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Size and position of the reproductive tract impacts fertility outcomes and pregnancy losses in lactating dairy cows.
Madureira, A M L; Poole, R K; Burnett, T A; Guida, T G; Edwards, J L; Schrick, F N; Vasconcelos, J L M; Cerri, R L A; Pohler, K G.
Afiliación
  • Madureira AML; Applied Animal Biology, Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
  • Poole RK; Department of Animal Science, Pregnancy and Developmental Programming Area of Excellence, Texas A&M University, College Station, TX, 77843, USA.
  • Burnett TA; Applied Animal Biology, Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
  • Guida TG; Department of Animal Production, São Paulo State University, Botucatu, 18168-000, Brazil.
  • Edwards JL; Department of Animal Science, University of Tennessee, Knoxville, TN, 37996, USA.
  • Schrick FN; Department of Animal Science, University of Tennessee, Knoxville, TN, 37996, USA.
  • Vasconcelos JLM; Department of Animal Production, São Paulo State University, Botucatu, 18168-000, Brazil.
  • Cerri RLA; Applied Animal Biology, Faculty of Land and Food Systems, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada.
  • Pohler KG; Department of Animal Science, Pregnancy and Developmental Programming Area of Excellence, Texas A&M University, College Station, TX, 77843, USA. Electronic address: kpohler@tamu.edu.
Theriogenology ; 158: 66-74, 2020 Dec.
Article en En | MEDLINE | ID: mdl-32932186
There are multiple factors that contribute to reduced fertility in lactating dairy cows. Recently, a reproductive tract size and position score (SPS) system was developed as a management tool to identify dairy cows with decreased fertility. The aim of this study was to evaluate the association between the SPS on fertility outcomes such as ovulation failure, pregnancy per artificial insemination (P/AI), concentration of pregnancy-associated glycoproteins (PAGs), and pregnancy loss in lactating dairy cows. Primiparous and multiparous lactating Holstein cows (n = 869) were enrolled at two locations. Location 1 (Loc. 1) in Minas Gerais, Brazil (n = 613) and location 2 (Loc. 2) in Agassiz, British Columbia, Canada (n = 256). At the time of AI (d 0), cows were classified as SPS (small [SPS1], medium [SPS2], or large [SPS3] sized reproductive tract) and ovulation failure was determined at 48 h and 7 d post-AI via ultrasonography (Loc. 2 only). Blood samples were collected on d 24 and 31 of gestation for quantification of PAGs and pregnancy diagnosis was performed via ultrasonography at d 31 and 60 post-AI (Loc. 1) and at d 31 ± 3 and 60 ± 3 post-AI (Loc. 2). Cows diagnosed pregnant at d 31 post-AI but not pregnant at d 60 were defined to have undergone late embryonic pregnancy loss. Parity was found to impact SPS (P < 0.01), as primiparous cows had a higher frequency of SPS1 and lower frequency of SPS3 when compared with multiparous cows (SPS1: 42.6 vs. 15.0%; SPS3: 7.0 vs. 22.0%, respectively). Cows classified as SPS3 had greater ovulation failure at 48 h (P = 0.04) and 7 d post-AI (P = 0.05). Cows classified as SPS1 had greater P/AI when compared to SPS2 and SPS3 (45.9 ± 3.3 vs. 37.4 ± 2.6 and 29.1 ± 3.5%, respectively; P = 0.004). There was no interaction between parity and SPS on P/AI. Pregnancy loss between 31 and 60 d post-AI was increased in cows classified as SPS3 compared to SPS2 and SPS1 (24.3 ± 0.05 vs. 11.6 ± 0.02 and 9.4 ± 0.02%, respectively; P = 0.04). Cows classified as SPS1 and SPS2 had greater concentrations of PAGs at 31 d post-AI when compared to SPS3 at both Loc.1 (P < 0.01) and Loc. 2 (P < 0.01). There was no interaction between SPS and pregnancy loss on PAGs at 24 and 31 d post- AI for either Loc. 1 (P = 0.75 and P = 0.76, respectively) or Loc. 2 (P = 0.61 and P = 0.81, respectively). In conclusion, cows that were classified as SPS3 had greater ovulation failure, reduced P/AI, similar concentrations of PAG on d 24, but decreased on d 31, and a greater incidence of pregnancy loss. Thus, size and position of the reproductive tract is associated with fertility and this scoring system could be used to make reproductive management decisions on dairy operations.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Enfermedades de los Bovinos / Sincronización del Estro Tipo de estudio: Prognostic_studies Límite: Animals / Pregnancy País/Región como asunto: America do sul / Brasil Idioma: En Revista: Theriogenology Año: 2020 Tipo del documento: Article País de afiliación: Canadá Pais de publicación: Estados Unidos

Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Enfermedades de los Bovinos / Sincronización del Estro Tipo de estudio: Prognostic_studies Límite: Animals / Pregnancy País/Región como asunto: America do sul / Brasil Idioma: En Revista: Theriogenology Año: 2020 Tipo del documento: Article País de afiliación: Canadá Pais de publicación: Estados Unidos