Energy metabolism and partition of lactating Zebu and crossbred Zebu cows in different planes of nutrition

Abstract

The aim of this study was to determine the energy metabolism and partition of lactating Gyr and F1 Holstein x Gyr (F1 HxG) cows in different planes of nutrition. Six F1 HxG and six Gyr cows with 130 days in milking (DIM) fed corn silage and concentrate were evaluated. The experiment consisted of four periods with different levels of feeding: 1st ad libitum dry matter intake (DMI) and the others with 5, 10 and 20% restricted DMI, related to the first one. An apparent digestibility assay was performed before measurements in the respiration chamber. Total feces were collected for three days. The cows were confined for 24h in the chamber in each period to determine methane and heat production (HP). F1 HxG had higher gross energy intake (GEI), metabolisable energy intake (MEI) and digestible energy intake (DEI). GE lost in feces was higher in F1 HxG (23.7% GEI) than in Gyr (20.5%) cows. Energy lost as methane and urine was similar between the groups. The metabolisability (q) was 0.67, and the efficiency of converting ME to NE (k) was 0.56. There was no difference in the energy requirements for maintenance between breeds (426.6 MJ/kg BW0,75 average value). The energy requirements for lactation were higher in F1 HxG animals due to the higher volume of milk produced, since there was no difference in energy requirements for production of one kg of milk.

Effects of Feeding Level and Breed Composition on Intake, Digestibility, and Methane Emissions of Dairy Heifers

“…These BCs are the main basis of the Brazilian dairy herd and research efforts on genetic selection have been showing significant increases in milk production. Due the dual purpose of the Zebu crossbred, they may reach high body condition scores, which can lead to calving problems and future lactation performance [7]. However, our results indicated that Holstein heifers fed at MFL demonstrated a higher FE, which means that the nutrients may be used more efficiently for the basal metabolism and product formation.…”

“…Data comparing the performance of different BCs of Holstein × Gyr is not consistent due to the large influence of production systems, diet composition, and genetic variation found in tropical countries. Studies using animals with standardized genetics, age, and physiological state is warranted [7,8]. Better performance estimates are crucial for dairy operations to achieve adequate and more predictable animal performance, avoiding inefficient use of nutrients and resources.…”

Energy requirements for pregnant dairy cows

“…The Brazilian dairy herd is composed of approximately 70% of Holstein × Gyr animals [ 9 , 10 ] and this crossbred has greater milk production than the Gyr breed itself. This greater milk production is likely a result of heterosis, which incorporates the best characteristics of each breed; milk production from Holstein and adaptability to tropical climate from Gyr [ 10 ].…”

“…The Brazilian dairy herd is composed of approximately 70% of Holstein × Gyr animals [ 9 , 10 ] and this crossbred has greater milk production than the Gyr breed itself. This greater milk production is likely a result of heterosis, which incorporates the best characteristics of each breed; milk production from Holstein and adaptability to tropical climate from Gyr [ 10 ]. In a meta-analysis, Oliveira [ 11 ] found lower maintenance requirements and lower efficiency for milk production of crossbred Bos taurus × Bos indicus , compared to Bos taurus breeds.…”

Perfil De La Curva De Lactación Y Producción Láctea Comercial en Vacas Cebuínas Y Cruzadas en Fincas Lecheras Con Baja Tecnología en El Trópico

“…Las vacas cebuínas y cruzadas Holstein x cebuínas bajo diferentes perfiles de alimentación y nutrición energética restringida mostraron que utilizan la energía a medida que aumenta la producción lechera (Araujo et al, 2018).…”