SciELO - Scientific Electronic Library Online

 
vol.43 suppl.1The effect of dietary lipid saturation and monensin-Na on the CLA content of lambs' meatVariability of indigestible NDF in C3 and C4 forages and implications on the resulting feed energy values and potential microbial protein synthesis in dairy cattle índice de autoresíndice de materiabúsqueda de artículos
Home Pagelista alfabética de revistas  

Servicios Personalizados

Articulo

Indicadores

Links relacionados

  • En proceso de indezaciónCitado por Google
  • En proceso de indezaciónSimilares en Google

Compartir


South African Journal of Animal Science

versión On-line ISSN 2221-4062
versión impresa ISSN 0375-1589

Resumen

ERASMUS, L.J; BESTER, Z  y  COERTZE, R.J. Milk composition as technique to evaluate the relative bioavailability of a liquid rumen protected methionine source. S. Afr. j. anim. sci. [online]. 2013, vol.43, suppl.1, pp.86-92. ISSN 2221-4062.

Rumen protected amino acids (RPAA) are increasingly being used in dairy cattle diet formulation to obtain the required concentrations of lysine and methionine in metabolisable protein for optimal milk and milk protein production. The objective of this study was to evaluate the relative bioavailability of a liquid rumen protected lysine prototype using the milk composition technique. Forty mid-lactation Holstein cows were used in a complete randomised block design experiment and allocated to one of four experimental treatments. The treatments were: (1) Methionine deficient (Met-) diet, (2) Met- diet supplemented with Smartamine M (SMM), (3) Met- diet supplemented with liquid rumen protected prototype (LRPMet) and (4) Met- diet supplemented with DL Met (DLMet), a hydroxyl analogue of methionine. After an adaptation phase all four groups received the Met- diet and thereafter switched over to the four treatments. Cows supplemented with SMM had higher milk protein and milk fat % compared to the other treatments and increased milk casein % significantly when compared to the Met-control treatment. The milk protein percentages were 3.06, 3.25, 2.95 and 3.46 and the milk fat percentages 3.84, 3.93, 3.75 and 4.27 for the Met-, LRPMet, DL Met and SMM treatments, respectively. SMM again proved to be the RPAA with a high relative bioavailability, while the LRPMet failed to elicit any milk yield or milk composition response. The milk composition technique proved to be a simple but effective technique to evaluate the bioavailability of rumen protected products or prototypes.

Palabras clave : Milk composition; rumen protected methionine; amino acids; Holstein cows.

        · texto en Inglés     · Inglés ( pdf )

 

Creative Commons License Todo el contenido de esta revista, excepto dónde está identificado, está bajo una Licencia Creative Commons