Effects of Feeding Level and Breed Composition on Intake, Digestibility, and Methane Emissions of Dairy Heifers
by
, , , and
Tainá Silvestre
1
,
Marina A. Lima
2,
Gustavo B. dos Santos
3,
Luiz G. R. Pereira
4,
Fernanda S. Machado
4,
Thierry R. Tomich
4,
Mariana M. Campos
4,
Arjan Jonker
5,
Paulo H. M. Rodrigues
1,
Virginia L. N. Brandao
6 and
Marcos I. Marcondes
2,7,* 1
College of Veterinary Medicine and Animal Science, Universidade de São Paulo, Pirassununga 13635–900, São Paulo, Brazil
2
Department of Animal Sciences, Universidade Federal de Viçosa, Viçosa 36570–900, Minas Gerais, Brazil
3
Faculty of Veterinary, Universidade Federal Fluminense, Niterói 24220–900, Rio de Janeiro, Brazil
4
Brazilian Agricultural Research Corporation, Embrapa Gado de Leite, Juiz de Fora 36038–330, Minas Gerais, Brazil
5
Grasslands Research Centre, AgResearch Ltd., Palmerston North 4442, New Zealand
6
Micronutrients USA LCC, Indianapolis, IN 46231, USA
7
Department of Animal Sciences, Washington State University, Pullman, WA 99163, USA
*
Author to whom correspondence should be addressed.
Animals 2021, 11(3), 586; https://doi.org/10.3390/ani11030586
Submission received: 9 December 2020
/
Revised: 28 January 2021
/
Accepted: 11 February 2021
/
Published: 24 February 2021
(This article belongs to the Special Issue Grazing Livestock Systems: Measuring and Mitigating Enteric Methane Emissions)
Simple Summary
The nutrients requirements of dairy cattle is the most used system to formulate dairy cattle diets. However, these guidelines were developed based on research using mostly purebred Holstein in temperate conditions and did not determine nutrient requirements of crossbred Holstein × Gyr or Gyr animals raised in a tropical environment. Studies conducted in tropical conditions demonstrated that breed largely affected the nutrient requirements of crossbred and Gyr cattle, which limits the use of this system. Our objective was to evaluate the effects of two feeding levels and three breed compositions on nutrient intake, digestibility, performance, and methane emissions of prepubertal (10-month-old) dairy heifers. We observed that feeding diets to allow gains of 400 and 800 g/day resulted in greater daily gain than the formulated, overestimating the nutritional requirements of the heifers. Overall, breed composition did not affect dry matter intake, but it did result in differences in nutrients digestibility coefficients and feed efficiency. Feeding prepubertal heifers above maintenance requirements was the main driver in reducing CH4 intensity in confinement conditions.
Abstract
The dairy Nutrients Requirements of Cattle (NRC) was developed using data from purebred Holsteins and it might not accurately predict the performance of crossbred cattle. Our objectives were to evaluate the effects of two feeding levels (FLs) and three breed compositions (BCs) on nutrient intake, digestibility, performance, and methane (CH4) emissions of prepubertal dairy heifers. We used thirty-six heifers from three BCs: purebred Holstein (H), purebred Gyr (G), and F1 Holstein × Gyr (HG). Each BC had 12 animals and the experiment was designed as twelve incomplete three by three Latin squares, in a factorial arrangement three by two, with three BCs and two FLs (400 and 800 g/day). Total tract nutrient digestibility was determined using total fecal collection and DMI was individually measured. The data were analyzed using the PROC MIXED in SAS. Dry matter intake of all nutrients increased from the medium to high feeding level and the nutrients digestibility coefficients did differ among BCs. Achieved body weight gain in the medium FL treatment was greater than those predicted using the NRC, suggesting that crossbred and Gyr heifers have similar performance to Holsteins. Breed composition does not influence body weight gain of confined dairy heifers, but Holstein heifers fed a medium FL had higher feed efficiency and reduced CH4 emissions intensity.
