Designing Statistical Models for Holstein Rearing Heifers' Weight Estimation from Birth to 15 Months Old Using Body Measurements

Luca Turini; Giuseppe Conte; Francesca Bonelli; Alessio Madrigali; Brenno Marani; Micaela Sgorbini; Marcello Mele

doi:10.3390/ani11071846

Designing Statistical Models for Holstein Rearing Heifers' Weight Estimation from Birth to 15 Months Old Using Body Measurements

Animals (Basel). 2021 Jun 22;11(7):1846. doi: 10.3390/ani11071846.

Authors

Luca Turini^{1

2

3}, Giuseppe Conte^{2

4}, Francesca Bonelli^{1

2}, Alessio Madrigali¹, Brenno Marani¹, Micaela Sgorbini^{1

2}, Marcello Mele^{2

4}

Affiliations

¹ Department of Veterinary Sciences, University of Pisa, 56124 Pisa, Italy.
² Centro di Ricerche Agro-Ambientali "E. Avanzi", University of Pisa, 56122 Pisa, Italy.
³ Istituto Zooprofilattico Sperimentale del Lazio e della Toscana 'M. Aleandri', 00178 Rome, Italy.
⁴ Department of Agriculture, Food and Environment, University of Pisa, 56124 Pisa, Italy.

Abstract

Body measurements could be used to estimate body weight (BW) with no need for a scale. The aim was to estimate heifers weight based on their body dimension characteristics. Twenty-five Holstein heifers represent the study group (SG); another 13 animals were evaluated as a validation group (VG). All the heifers were weighed (BW) and their wither height (WH), shin circumference (SC), heart girth circumference (HG), body length (BL), hip width (HW) and body condition score (BCS) were measured immediately after birth, and then weekly until 2 months and monthly until 15 months old. Equations were built with a stepwise regression in order to estimate the BW at each time using body measures for the SG. A linear regression was applied to evaluate the relationship between the estimated BW and the real BW. Equations found were to be statistically significant (r² = 0.688 to 0.894; p < 0.0001). Three variables or fewer were needed for BW estimation a total of 11/23 times. Regression analysis indicated that the use of HG was promising in all the equations built for BW estimation. These models were feasible in the field; further studies will evaluate possible modifications to our equations based on different growing rate targets.

Keywords: body condition score; body length; body measure; estimated body weight; heart girth circumference; heifer; hip width; shin circumference; wither height.