Resumo

ELIZONDO-SALAZAR, Jorge Alberto  e  JIMENEZ-CASTRO, José Pablo. Phosphorous balance on Costa Rican dairy farms. Agron. Costarricense [online]. 2014, vol.38, n.1, pp.189-197. ISSN 0377-9424.

The objective was to quantify P use in 11 dairy farms located in the provinces of San Jose, Cartago and Alajuela. Data such as feed purchases, milk sales, purchase and removal of animals between January and December 2010 were used. In order to evaluate the use of P, three indicators that allowed analyzing farm efficiency were used. Total number of animals ranged from 39 to 242. The average annual milk production was 300 880 kg. Farm area varied between 1 and 116 ha. The 11 farms imported on the average 1214 (±1036) kg of phosphorous: 70% came from feed, 16% from fertilizers and 14% from mineral supplements. The farms exported 294 (±219) kg of phosphorous, of which 90% was exported in milk sold and only 10% in animals sold. Total P exported ranged between 136 and 876 kg. Farms imported 4.1 (± 0.8) g.kg^-1  P of milk produced. In general, P balance was positive for all farms, indicating that more P entered the farm that came out in the form of product, showing that 65% of imported P remained on the farms. Strategies to reduce P excretion should be aimed at reducing P in the diets, since the largest P input is through imported feed.

Palavras-chave : Nutrient balance; nutrients; environmental pollution; eutriphication; animal nutrition.

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