Effect of Prepartum Administration of Monensin in a Controlled-release Capsule on Postpartum Energy Indicators in Lactating Dairy Cows

Abstract

The effects of monensin on the energy metabolism of dairy cows in early lactation were investigated in a large clinical trial that was randomized and double-blinded. A total of 1010 Holstein cows and first lactation heifers were allocated to receive a controlled-release capsule of monensin or a placebo at 3 wk prior to expected calving date. Treatments were randomized across 25 dairy farms located near Guelph, Ontario, Canada. Serum samples obtained at the time of treatment administration and at wk 1, 2, 3, 6, and 9 postcalving were analyzed for beta-hydroxybutyrate, glucose, aspartate aminotransferase, urea, total protein, calcium, and phosphorus. Cows were also assigned a body condition score at the time each sample was obtained. Monensin treatment significantly reduced serum beta-hydroxy-butyrate concentrations at wk 1, 2, and 3 postpartum and significantly raised serum glucose concentrations during wk 1 and 2 of lactation. In addition, monensin treatment significantly reduced the loss of body condition score and decreased serum activity of aspartate aminotransferase during the postpartum period. Concentrations of serum urea were significantly higher during wk 2 and 3 postpartum for the cows that were treated with monensin. Monensin treatment had no effect on the concentrations of calcium, phosphorus, or total protein.

Effects of Flavomycin on Ruminal Fermentation, <em>In Situ</em> Degradability and <em>In Vivo</em> Digestibility in Bovine Fed Sugarcane Diets

“…Flavomycin mainly inhibits two groups of bacterias, ones from the group High Activity of Ammonia Production (HAAP) and also Gram-negative fusobacteria, where both groups have high specific activity of desamination (Edwards et al, 2005). Chen and Russell (1991); Dennis et al (1981); Duffield et al (1998); Funk et al (1986); McGuffey et al (2001); McKain et al (2000); Phipps et al (2000); Ovchinnikov (1979) and Schelling (1984) are trying to characterize the antimicrobial mode of action and clarify how these agents act in digestive efficiency improvement and, consequently, animal productivity.…”

Perfil metabólico e desenvolvimento da glândula mamária de novilhas leiteiras sob manejo para crescimento compensatório

“…Van der Merwe (2001) observou que animais em pastejo consumindo dieta suplementada com monensina apresentaram teor de N-ureico em média 9,77% inferior ao do grupo controle. A ausência de efeito da monensina sobre o teor plasmático de ureia neste estudo corrobora os resultados obtidos por Stephenson et al (1997) e Duffield et al (2001), sugerindo que os efeitos da monensina sobre o metabolismo proteico foram inferiores ao efeito sobre a disponibilidade de glicose. Segundo Stephenson et al (1997), o aumento na disponibilidade proteica proporcionado pela suplementação com ionóforo pode ser pequeno ou a estimativa do teor plasmático de ureia pode não ser suficientemente sensível para detectar diferenças no metabolismo proteico.…”

Efeitos da administração de monensina por meio de cápsulas de liberação controlada no desempenho de vacas Holandesas no início da lactação

“…Esse período é de extrema demanda de energia para estes animais, que reduzem a capacidade de ingestão de alimentos no último terço de gestação e início de lactação, quando seria necessário maior consumo de matéria seca (Duffield, 1997), em virtude do início da lactação e da maior predisposição na mobilização de gordura corpórea (Duffield et al, 1998) e requerimento de nitrogênio (Plaizier, 1997).…”