Milk production responses to altering the dietary ratio of palmitic and oleic acids varies with production level in dairy cows.
J Dairy Sci
; 103(12): 11472-11482, 2020 Dec.
Article
em En
| MEDLINE
| ID: mdl-33069410
ABSTRACT
We evaluated the effects of altering the dietary ratio of palmitic (C160; PA) and oleic (cis-9 C181; OA) acids on production responses of cows with a wide range of milk production (32 to 65 kg/d) in a crossover design experiment with a preliminary period. Thirty-two multiparous Holstein cows (144 ± 54 d in milk) were assigned randomly to a treatment sequence. Treatments were diets supplemented with fatty acid (FA) blends (1.5% of diet dry matter) that provided 80% C160 + 10% cis-9 C181 (PA) and 60% C160 + 30% cis-9 C181 (PA+OA). The corn silage and alfalfa-based diets contained 20.0% forage neutral detergent fiber (NDF), 28.5% starch, and 17.1% crude protein. Treatment periods were 21 d with the final 5 d used for data and sample collection. Treatment did not affect dry matter intake (DMI), milk yield, energy-corrected milk (ECM), body weight, or body weight change. The PA+OA diet increased total, 16-carbon, and 18-carbon FA digestibility compared with the PA diet. Compared with PA+OA, PA increased fat yield (1.97 vs. 1.91 kg/d) and protein yield (1.61 vs. 1.55 kg/d). The PA diet also increased the yield of de novo (448 vs. 428 g/d) and mixed (749 vs. 669 g/d) milk FA and decreased the yield of preformed FA (605 vs. 627 g/d) compared with PA+OA. Interactions were detected between treatment and preliminary milk yield for DMI, total FA intake, 16-carbon FA intake, ECM, 3.5% fat-corrected milk (linear interaction), and a tendency for milk yield (linear interaction); lower-producing cows (<45 kg/d) had increased DMI and ECM on the PA diet, whereas higher-producing cows (>55 kg/d) had increased DMI and ECM on the PA+OA diet. A linear interaction was detected between treatment and preliminary milk yield for mixed milk FA yield (linear interaction) and a tendency for de novo milk FA yield (linear interaction). Our results demonstrate that feeding a fat supplement containing more cis-9 C181 replacing C160 increased production responses (DMI, milk yield, and ECM) in higher-producing cows, but decreased production responses in lower-producing cows.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Lactação
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Bovinos
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Ácidos Oleicos
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Ácido Palmítico
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Dieta
Limite:
Animals
Idioma:
En
Ano de publicação:
2020
Tipo de documento:
Article