Effects of altering energy and protein supply to dairy cows during the dry period. 1. Intake, body condition, and milk production.
J Dairy Sci
; 83(8): 1782-94, 2000 Aug.
Article
em En
| MEDLINE
| ID: mdl-10984155
ABSTRACT
We used 48 Holstein-Friesian cows to investigate the effects of altering energy and protein supply to dry cows. Cows were fed one of three diets for 6 wk prior to parturition (a) a 6040 (DM basis) mixture of grass silage with barley straw ad libitum; (b) grass silage ad libitum; or (c) 0.5 kg/d of prairie meal with grass silage ad libitum. The standard lactation diet was a flat-rate allocation of concentrates and grass silage ad libitum. We evaluated dry-period diets using four dry fistulated cows; rumen pH remained high (mean = 6.6) and ammonia concentrations followed N intake. The inclusion of straw reduced apparent ruminal digestion of OM, N, and NDF as well as microbial protein yield, though microbial yield per unit of OM apparently digested in the rumen remained unchanged. Voluntary intake of forage was reduced by the inclusion of straw, while the inclusion of prairie meal had little effect. The decline in intake as calving approached was lower with the silage and straw mix diet. There were large differences in the BW change over the final 5 wk of the dry period, although the opposite effect was seen in early lactation, and differences in BW and body condition score were small by lactation wk 22. Despite the substantial differences in nutrient supply and effects on body reserves, there was little effect of dry-period diet on subsequent performance. Lower forage intakes and yields of protein and lactose were confined to the first month of lactation for cows previously offered straw.
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Base de dados:
MEDLINE
Assunto principal:
Ingestão de Energia
/
Bovinos
/
Proteínas Alimentares
/
Nível de Saúde
/
Leite
/
Dieta
Limite:
Animals
/
Pregnancy
Idioma:
En
Ano de publicação:
2000
Tipo de documento:
Article