Evaluation of Ingestive Behavior, Ruminal and Blood Parameters, Performance, and Thermography as a Phenotypic Divergence Markers of Residual Feed Intake in Rearing Dairy Heifers.

Mayara Campos Lombardi,Fernanda Samarini Machado,Hilton Do Carmo Diniz Neto,Sandra Gesteira Coelho,Luiz Gustavo Ribeiro Pereira,Mariana Magalhães Campos,Thierry Ribeiro Tomich

doi:10.3390/ani12030331

Abstract

Simple SummaryThe selection of highly efficient animals will support meeting the world’s future demand for products and food of animal origin. Thus, the identification of efficient animals and an understanding of the mechanisms inherent to this efficiency is fundamental for the progress of breeding systems. In the present study, we identify highly efficient animals for residual feed intake in dairy heifers. This animal category is unexplored in relation to this index. We utilized the classical parameters evaluated in cattle of different ages to carry out the study on these animals.The objectives of this study were: (1) to identify and rank phenotypically divergent animals for residual feed intake (RFI) regarding their efficiency (high: HE or low: LE); (2) to evaluate their relationships with ingestive behavior, ruminal and blood parameters, performance, and infrared thermography; and (3) to determine if such measurements can be used as feed efficiency markers in rearing dairy heifers. Thirty-eight heifers, 143 d ± 4 (Mean ± SD) of age and 108.7 kg ± 17.9 of body weight were used. The animals were fed with a total mixed ration during the 91 d of the trial. A phenotypic divergence of DMI for RFI was observed between −0.358 and 0.337 kg/d for HE and LE, respectively. Dry matter intake (DMI) was lower in the HE (2.5 kg DMI/d vs. 3.1 kg DMI/d), as was the number of visits to the feed bin with consumption (59 vs. 71). Feed intake was the best predictor of said divergence. Water intake and number of visits to the feed bin were presented moderate correlations with RFI. The ruminal fermentation variables, blood metabolites, blood hormones (such as the other ingestive behavior variables), and infrared thermography were not able to accurately predict HE or LE animals.

Highlights

In the search for sustainability, animals that are more efficient at converting food into product are of unquestionable relevance [1,2]
The search for effective and more accessible parameters as predictors of efficiency in residual feed intake (RFI) continues [6]. As this is an unexplored category in RFI, the present study evaluates dairy heifers using the classic parameters found in the literature for the RFI study of cattle at different stages of life
A phenotypic divergence of Dry matter intake (DMI) for RFI was observed between −0.358 and 0.337 kg/d for HE and LE, respectively (p < 0.0001) (Table 2)

Summary

Introduction

In the search for sustainability, animals that are more efficient at converting food into product are of unquestionable relevance [1,2]. The evaluation of feed efficiency can be obtained from measuring indexes such as feed conversion, average daily weight gain (ADG), residual body weight gain, residual feed intake (RFI), residual intake and body weight gain, or a combination of some of these indexes [3,4]. Postweaning calves in dairy cattle were not studied This animal category was very important in the systems, and it needs to be evaluated. In the future, these results could be associated with the RFI in adult cows

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Conclusion