Nutrient requirements of energy and protein for Holstein × Zebu bulls finished in feedlot

Abstract

The objective of this study was to estimate the nutritional requirements of energy and protein in crossbred (Holstein × Zebu) bulls. An experiment of comparative slaughter was conducted with 44 (24 months old) crossbred bulls of 338 ± 39 kg. Bulls were randomly separated as follows: four bulls to the control group, four bulls to the maintenance level group and 36 bulls were fed ad libitum. Corn silage (CS) and sugar cane in natura (SC) at 60 or 40% of dry matter (DM) of total diets were utilized in the diets. The bulls of the last group were randomly assigned to one of six different diets: 1) 60CS:40C(84 days); 2) 60CS:40C (42 days) and 40CS:60C (42 days); 3) 40CS:60C (84 days); 4) 60SC:40C (84 days); 5) 60SC:40C (42 days), and 40SC:60C (42 days), and 6) 40SC:60C (84 days). At the end of the experiment, bulls were slaughtered at Universidade Federal de Viçosa for estimation of the empty body weight. One sample located between the 9 th and the 11 th ribs of each bull was taken and completely dissected for estimation of the empty body composition using equations developed by BR-CORTE 2010. The data were analyzed as nonlinear models built by means of command NLIN of SAS (version 9.2), adjusted by the method of Gauss-Newton. For all the tests, 0.05 was utilized as critical level for probability of type I error. The net (NE m ) and metabolizable (ME m ) energy requirements for maintenance were 78. libitum. Foram utilizadas a silagem de milho (SM) e a cana-de-açúcar in natura (CA) nas proporções de 60 ou 40% na base da matéria seca (MS) total das dietas. As seis dietas experimentais foram constituídas da seguinte forma: 1) 60 SM: 40% de concentrado (C) durante 84 dias; 2) 60SM: 40C (42 dias) e 40SM:60C (42 dias); 3) 40SM:60C (84 dias); 4) 60CA:40C (84 dias); 5) 60CA:40C (42 dias) e 40CA:60C (42 dias) e 6) 40CA:60C (84 dias). Ao final do experimento, todos os animais foram abatidos para determinação do peso de corpo vazio (PCVZ). Uma amostra compreendida entre a 9ª e a 11ª costelas da meia carcaça esquerda foi retirada e completamente dissecada para a estimação da composição química do PCVZ utilizando as equações descritas no BR-CORTE em 2010. Os dados foram analisados como modelos não lineares elaborados por médias do comando NLIN do SAS (versão 9.2), ajustados pelo método de Gauss-Newton. Para todos os testes, 0.05 foi utilizado como nível crítico de probabilidade para o erro tipo I. As exigências de energia líquida (EL m ) e metabolizável (EM m ), para mantença foram de 78,7 e 114,2 kcal/PCVZ 0,75 /dia, respectivamente. A k m foi de 0,6891. As equações obtidas para as exigências líquidas para ganho de energia (EL g ) e proteína (PL g ) foram: EL g (Mcal/dia) = 0,0493 × PCVZ 0,75 × GPCVZ 1,0013 e PL g (g/dia) = 279,19 × GPCVZ -22,8691 × ER, respectivamente. A k g foi de 0,4634. As eficiências de utilização da energia metabolizável para a deposição de proteína e gordura foram de 0,2048 e 0,8848, respectivamente. O modelo obtido para a percentagem de energia retida na forma de proteína (%ER p ) foi: %ER p = 1,7...

Energy and protein requirements of crossbred cattle in feedlot

“…In other words, under the present study conditions, the net requirements for daily gain of 1 kg of BW were equivalent to the requirements for daily gain of 0.95 kg of EBW. The factor of 0.95 is close to the one recommended by NRC (2000) for cattle in general and by Backes et al (2005) for crossbred Holstein x Zebu cattle (factor of 0.96) as well as the factor found by Silva et al (2002) and Prados (2012) Porto et al (2012), which was 71.9 kcal EBW -0.75 day -1 for pastureraised Nelore x Holstein crossbreds, and by Prados (2012) and Rotta et al (2013), which were 68.9 and 78.7 kcal EBW -0.75 day -1 , respectively, for Holstein x Zebu crossbreds in confinement.…”

“…This value is less than the that estimated by Ferrell and Jenkins (1998) for purebred sires and their crossbred offspring (65 to 69%); by Valadares Filho et al (2006) for Zebu bulls (66%); by Prados (2012) and Rotta et al (2013) for Holstein x Zebu crossbreds in confinement (76.41% and 68.91%, respectively) and by Costa e Silva et al (2012) and Marcondes et al (2011a) for confined Nellore purebreds and crossbred Nellore x Angus and Nellore x Simmental bulls, respectively (67%). However, the value found in the present study is higher than the one estimated by Porto et al (2012), which was 58% for pasture-raised Nellore x Holstein crossbreds.…”

Energy requirements for pregnant dairy cows

“…Nonetheless, we recommend a k g of 41.9% for Holstein × Gyr adult cows. We also suggest, based on our results and previous literature [35,36,37] that the k g reported in NRC [6] should be reviewed, because it might overestimate k g for transition cows. The efficiency of utilization of body store reserves for milk production in early lactation is markedly higher than the efficiency of utilizing dietary metabolizable energy for tissue energy gain [32,38].…”

The impact of dietary sugarcane addition to finishing diets on performance, apparent digestibility, and fatty acid composition of Holstein × Zebu bulls1

“…The nutrient requirements for ME and CP calculated according to Rotta et al (2013) are presented in Table 5 According to the nutrient requirements and the ME and CP intakes, it is possible to verify that the nutrient balance in this study was positive for all treatments evaluated. However, for CP, the balance was 0.00 for all treatments, except for CSR and CS40:60 (values for these treatments were negative but close to 0.00).…”

“…According to previous studies (Prado et al, 2008a;Rotta et al, 2009;Oliveira et al, 2012;Freitas et al, 2014), the chemical composition of meat is only slightly influenced by diet. Prado et al (2008a) Rotta et al (2013). observed.…”