Interactions of bST injections with dietary protein sources of different rumen degradability were tested for their effects on milk production and N metabolism. The diet was formulated to contain either 36 or 40% of CP as ruminally undegradable protein. Supplemental CP was a combination of soybean meal and sunﬂower meal (control diet) or a combination of soybean meal and herring meal (low ruminally degradable protein diet). One hundred Italian F riesian dairy cows were randomly divided into four treatment groups: control diet, low ruminally degradable protein diet, control diet plus bST, low ruminally degradable protein diet plus bST. Recombinant bST in a sustained-release formulation (640 mg/28 days) was injected for two cycles. Milk production increased in response to bST but was not inﬂuenced by the low ruminally degradable protein diet. No signiﬁcant bST effects on milk composition were found. Cows fed the diet low in ruminally degradable protein produced milk with lower fat and higher protein percentage. Somatotropin treatment and dietary treatment with low ruminally degradable protein showed additive effects on milk yield and quality parameters. At 7 d postinjection, bST increased plasma NEFA and decreased uric acid, and urea in cows receiving the control or the low ruminally degradable diet; however, bST increased plasma creatinine, and . decrased or-amino N in cows receiving the control diet. The low ruminally degradable protein diet increased plasma uric acid, and lowered plasma NEFA.
Responses of dairy cows to bovine somatotropin and protein sources with different rumen degradability / D. Cattaneo, E. Salimei, F. Rosi, G. Savoini, C.A. Sgoifo Rossi, V. Dell'Orto. - In: ZOOTECNICA E NUTRIZIONE ANIMALE. - ISSN 0390-0487. - 23:5(1997 Oct), pp. 245-255.
|Titolo:||Responses of dairy cows to bovine somatotropin and protein sources with different rumen degradability|
SGOIFO ROSSI, CARLO ANGELO (Penultimo)
DELL'ORTO, VITTORIO (Ultimo)
|Parole Chiave:||somatotropin ; protein sources ; milk composition ; N metabolism|
|Settore Scientifico Disciplinare:||Settore AGR/18 - Nutrizione e Alimentazione Animale|
Settore VET/01 - Anatomia degli Animali Domestici
|Data di pubblicazione:||ott-1997|
|Appare nelle tipologie:||01 - Articolo su periodico|