Influence of seasonality, timing of insemination and rectal temperature on conception rate of crossbred dairy cows

Authors

  • Fransérgio Rocha de Souza Universidade Federal de Uberlândia
  • Carla Cristian Campos Universidade Federal de Uberlândia
  • Natascha Almeida Marques da Silva Universidade Federal de Uberlândia UFU
  • Ricarda Maria dos Santos Universidade Federal de Uberlândia

DOI:

https://doi.org/10.5433/1679-0359.2016v37n1p155

Keywords:

Reproduction efficiency, Heat stress, Artificial insemination, Crossbred cows.

Abstract

This study aimed to evaluate the effects of rectal temperature (RT) on conception rate (CR), as well as the effects of seasonality (spring-summer vs. autumn-winter) and timing of artificial insemination (AI) (morning vs. afternoon) on RT and CR in crossbred dairy cows (Holstein x Gyr). The experiment was conducted on a dairy farm in Centralina, MG, where 1,219 conventional and fixed-time inseminations were analyzed. The RT was measured immediately before AI using a digital thermometer. Pregnancy diagnosis was performed using ultrasonography between 28 and 60 days after AI. T The effects of seasonality and timing of AI on RT were analyzed with a Mann-Whitney U test and the effects of RT (above or below the average), seasonality and timing of AI on CR were analyzed with a Chi-squared test, both using the SAS program. The RT average was 39.4°C. Cows with RT ? 39.4°C had lower CR than cows with RT < 39.4°C (25.78% vs. 32.54%; P = 0.0096). During spring-summer, cows had higher RT (39.44°C ± 0.025 vs. 39.27°C ± 0.022; P < 0.0001) and lower CR (25.49% vs. 31.75%; P = 0.0146) compared with autumn-winter. Cows inseminated in the morning had lower RT (38.96°C ± 0.022 vs. 39.60°C ± 0.018; P < 0.0001) and higher CR (32.86% vs. 26.06%; P = 0.0102) than cows inseminated in the afternoon. In conclusion, crossbred dairy cows with rectal temperature equal to or greater than 39.4°C had lower conception rate. Moreover, rectal temperature and conception rate were affected by seasonality and insemination time.

Author Biographies

Fransérgio Rocha de Souza, Universidade Federal de Uberlândia

M.e em Ciências Veterinárias, Universidade Federal de Uberlândia, UFU, Uberlândia, MG, Brasil.

Carla Cristian Campos, Universidade Federal de Uberlândia

Discente de Doutorado em Ciências Veterinárias, UFU, Uberlândia, MG, Brasil.

Natascha Almeida Marques da Silva, Universidade Federal de Uberlândia UFU

Profª Drª, Faculdade de Medicina Veterinária, UFU, Uberlândia, MG, Brasil.

Ricarda Maria dos Santos, Universidade Federal de Uberlândia

Profª Drª, Faculdade de Medicina Veterinária, UFU, Uberlândia, MG, Brasil.

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Published

2016-02-29

How to Cite

Souza, F. R. de, Campos, C. C., Silva, N. A. M. da, & Santos, R. M. dos. (2016). Influence of seasonality, timing of insemination and rectal temperature on conception rate of crossbred dairy cows. Semina: Ciências Agrárias, 37(1), 155–162. https://doi.org/10.5433/1679-0359.2016v37n1p155

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