ABSTRACT:
To evaluate the effect of soybeans roasted at different
temperatures on milk yield and milk fatty acid composition,
8 (4 multiparous and 4 primiparous) mid-lactation
Holstein cows (42.9 پ} 3 kg/d of milk) were assigned to
a replicated 4 × 4 Latin square design. The control diet
(CON) contained lignosulfonate-treated soybean meal
(as a source of rumen-undegradable protein) and calcium
salts of fatty acids (Ca-FA, as a source of energy).
Diets 2, 3, and 4 contained ground soybeans roasted at
115, 130, or 145°C, respectively (as the source of protein
and energy). Dry matter intake (DMI) tended to
be greater for CON compared with the roasted soybean
diets (24.6 vs. 23.3 kg/d). Apparent total-tract digestibilities
of dry matter, organic matter, and crude protein
were not different among the treatments. Actual
and 3.5% fat-corrected milk yield were greater for CON
than for the roasted soybean diets. Milk fat was higher
for soybeans roasted at 130°C than for those roasted at
either 115 or 145°C. No differences were observed between
the CON and the roasted soybean diets, or among
roasting temperatures, on feed efficiency and nitrogen
concentrations in rumen, milk, and plasma. Milk from
cows fed roasted soybeans had more long-chain fatty
acids and fewer medium-chain fatty acids than milk
from cows fed Ca-FA. Compared with milk from cows
fed the CON diet, total milk fat contents of conjugated
linoleic acid, cis-9,trans-11 conjugated linoleic acid, cis-
C18:2, cis-C18:3, and C22:0 were higher for cows fed
the roasted soybean diets. Polyunsaturated fatty acids
and total unsaturated fatty acids were greater in milk
from cows fed roasted soybean diets than in milk from
cows fed CON. Concentrations of C16:0 and saturated
fatty acids in milk fat were greater for CON than for the
roasted soybean diets. Cows fed roasted soybean diets
had lower atherogenic and thrombogenic indices than
cows fed CON. Milk fatty acid composition did not differ
among different roasting temperatures. In summary,
results showed that cows fed CON had higher DMI
and milk yield than cows fed roasted soybean diets.
Among different roasting temperatures (115, 130, and
145°C), soybeans roasted at 115°C led to higher milk
production and lower DMI. Cows fed roasted soybeans,
regardless of the roasting temperature, had more unsaturated
fatty acids in milk. Using roasted soybeans in
dairy cow rations could, therefore, improve the health
indices of milk for human nutrition.
Key words:
roasted soybeans, calcium salts of fatty
acids, milk fatty acids
Publisher: Journal of Dairy Science Volume 99, Issue 7, July 2016, Pages 5422-5435
Quartiles : Q1
IMPACT FACTOR: 3.5
Country: USA
Target Animal: Dairy Cow
Product under study: Lignosulfonate treated soybean meal