Management options to accelerate growth rate and reduce age at first calving in Friesian–Boran crossbred heifers

Abstract

Two experiments were conducted simultaneously to evaluate the effects of different concentrates to roughage ratios on growth performance and attainment of puberty in Friesian-Boran crossbred heifers. Weaned 50% Friesian-Boran crossbred female calves were used in both experiments with 25 and 20 calves in experiments I and II, respectively. In experiment I, the calves were offered diets with concentrate to roughage ratios of 50:50 (treatment 1) or 30:70 (treatment 2). In experiment II, the calves grazed for 8 h a day and supplemented with 2 kg hay and 1 kg concentrate per head per day (treatment 1) or only 2 kg hay per head per day (treatment 2). The concentrate mixture was composed of 34% wheat bran, 31% wheat middling, 31% noug cake, 3% limestone, and 1% salt. In experiment I, heifers fed a ration with 50% concentrate and 50% roughage had higher (P < 0.05) daily body weight gain (0.532 kg) and attained puberty at 221 kg (65% of the mature body weight) in 15 months, while heifers fed a diet with 30% concentrate and 70% roughage gained 0.434 kg/day and reached puberty at 247 kg (70% of the mature body weight), about 3 months later. Heifers in treatments 1 and 2 of experiment II reached puberty 5 and 12 months later, respectively, than those in experiment I. In experiment II, heifers given 1 kg of concentrate supplement had higher (P < 0.05) daily body weight gain (0.346 kg) than those given only 2 kg hay in addition to grazing (0.278 kg). Growth rate of crossbred heifers was enhanced and age at puberty was reduced by changing the rearing management from outdoor to indoor and with increasing level of concentrate in the ration. This helps to bring the dairy heifer into production earlier and enhance to the overall productivity of the dairy industry.

Correlation Between Age, Weight and Body Measures at First Pregnancy of Nellore Heifers

“…Oliveira et al (2009), working with 19-to-24-month-old heifers obtained a pregnancy rate of 25% when the females were not stimulated by the presence of bulls during re-breeding and a pregnancy rate of 66% for the females stimulated by bulls. According to Vaz & Lobato et al (2010) and Gojjam et al (2011) another reason for the variations in the rate of pregnancy may be attributed to the effect(s) of the weight or weight gain of the animals.…”

“…In addition, morphometric measures provide supplementary information used to determine genetic and phenotypic trends in the development of the animals over the years, and which may be effective to visualize and monitor the body characteristics directly associated with the reproduction and re-breeding of the animals (Gusmão Filho et al, 2009).…”

Feed Intake of Growing Dairy Heifers Raised under Tropical Conditions: A Model Evaluation Using Meta-Analysis

“…The final database was developed using data from 61 studies ( n = 230 treatment means) of dairy heifers ( n = 1513 heifers). A list of the selected studies is provided in Supplementary Material S1 (Table S1 [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 , 64 ...…”

<b>Influência da adição de gordura protegida na dieta de novilhas Nelore (<i>Bos taurus indicus</i>) no estabelecimento da puberdade e da ciclicidade pós-parto</b>

“…A nutrição pós desmame desempenha papel crítico na determinação da idade à puberdade (THALLMAN et al, 1999). A influência de diferentes tipos de dietas no período pós desmame tem sido bastante estudada (GASSER et al, 1996;GOJJAM et al, 2011 peso vivo e menor ganho de peso no final do pós-parto.…”

“…A nutrição pós desmame desempenha papel crítico na determinação da idade à puberdade (THALLMAN et al, 1999). A influência de diferentes tipos de dietas no período pós desmame tem sido bastante estudada (GASSER et al, 1996;GOJJAM et al, 2011 (STAPLES et al, 1998, CHENG et al, 2001. No entanto, outros estudos demonstraram que a suplementação de vacas após o parto com ácido linoleico aumentou as concentrações circulantes de metabólitos da PGF2α e reduziu a taxa de prenhez (FILLEY et al, 2000;GRANT et al, 2005).…”