Changes in Milk Fat in Response to Dietary Supplementation with Calcium Salts of Trans-18:1 or Conjugated Linoleic Fatty Acids in Lactating Dairy Cows

Abstract

Milk fat was investigated in lactating dairy cows fed diets supplemented with Ca salts of trans fatty acids (Ca-tFA) or Ca salts of conjugated linoleic acids (Ca-CLA). Forty-five Holstein cows (115 days in milk) were fed a control diet (51% forage; dry matter basis) supplemented with 400 g of EnerG II (Ca salts of palm oil fatty acids) for 2 wk; subsequently, 5 groups of 9 cows each were assigned for 4 wk to the control diet or diets containing 100 g of Ca-CLA or 100, 200, or 400 g of Ca-tFA in a randomized block design. Treatments had no effect on dry matter intake, milk production, protein, lactose, or somatic cell count. Milk fat percentage was reduced from 3.39% in controls to 3.30, 3.04, and 2.98%, respectively, by the Ca-tFA diets and to 2.54% by the Ca-CLA diet. Milk fat yield (1.24 kg/d in controls) was decreased by 60, 130, and 190 g/d with increasing dose of Ca-tFA and by 290 g/d with the Ca-CLA supplement. Consistent with increased endogenous synthesis of cis-9-containing CLA from precursors provided by the Ca-tFA diets, total CLA were similar in milk of cows fed Ca-CLA or Ca-tFA. Compared with controls, the Ca-CLA diet increased trans-10, cis-12-18:2 yield in milk, without altering levels of trans-18:1 isomers. In contrast, yields of most trans-18:1 isomers were elevated in milk of cows fed Ca-tFA diets, whereas yields of trans-10, cis-12-18:2 remained similar to control values. We conclude that milk fat depression can occur without an increase in trans-10, cis-12-18:2 in milk and that other components, perhaps the trans-10-18:1 isomer, may be involved.

Production performance and pattern of milk fat depression of high-yielding dairy cows supplemented with encapsulated conjugated linoleic acid

“…In this study, daily supplementation of 4.7 g/cow of the trans-10, cis-12 CLA reduced 13% and 9% content and yield of milk fat, respectively, which is very similar to the report of Giesy et al (2002) in which supplementation of 4.4 g/day of trans-10, cis-12 CLA decreased 16.2% and 11.6% milk fat percentage and yield, respectively. However, supplementation of 4.65 g of trans-10, cis-12 CLA/day decreased milk fat content and yield by 25% (Piperova et al, 2004). In this study, the concentration of trans-10, cis-12 CLA yield in milk in the E-CLA group was 2.1-fold higher than in the controls (0.21 v. 0.44 g/day, respectively; Table 6), whereas in Piperova et al (2004), the yield of this isomer in the CLA supplemented group was threefold higher than in the control (0.09 v. 0.25 g/day, respectively).…”

“…In several studies in which cows were fed a variety of CLA supplements in early or mid-lactation, no effect on DMI was observed (Piperova et al, 2004;Castañ eda-Gutié rrez et al, 2005;Castañ eda-Gutié rrez et al, 2007;Odens et al, 2007). However, a trend for lower intake was observed in cows fed calcium salts of CLA in early lactation (Selberg et al, 2004) or abomasally infused with CLA supplements (Baumgard et al, 2000).…”

“…Although the decreased fat synthesis in CLA-supplemented cows may shift the production toward milk yield, in the majority of the reports no milk yield responses were reported with feeding CLA supplements in mid- (Piperova et al, 2004) or early lactation (Selberg et al, 2004;Castañ eda-Gutiérrez et al, 2005;Castañ eda-Gutiérrez et al, 2007). However, other reports in which CLA was fed during early lactation observed enhanced milk yield in the CLA-supplemented cows (Giesy et al, 1999;Bernal-Santos Moallem, Lehrer, Zachut, Livshitz and Yacoby et al, 2003;Shingfield et al, 2004;de Veth et al, 2005) or mid-lactation cows limited in energy supply 2.6% (de Veth et al, 2006).…”

“…It was also proposed by Piperova et al (2004) that trans-10 18:1 might independently be involved in MFD. In a report by Lock et al (2007), abomasal infusion of 42.6 g of trans-10 18:1/day had no effect on milk fat secretion; however, in a recent study by Shingfield et al (2009), higher amount of trans-10 18:1/day (92.1 g/day) abomasal infusion resulted in 21.3% and 19.5% reductions in milk fat content and yield, respectively.…”

Recent advances in the regulation of milk fat synthesis

“…Traditionally, partially hydrogenated vegetable oils (PHVO) have been used to represent an enriched preparation of a range of trans-C18:1 FA, and abomasal infusion of 300 to 750 g/day of PHVO caused a reduction in milk fat (Astrup et al, 1976;Selner and Schultz, 1980;Gaynor et al, 1994;Romo et al, 1996). Calcium salts of PHVO (100 to 400 g/day) have also been fed and milk fat yield was modestly reduced (5% to 15%) in one study (Piperova et al, 2004) and unaffected in another (Selberg et al, 2004). The observed milk fat decrease from PHVO has routinely been attributed to trans-18:1 FA; however, trans-C18:1 represent only about 40% to 60% of the total FA in PHVO, and many other unusual FA isomers, including CLAs, are formed in the production of PHVO (Banni et al, 1994;Jung and Ha, 1999).…”