Banca de QUALIFICAÇÃO: JOSIANE PEREIRA DOS SANTOS

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE: JOSIANE PEREIRA DOS SANTOS
DATA: 08/08/2019
HORA: 08:30
LOCAL: Sala de Reuniões PPGCV
TÍTULO:

LACTATION PERFORMANCE AND DIET DIGESTIBILITY OF DAIRY COWS FED FIBROLYTIC ENZYMES

PALAVRAS-CHAVES:

feed efficiency, fiber, fungal extract, milk solids, sorting behavior

PÁGINAS: 30
GRANDE ÁREA: Ciências Agrárias
ÁREA: Medicina Veterinária
RESUMO:

This experiment evaluated the effect of a fibrolytic enzyme preparation on lactation
performance, feed efficiency, and diet digestibility of dairy cows. Twenty-eight
Holstein cows (221 ± 83 days in lactation) were individually fed a standardization diet
for 14 days and a treatment diet for 56 days, in a covariate adjusted randomized block
design with repeated measures over time. Treatments were control (CTL) or a
Trichoderma reesei derived fungal extract [VPT, 0.75 mL kg-1 dry matter (DM).
VistaPre-T, AB Vista]. Diets contained (% of DM): 48.3% corn silage, 3.9% oat hay,
8.6% whole cottonseeds, 20.6% ground corn, 15.8% soybean meal, 36.5% NDF, and
29.5% starch. Milk yield and intake were recorded daily, the total tract apparent
digestibility of nutrients and ruminal fermentation profile were evaluated on week eight,
and chewing and sorting behaviors on weeks four and eight. The digestibility of NDF
was 47.6% of intake on VPT and 44.5% on CTL (P = 0.44) and starch digestibility was
93.1% and 94.0% (P = 0.38), respectively. The proportion of intact corn kernels
excreted in feces was 6.2% of intake on VPT and 5.9% on CTL (P = 0.47). Fecal
viscosity and composition did not differ (P ≥ 0.55). The DM intake was 20.7 and 21.2
kg d-1 (P = 0.96), milk yield was 26.3 and 26.4 kg d-1 (P = 0.44), and the ratio of milk
to DM intake was 1.34 and 1.33 (P = 0.80) on VPT and CTL, respectively. The VPT
tended to increase milk fat concentration (3.52 vs 3.40%. P = 0.07) and increased milk
protein concentration on weeks six (P = 0.02) and eight (P = 0.04) and total solids
concentration (12.10 vs 11.94%. P = 0.02). The molar proportion of acetate tended to be
increased (P = 0.15) and propionate tended to be reduced (P = 0.11) on VPT, inducing a
trend for increased acetate to propionate ratio (P = 0.10). The VPT tended to increase
plasma urea-N over time (P = 0.06) and increased milk urea-N on week three (P =
0.05), suggesting protease activity. Plasma glucose concentration did not differ (P =
0.17). Treatments had no effect on chewing and ingestion behaviors, the proportion of
intake in periods of the day, and particle size, NDF, and starch sorting behaviors (P ≥
0.20). The supplementation of lactating cows with VPT had no effect on diet
digestibility and feed efficiency, but increased milk solids concentration.

MEMBROS DA BANCA:
Externo ao Programa - CARLA LUIZA DA SILVA AVILA - DZO
Externo ao Programa - ERICK DARLISSON BATISTA - DZO
Externo à Instituição - GUSTAVO AUGUSTO DE ANDRADE - IFSM
Presidente - RENATA APOCALYPSE NOGUEIRA PEREIRA - UFLA
Externo à Instituição - RONALDO BRAGA REIS - UFMG