal dialogue during pregnancy establishment and implantation in the pig. Mol Reprod Dev. 2017;84(9):842-55. http://doi.org/10.1002/mrd.22835. PMid:28628266.

Wang C, Wu Y, Shu D, Wei H, Zhou Y, Peng K. An analysis of culling patterns during the breeding cycle and lifetime production from the aspect of culling reasons for gilts and sows in southwest China. Animals. 2019;9(4):160. http://doi.org/10.3390/ani9040160. PMid:31013730.

Wang Z, Liu BS, Wang XY, Wei QH, Tian H, Wang LQ. Effects of altrenogest on reproductive performance of gilts and sows: a meta-analysis. Anim Reprod Sci. 2018;197:10-21. http://doi.org/10.1016/j.anireprosci.2018.08.035. PMid:30197055.

Ward SA, Kirkwood RN, Song Y, Garg S, Plush KJ. Effect of dexamethasone and route of administration on sow farrowing behaviours, piglet delivery and litter performance. Animals. 2022;12(7):847. http://doi.org/10.3390/ani12070847. PMid:35405838.

Ward SA, Kirkwood RN, Plush KJ. Are larger litters a concern for piglet survival or an effectively manageable trait? Animals. 2020;10(2):309. http://doi.org/10.3390/ani10020309. PMid:32079160.

Werlang R, Argenti L, Fries H, Bernardi M, Wentz I, Bortolozzo F. Effects of breeding at the second oestrus or after post-weaning hormonal treatment with altrenogest on subsequent reproductive performance of primiparous sows. Reprod Domest Anim. 2011;46(5):818-23. http://doi.org/10.1111/j.1439-0531.2010.01747.x. PMid:21323753.

Wijesena HR, Nonneman DJ, Rohrer GA, Lents CA. Relationships of genomic estimated breeding values for age at puberty, birth weight, and growth during development in normal cyclic and acyclic gilts. J Anim Sci. 2023;101:1-12. http://doi.org/10.1093/jas/skad258. PMid:37565572.

Wijesiriwardana UA, Craig JR, Cottrell JJ, Dunshea FR, Pluske JR. Factors affecting the early growth and development of gilt progeny compared to sow progeny. Animal. 2022;16(8):100596. http://doi.org/10.1016/j.animal.2022.100596. PMid:35952479.

Will KJ, Magoga J, de Conti ER, Ulguim RR, Mellagi APG, Bortolozzo FP. Relationship between dexamethasone treatment around parturition of primiparous sows and farrowing performance and newborn piglet traits. Theriogenology. 2023;198:256-63. http://doi.org/10.1016/j.theriogenology.2022.12.044. PMid:36623428.

Wülbers-Mindermann M, Berg C, Illmann G, Baulain U, Algers B. The effect of farrowing environment and previous experience on the maternal behaviour of sows in indoor pens and outdoor huts. Animal. 2015;9(4):669-76. http://doi.org/10.1017/S1751731114003036. PMid:25496661.

Yang C, Li Y, Pan H-Y, Li M-Y, Pan J-M, Chen S-T, Zhang H-Y, Yang Z-S, Dou H-T, Yang Z-M. Female reproductive abnormalities in mouse adolescent pregnancy. Reproduction. 2021;162(5):353-65. http://doi.org/10.1530/REP-21-0240. PMid:34486978.

Zak L, Foxcroft GR, Aherne FX, Kirkwood RN. Role of luteinizing hormone in primiparous sow responses to split weaning. Reprod Domest Anim. 2008;43(4):445-50. http://doi.org/10.1111/j.1439-0531.2007.00932.x. PMid:18179631.

Zavy MT, Geisert RD, Buchanan DS, Norton SA. Estrogen-induced pseudopregnancy in gilts: its use in estrus synchronization and subsequent influence on litter response. Theriogenology. 1988;30(4):721-32. http://doi.org/10.1016/0093-691X(88)90307-X. PMid:16726514.

Ziecik AJ, Drzewiecka K, Gromadzka-Hliwa K, Klos J, Witek P, Knapczyk-Stwora K, Gajewski Z, Kaczmarek MM. Altrenogest affects the development and endocrine milieu of ovarian follicles in prepubertal and mature gilts. Biol Reprod. 2020;103(5):1069-84. http://doi.org/10.1093/biolre/ioaa136. PMid:32744329.

Ziecik AJ, Przygrodzka E, Jalali BM, Kaczmarek MM. Regulation of the porcine corpus luteum during pregnancy. Reproduction. 2018;156(3):R57-67. http://doi.org/10.1530/REP-17-0662. PMid:29794023.
 


Submitted date:
06/26/2024

Accepted date:
08/08/2024

66ffe665a953956e104097f3 animreprod Articles
Links & Downloads

Anim Reprod

Share this page
Page Sections