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Effects of dietary supplementation of rumen-protected conjugated linoleic acid in dairy cows during established lactation.
J Dairy Sci. 2002 Oct; 85(10):2609-17.JD

Abstract

Short-term studies (< 5 d) involving abomasal infusion of a mixture of CLA isomers or pure trans-10, cis-12 CLA have demonstrated that supplements of conjugated linoleic acids (CLA) reduce milk fat synthesis during established lactation in dairy cows. Our objective was to assess longer term effects of supplementation during established lactation using a dietary supplement of rumen-protected CLA. Thirty Holstein cows were blocked by parity and received a dietary fat supplement of either Ca-salts of palm oil fatty acids (control) or a mixture of Ca-salts of palm oil fatty acids plus Ca-salts of CLA (CLA treatment). Supplements provided about 90 g/d of fatty acids and were topdressed on the TMR. The CLA supplement provided 30.4 g/d of CLA in which the predominant isomers were: trans-8, cis-10 (9.2%), cis-9, trans-11 (25.1%), trans-10, cis-12 (28.9%), and cis-11, trans-13 (16.1%). All cows were pregnant; treatments were initiated on d 79 of pregnancy (approximately 200 d prepartum) and continued for 140 d until dry off. Twenty-three cows completed the study; those receiving CLA supplement had a lower milk fat test (2.90 versus 3.80%) and a 23% reduction in milk fat yield (927 versus 1201 g/d). Intake of DM, milk yield, and the yield and content of true protein and lactose in milk were unaffected by treatment. Milk fat analysis indicated that the CLA supplement reduced the secretion of fatty acids of all chain lengths. However, effects were proportionally greater on short and medium chain fatty acids, thereby causing a shift in the milk fatty acid composition to a greater content of longer-chain fatty acids. Changes in body weight gain, body condition score, and net energy balance were not significant and imply no differences in cows fed the CLA supplement in replenishment of body reserves in late lactation. Likewise, maintenance of pregnancy, gestation length, and calf birth weight were unaffected by treatment. Overall, feeding a dietary supplement of rumen-protected CLA to pregnant cows over the last 140 d of the lactation cycle resulted in a marked reduction in milk fat content and yield, and a shift in milk fatty acid composition, but other milk components, DMI, maintenance of pregnancy, and cow well-being were unaffected.

Authors+Show Affiliations

Department of Animal Science, Cornell University, Ithaca, NY 14853, USA.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

12416815

Citation

Perfield, J W., et al. "Effects of Dietary Supplementation of Rumen-protected Conjugated Linoleic Acid in Dairy Cows During Established Lactation." Journal of Dairy Science, vol. 85, no. 10, 2002, pp. 2609-17.
Perfield JW, Bernal-Santos G, Overton TR, et al. Effects of dietary supplementation of rumen-protected conjugated linoleic acid in dairy cows during established lactation. J Dairy Sci. 2002;85(10):2609-17.
Perfield, J. W., Bernal-Santos, G., Overton, T. R., & Bauman, D. E. (2002). Effects of dietary supplementation of rumen-protected conjugated linoleic acid in dairy cows during established lactation. Journal of Dairy Science, 85(10), 2609-17.
Perfield JW, et al. Effects of Dietary Supplementation of Rumen-protected Conjugated Linoleic Acid in Dairy Cows During Established Lactation. J Dairy Sci. 2002;85(10):2609-17. PubMed PMID: 12416815.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Effects of dietary supplementation of rumen-protected conjugated linoleic acid in dairy cows during established lactation. AU - Perfield,J W,2nd AU - Bernal-Santos,G, AU - Overton,T R, AU - Bauman,D E, PY - 2002/11/6/pubmed PY - 2003/2/25/medline PY - 2002/11/6/entrez SP - 2609 EP - 17 JF - Journal of dairy science JO - J Dairy Sci VL - 85 IS - 10 N2 - Short-term studies (< 5 d) involving abomasal infusion of a mixture of CLA isomers or pure trans-10, cis-12 CLA have demonstrated that supplements of conjugated linoleic acids (CLA) reduce milk fat synthesis during established lactation in dairy cows. Our objective was to assess longer term effects of supplementation during established lactation using a dietary supplement of rumen-protected CLA. Thirty Holstein cows were blocked by parity and received a dietary fat supplement of either Ca-salts of palm oil fatty acids (control) or a mixture of Ca-salts of palm oil fatty acids plus Ca-salts of CLA (CLA treatment). Supplements provided about 90 g/d of fatty acids and were topdressed on the TMR. The CLA supplement provided 30.4 g/d of CLA in which the predominant isomers were: trans-8, cis-10 (9.2%), cis-9, trans-11 (25.1%), trans-10, cis-12 (28.9%), and cis-11, trans-13 (16.1%). All cows were pregnant; treatments were initiated on d 79 of pregnancy (approximately 200 d prepartum) and continued for 140 d until dry off. Twenty-three cows completed the study; those receiving CLA supplement had a lower milk fat test (2.90 versus 3.80%) and a 23% reduction in milk fat yield (927 versus 1201 g/d). Intake of DM, milk yield, and the yield and content of true protein and lactose in milk were unaffected by treatment. Milk fat analysis indicated that the CLA supplement reduced the secretion of fatty acids of all chain lengths. However, effects were proportionally greater on short and medium chain fatty acids, thereby causing a shift in the milk fatty acid composition to a greater content of longer-chain fatty acids. Changes in body weight gain, body condition score, and net energy balance were not significant and imply no differences in cows fed the CLA supplement in replenishment of body reserves in late lactation. Likewise, maintenance of pregnancy, gestation length, and calf birth weight were unaffected by treatment. Overall, feeding a dietary supplement of rumen-protected CLA to pregnant cows over the last 140 d of the lactation cycle resulted in a marked reduction in milk fat content and yield, and a shift in milk fatty acid composition, but other milk components, DMI, maintenance of pregnancy, and cow well-being were unaffected. SN - 0022-0302 UR - https://www.unboundmedicine.com/medline/citation/12416815/Effects_of_dietary_supplementation_of_rumen_protected_conjugated_linoleic_acid_in_dairy_cows_during_established_lactation_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0022-0302(02)74346-4 DB - PRIME DP - Unbound Medicine ER -