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Can housing system affect automated estrus detection in Holstein dairy heifers?

G. Mazon



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Can housing system affect automated estrus detection in Holstein dairy heifers?
R. A. Figueiredo1, G. Mazon*2, J. H. C. Costa2. 1Embrapa Genetic Resources and Biotechnology Brasilia, DF, Brazil, 2University of Kentucky Lexington, KY.

The objective of this study was to evaluate the effects of dairy cattle housing systems (HS) on automated estrus detection in Holstein dairy heifers. Thirty-six heifers (14.7 � 2.2 mo old; 297.7 � 65.2 kg) were evaluated from March to June 2019. Heifers were fitted with a behavior monitoring collar (MooMonitor+, Dairymaster, Ireland) and independently randomly assigned in 1 of 3 HS (bedded-pack, BP; freestall, FS; pasture, PA) in a 3x3 Latin Square. Each period lasted 29d before heifers were moved to a different HS. All heifers had 2 wk for habituation, then their estrus was synchronized using a 7d protocol. The protocol started (D0) with CIDR insertion plus GnRH (100 �g). Seven days later (D+7), CIDR was removed, PGF (25mg) was administered, and heifers received an estrus detection patch. Visual observations were conducted (1h/twice a day) and ultrasonography was performed on protocol days −7, +2 and +7 to evaluate the presence and diameter of the largest follicles and CL. True estrus was defined if a heifer was visually observed in standing estrus, had more than 50% of the estrus detection patch activated, and ovulated. Estrus detection rate was 78% and the ovulation rate was 83%. Sensitivity (proportion of heifers in true estrus with an automatic estrus alert), specificity (proportion of heifers not in true estrus without an automatic alert), and accuracy (proportion of heifers that were correctly automatically identified in estrus or not) were calculated for each HS and differences between HS were assessed using a mixed model. Overall sensitivity, specificity, and accuracy of the behavior monitoring collar estrus alerts were 80.8, 79.2, and 91.7%, respectively. No effect of the period was found (P > 0.41). There were no differences in sensitivity between HS (BP = 96.7 � 4.2, FS = 93.0 � 4.2, PA = 95.8 � 4.2; P = 0.77), or in specificity between HS (BP = 83.3 � 19.9, FS = 88.9 � 19.9, PA = 50.0 � 19.9; P = 0.41). Lastly, no differences in accuracy were found between HS (BP = 94.4 � 6.2, FS = 91.7 � 6.2, PA = 88.9 � 6.2; P = 0.83). In summary, HS did not affect the sensitivity, specificity, and accuracy of the behavior monitoring collar.

Keywords: technology, precision, validation.

Biography: Originally from Belo Horizonte, Brazil, Gustavo is currently a 1st year PhD student at the University of Kentucky under Dr. Joao Costa. Gustavo's PhD is focused on nutritional management strategies using precision dairy technologies. His career goal is to obtain a research and extension focused position at a land grant university.