{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,16]],"date-time":"2025-12-16T14:41:23Z","timestamp":1765896083143,"version":"3.48.0"},"reference-count":7,"publisher":"Polish Academy of Sciences Chancellery","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"abstract":"<jats:p>The aim of the study was to evaluate changes in fertility outcomes in dairy cow herds in north-eastern Poland over a 20-year period. Data from the 2003\u20132004 and 2023\u20132024 calving seasons were compared, including herd size, milk yield, conception rate, number of services per conception, inter-calving period, and culling rate due to infertility. Over the study period, average milk yield increased substantially, while fertility parameters deteriorated significantly. First-service conception rate declined, the number of services per conception increased, inter-calving periods became longer, and culling due to infertility rose markedly. All differences between periods were statistically significant (p\u22640.05). The results indicate a negative association between increased milk yield and fertility outcomes in dairy cows over the past two decades.<\/jats:p>","DOI":"10.24425\/pjvs.2025.157282","type":"journal-article","created":{"date-parts":[[2025,12,16]],"date-time":"2025-12-16T14:19:30Z","timestamp":1765894770000},"page":"673-673","source":"Crossref","is-referenced-by-count":0,"title":["Trend in fertility outcomes of dairy cows in north-eastern Poland over the past 20 years"],"prefix":"10.24425","author":[{"given":"W.","family":"Bara\u0144ski","sequence":"first","affiliation":[{"name":"Department of Animal Reproduction with Clinic, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, Oczapowskiego 14, 10-719 Olsztyn, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"S.","family":"Zdu\u0144czyk","sequence":"additional","affiliation":[{"name":"Department of Animal Reproduction with Clinic, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, Oczapowskiego 14, 10-719 Olsztyn, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"M.","family":"Zieli\u0144ska","sequence":"additional","affiliation":[{"name":"Department of Animal Reproduction with Clinic, Faculty of Veterinary Medicine, University of Warmia and Mazury in Olsztyn, Oczapowskiego 14, 10-719 Olsztyn, Poland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"M.","family":"Rudowska","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"37468","published-online":{"date-parts":[[2025,12,12]]},"reference":[{"key":"#cr-split#-ref0.1","unstructured":"Bara\u0144ski W, Zdu\u0144czyk S, Janowski T, De Kruif A, Opsomer G, Dewulf J (2005) Dairy herd health-care program. [in Polish], Med. Weter 61: 14-18. Bogucki M, Sawa A, Neja W (2007) Differences in fertility parameters of dairy cows due to increasing lactation yield. Acta Sci Pol Zootechnica 6: 3-10. Borkowska D, Pi\u0105tek D, Janu\u015b E, Mucha J (2012) Fertility indices of cows in a high-yielding herd. Rocz Nauk PTZ 8: 21-29.&nbsp"},{"key":"#cr-split#-ref0.2","doi-asserted-by":"crossref","unstructured":"Butler WR (1998) Review: effect of protein nutrition on ovarian and uterine physiology in dairy cattle. J Dairy Sci 81: 2533-2539. Crowe MA, Histens M, Opsomer G (2018) Reproductive management in dairy cows - the future. Ir Vet J 71: 1.&nbsp","DOI":"10.3168\/jds.S0022-0302(98)70146-8"},{"key":"#cr-split#-ref0.3","doi-asserted-by":"crossref","unstructured":"De Kruif A, Leroy J, Opsomer G (2008) Reproductive performance in high producing dairy cows: practical implications. Tier\u00e4rztl Prax 36 (Suppl 1): S29-S33. Dobson H, Smith R, Royal M, Knight C, Sheldon I (2007) The high-producing dairy cow and its reproductive performance. Reprod Domest Anim 42 (Suppl 2): 17-23.&nbsp","DOI":"10.1111\/j.1439-0531.2007.00906.x"},{"key":"#cr-split#-ref0.4","unstructured":"Grummer RR (2007) Strategies to improve fertility of high yielding dairy farms: management of the dry period. Theriogenology 68 (Suppl 1): S281-S288. Jayawardana JM, Lopez-Villalobos N, McNaughton LR, Hickson RE (2023) Heritabilities and genetic and phenotypic correlations for milk production and fertility traits of spring-calved once-daily or twice-daily milking cows in New Zealand. J Dairy Sci 106: 1910-1924 Janu\u015b E, Borkowska D (2006) Selected indices of fertility of cows of different milk production. [in Polish], Ann Univ Mariae Curie-Sk\u0142odowska,&nbsp;sec. EE, 24: 33-37. Krzy\u017cewski J, Strza\u0142kowska N, Reklewski Z, Dymnicki E, Ryniewicz Z (2004) Influence of calving interval length in HF cows on milk yield, its composition and some reproduction traits. Med Weter 60: 76-79. LeBlanc SJ (2013) Is a high level of milk production compatible with good reproductive performance in dairy cows? Anim Front 3: 84-91. Lucy MC (2001) Reproductive loss in high-producing dairy cattle: where will it end? J Dairy Sci 84: 1277-1293.&nbsp"},{"key":"#cr-split#-ref0.5","doi-asserted-by":"crossref","unstructured":"Mee JF (2004) Temporal trends in reproductive performance in Irish dairy herds and associated risk factors. Ir Vet J 57: 58-166.&nbsp","DOI":"10.1186\/2046-0481-57-3-158"},{"key":"#cr-split#-ref0.6","unstructured":"Neja W, Jankowska M, Sawa A, Bogucki M (2013) Analysis of milk and reproductive performance of the active population of cows in Poland. J Cent Eur Agr 14: 91-101. Polish Federation of Cattle Breeders and Dairy Farmers (2024). Evaluation and breeding of dairy cattle. 2023 Data [in Polish]. PFHBiPM, Warsaw, https:\/\/pfhb.pl\/publikacje Roche JF (2006) The effect of nutritional management of the dairy cow on reproductive efficiency. Anim Reprod Sci 96: 282-296. Sawa A, Bogucki M (2010) Effect of extended lactations of primiparas on their lifetime production efficiency. [in Polish], Rocz Nauk PTZ 6: 165-173.&nbsp"},{"key":"#cr-split#-ref0.7","unstructured":"Siatka K, Sawa, A, Piwczy\u0144ski D, Bogucki, M, Krezel-Czopek S (2018) Factors affecting first insemination success in Polish Holstein-Friesian cows. Anim Sci Pap Rep 36: 275-285. Statistical Yearbook of the Republic of Poland. [in Polish] (2004), GUS, Warsaw, https:\/\/stat.gov.pl\/obszary-tematyczne\/ &nbsp;roczniki-statystyczne\/roczniki-statystyczne\/rocznikstatystyczny-rzeczypospolitej-polskiej-2004,2,12.html Statistical Yearbook of the Republic of Poland. [in Polish] (2024), GUS, Warsaw, https:\/\/stat.gov.pl\/obszary-tematyczne\/ &nbsp;roczniki-statystyczne\/roczniki-statystyczne\/rocznikstatystyczny-rzeczypospolitej-polskiej-2024,2,24.html Tiezzi F, Maltecca C, Cecchinato A, Penasa M, Bittante G (2012) Genetic parameters for fertility of dairy heifers and cows at different parities and relationships with production traits in first lactation. J Dairy Sci 95: 7355-7362. Walsh SW, Williams EJ, Evans AC (2011) A review of the causes of poor fertility in high milk producing dairy cows. Anim Reprod Sci 123: 127-138. Wiltbank M, Lopez H, Sartori R, Sangsritavong S, G\u00fcmen A (2006) Changes in reproductive physiology of lactating dairy cows due to elevated steroid metabolism. Theriogenology 65: 17-29."}],"container-title":["Polish Journal of Veterinary Sciences"],"original-title":[],"language":"pl","link":[{"URL":"https:\/\/journals.pan.pl\/Content\/137627\/PDF\/18%20_%20Baranski%20_%20Short.pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,12,16]],"date-time":"2025-12-16T14:28:23Z","timestamp":1765895303000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.pan.pl\/dlibra\/publication\/157282\/edition\/137627\/content"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,12,12]]},"references-count":7,"URL":"https:\/\/doi.org\/10.24425\/pjvs.2025.157282","relation":{},"ISSN":["1505-1773"],"issn-type":[{"type":"print","value":"1505-1773"}],"subject":[],"published":{"date-parts":[[2025,12,12]]}}}