FR 26. Feed suplementation with diets based on local resources in postcalving dual purpose cows Guárico state highlands, Venezuela. II. Effect on the reproduction performance

• Carlos Dominguez ^[1] ; Adrian Gonzalez ^[1] ; Jose A. Ureña ^[1] ; Karel Zahalka ^[1]
  1. [1] Universidad Nacional Experimental de los Llanos Centrales Rómulo Gallegos

     Universidad Nacional Experimental de los Llanos Centrales Rómulo Gallegos

     Venezuela

     
• Localización: Archivos Latinoamericanos de Producción Animal, ISSN 1022-1301, ISSN-e 1022-1301, Vol. 5, Nº. Extra 3, 1997 (Ejemplar dedicado a: Proceedings XV ALPA meeting 2)
• Idioma: inglés
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• Resumen

  • Three different rations were compared during 120 days and treir effects on 125 postcalving dual purpose mature cows, weighting 371 ± 37 kg , grazing native pasture and sorghum crop residues, on highland farms at Guárico State, evaluated throught body condition (BC) and reproductive performance. T1 = grazing sorghum crop residues + sugar cane bagasse + molasses + mineral mixture (Control). T2 = T1 + tomatoes wastes (25 %) + urea + sorghum grain residues and Phithecellobium saman + minerals mixture. T3 = T1 + tomato hulls grinded ad libitum. BC was estimated at beginning on the trial and monthly thereafter. Milk progesterone determination was measured weekly using radioinmunoassay technique (RIA). All time-to-event analysis was accomplished using EGRET program through Product-limit method and Proportional Hazards Model. The supplements represented 4.9; 13.69 and 19.94 (Mj/d) of ME for T1, T2 and T3 respectively. There was no diference between T1 (used as a base category by the model) and T2 (P=0.733). The cows from T1 and T2 had 3.85 times more chances on early cyclicity than the cows from T3 during the period. For each 30 days in the postpartum period the cows had 6.95 more chance on the onset of the ovarian activity (P