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Titolo:
Effect of sample preparation on in situ estimates of protein degradabilityfor white clover herbages
Autore:
Cohen, DC; Doyle, PT;
Indirizzi:
Agr Victoria, Kyabram Dairy Ctr, Dept Nat Resources & Environm, Kyabram, Vic 3620, Australia Agr Victoria Kyabram Vic Australia 3620 onm, Kyabram, Vic 3620, Australia Dept Nat Resources & Environm, Port Phillip Reg Off, Box Hill, Vic 3128, Australia Dept Nat Resources & Environm Box Hill Vic Australia 3128 3128, Australia
Titolo Testata:
AUSTRALIAN JOURNAL OF EXPERIMENTAL AGRICULTURE
fascicolo: 5, volume: 41, anno: 2001,
pagine: 619 - 624
SICI:
0816-1089(2001)41:5<619:EOSPOI>2.0.ZU;2-B
Fonte:
ISI
Lingua:
ENG
Soggetto:
INFRARED REFLECTANCE SPECTROSCOPY; NITROGEN DEGRADABILITY; CHEMICAL-COMPOSITION; RUMEN; COWS; PRODUCTIVITY; DIGESTION; RYEGRASS;
Keywords:
dairy cows; freeze-dried; oven-dried; fresh; minced;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Agriculture,Biology & Environmental Sciences
Citazioni:
31
Recensione:
Indirizzi per estratti:
Indirizzo: Doyle, PT Agr Victoria, Kyabram Dairy Ctr, Dept Nat Resources & Environm, 120 Cooma Rd, Kyabram, Vic 3620, Australia Agr Victoria 120 Cooma Rd Kyabram Vic Australia 3620 , Australia
Citazione:
D.C. Cohen e P.T. Doyle, "Effect of sample preparation on in situ estimates of protein degradabilityfor white clover herbages", AUST J EX A, 41(5), 2001, pp. 619-624

Abstract

The amount of crude protein in white clover solubilised during ingestion by cows was determined by collecting swallowed boluses in rumen fistulated cows. Six experiments were then conducted to determine the effects of samplepreparation on in situ estimates of rumen degradability of crude protein in white clover (Trifolium repens L.) herbages. Different methods of preparation were compared with chopped fresh herbage, a recommended method when this type of feed is incubated in situ. Samples of white clover were either: (i) chopped fresh to 10 mm lengths (FRS), (ii) frozen, freeze-dried and ground (FRZ/D), (iii) oven-dried at 45 degreesC for 48 h and ground (OD45C), (iv) oven-dried at 60 degreesC for 48 h and ground (OD60C), or (v) minced fresh in a food processor (MNC). The immediate solubilities of crude protein from MNC preparations most closely approximated measures of the proportion (0.28-0.37) of crude protein solubilised during ingestion by cows, while immediate solubilities of crude protein from FRS preparations were low (0.09-0.19). The effective rumen degradability of protein for FRS was lower (P<0.05) than for MNC, FRZ/D or theoven-dried preparations. The effects of the method of preparation of fresh clover on estimates of rumen degradable protein and undegraded dietary protein were compared assuming cows were producing >15 L milk/day. In the 2 experiments comparing FRS and MNC preparations, the average estimates of rumen degradable protein and undegraded dietary protein were 158 and 83 g/ kg DM, respectively, for FRS,compared with 189 and 52 g/ kg DM for MNC. Over the 4 experiments comparing fresh and dried preparations, estimates of rumen degradable protein and undegraded dietary protein for FRS were 140 and 101 g/kg DM, respectively, and differed from those for FRZ/D of 156 and 70 g/kg DM. The implications ofsuch differences have been discussed in relation to use of the in situ technique. It was concluded that no method of sample preparation will be idealand it is likely the preferred method of sample preparation for in situ studies will vary for fresh herbages compared with conserved forages and concentrates.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 09/04/20 alle ore 00:27:09