EFICIENCIA ALIMENTICIA NETA EN BECERRAS DE LOS GRUPOS RACIALES CRIOLLO ANGUS X CRIOLLO Y HEREFORD X ANGUS.

MEDINA ORTEGA, EDGAR ENRIQUE (2016) EFICIENCIA ALIMENTICIA NETA EN BECERRAS DE LOS GRUPOS RACIALES CRIOLLO ANGUS X CRIOLLO Y HEREFORD X ANGUS. Maestría thesis, UNIVERSIDAD AUTONOMA DE CHIHUAHUA.

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Resumen

Under the conditions of climate change, increased input costs and depletion of resources, improved efficiency and reduced inputs are a priority for sustainability of production. The Chihuahua creole cattle has adapted to difficult conditions of topography, climate and restricted food availability, characteristics of which can be taken advantage of with crossbreeding for meat production. The objective was to evaluate postweaning feed efficiency and its relationship with other performance traits of contemporary Creole (CR), Angus x Criollo (AxC) and Hereford x Angus (HxA) female calves. Twenty eight female calves (10 CR, 10 AxC and 8 HxA) were used with an initial weight of 153 ± 40 kg and 8 ± 1.2 months of age under an individual 56 d feeding performance test, after 14 d of adaptation. An ad libitum diet composed of oat hay, alfalfa, rolled corn, cottonseed meal, molasses, fat and minerals, balanced (NRC; 11.5% CP and 1.48 Mcal ME / kg DM) for a daily gain (GDP) of 600 g was used. Feed was offered daily at 7:00 pm and feed intake (CDA) was calculated by the difference of amount offered minus rejected. Every 14 d, calves were weighed before feed was served. Variables GDP, CDA, feed conversion (CA) and residual feed intake (RFI) were calculated. A single way classification linear model was adjusted to evaluate the fixed racial group effects. Correlations between RFI and other variables were estimated. There was no effect of racial group on RFI or CA (P > 0.05). The averages of GDP and CDBS were different (P <0.05) among racial groups in the HXA>AxC>CR direction. The RFI was positively correlated (P < 0.05) with CDBS (0.21) and CA (0.4), but was independent of body weight and GDP. In conclusion, CDBS is lower in creole and AxC calves than for those in the HXA group, according to their differences in body weight, but feed efficiency evaluated by both RFI and CA, is the same for all evaluated groups under the study conditions.

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