Estrus Prediction Models for Dairy Gyr Heifers

Author(s)

Andrade, Valesca Vilela ^[1] ; Bernardes, Priscila Arrigucci ^[1] ; Vicentini, Rogerio Ribeiro ^[1] ; Oliveira, Andre Penido ^[2] ; Veroneze, Renata ^[2] ; Ujita, Aska ^[1] ; Negrao, Joao Alberto ^[3] ; El Faro, Lenira ^[1]

Affiliation

^[1] Inst Anim Sci, Beef Cattle Res Ctr, Rod Carlos Tonani, Km 92, BR-14174000 Sertaozinho - Brazil

^[2] Agr Res Co Minas Gerais EPAMIG, Rua Afonso Rato 1301, BR-38001970 Uberaba, MG - Brazil

^[3] Univ Sao Paulo, Fac Anim Sci & Food Engn, Av Duque Caxias Norte 225, BR-13635900 Pirassununga - Brazil

• Document type: Journal article
• Source: ANIMALS; v. 11, n. 11 NOV 2021.
• Web of Science Citations: 0

Abstract

Simple SummaryIntraruminal devices are already being used to predict reproductive events in cattle. For this prediction, several models and approaches can be used. The aim of this study was to evaluate changes in rumen reticulum temperature (RRT) and activity (ACT) during estrus in Dairy Gyr heifers and to evaluate different models for estrus prediction. There was an increase in both RRT and ACT in the estrus period compared to the same period on the day before and the day after estrus. Among the mathematical models, Random Forest had the best performance. The present results suggest that RRT and ACT can contribute to the identification of estrus and be of value for improving the reproductive efficiency of Zebu herds in tropical regions.Technological devices are increasingly present in livestock activities, such as identifying the reproductive status of cows. For this, predictive models must be accurate and usable in the productive context. The aims of this study were to evaluate estrus-associated changes in reticulo-rumen temperature (RRT) and activity (ACT) in Dairy Gyr heifers provided by reticulo-rumen boluses and to test the ability of different models for estrus prediction. The RRT and ACT of 45 heifers submitted to estrus synchronization were recorded using reticulo-rumen boluses. The means of RRT and ACT at different time intervals were compared between the day before and the day of estrus manifestation. An analysis of variance of RRT and ACT was performed using mixed models. A second approach employed logistic regression, random forest, and linear discriminant analysis models using RRT, ACT, time of day, and the temperature-humidity index (THI) as predictors. There was an increase in RRT and ACT at estrus (p < 0.05) compared to the same period on the day before and on the day after estrus. The random forest model provided the best performance values with a sensitivity of 51.69% and specificity of 93.1%. The present results suggest that RRT and ACT contribute to the identification of estrus in Dairy Gyr heifers. (AU)

• FAPESP's process: 15/24174-3 - Study of traits related to stress, behavior and reproduction of Gir dairy cows
• Grantee: Lenira El Faro Zadra
• Support Opportunities: Regular Research Grants