Suplementação de vacas lactantes com gérmen integral de milho
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Data
2014-06-30
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Universidade Federal de Goiás
Resumo
The purpose of this study was to evaluate the effect of replacing corn grain by
integral corn germen in the diet for lactating cows using five levels of whole corn
germ intake, on dry matter basis (0.0; 6.7; 13.5; 20.1 and 26.9 %) on dry matter
intake, digestibility, ingestive performance, average particle size, non -degraded
fraction, ruminal parameters, milk production and composition, feeding efficiency,
energy concentration and lactation energy. In order to do so, five multiparous
crossbred cows of 490 kg body weight were tested, 100 days after postpartum and
averaging 26 Kg milk/day. Each experimental period lasted 21 days, with 13 days
for adaptation to the diet and eight days for sample collection. Dry matter intake
took place during the whole period of sample collection. To determine digestibility,
a titanium dioxide external marker was placed directly into the rumen through a
ruminal cannula and faeces were collected between the 16 and 18 days at each
experimental period and. For the determination of the ingestive performance, on
the 14 and 15 days, in five minute intervals, the events spent in leisure, ingestion
and rumination. In DM and FDN analyses from the non-degradable fraction in situ,
Tifton 85 hay was used at 24 and in 48 hours to check changes in ruminal
environment. Milk production and samples for analyses of lactose, protein, ureic
nitrogen and fat were collected on the 15, 17, 19, and 21 days of each
experimental period. The experiment was arranged in a Latin square, and the
variables apparent digestibility, ingestive performance, milk production and
composition, ingestible dry matter, particle average size, non-degradable fraction,
feeding efficiency, energy concentration, lactating energy and rum inal parameters
were evaluated using polynomial regression. The regression models were
subjected to analysis of variance considering the latin square design with test for
lack of adjustment. The models where the regressors were significant and the lack
of adjustment not significant were selected adopting the 5% level of significance.
Pearson´s correlations were performed among all variables. Statistical analyses
were performed using the software R. Ruminal liquid samples were collected
manually at various sites of the rumen and filtered in gauze to determine pH, NNH3
and AGCC. The replacement of corn by whole corn germ did not cause any
changes (P>0,05) in the ingestive performance , pH and N-NH3
. Milk production,
protein content, lactose, protein:fart ratio and feeding efficiency increased
(P<0.05), and a linear reduction (P<0,05) was observed in fat percentage and in
energy concentration with lipids added to the diet. The diet with 26.9% of lipids
added in the DM did not promote negative effect on the variables analyzed;
suggesting that whole corn germ can be a substitute for corn in the diet of milking
cows producing 26 Kg of milk.
Descrição
Palavras-chave
Ácidos graxos , Amido , Coproduto , Metabolismo , Rúmen , Fat acids , Metabolism , Rumen , Starch , Byproduct
Citação
MACHADO, Alan Soares. Suplementação de vacas lactantes com gérmen integral de milho. 2014. 118 f. Tese (Doutorado em Ciência Animal) - Universidade Federal de Goiás, Goiânia, 2014.