Long-term palmitic acid supplementation interacts with parity in lactating dairy cows: Production responses, nutrient digestibility, and energy partitioning

Abstract

The objective of our study was to evaluate the effects of long-term palmitic acid (C16:0) supplementation and parity on production, nutrient digestibility, and energy partitioning of mid-lactation dairy cows. Forty mid-lactation Holstein cows (18 primiparous and 22 multiparous) were used in a block design. Cows were assigned to receive either a control diet containing no supplemental fat (CON) or a C16:0-enriched supplemented diet (PA; 1.5% diet dry matter) fed for 10 wk. Compared with CON, PA increased dry matter intake, milk yield, cumulative milk yield, milk fat content, milk fat yield, 16-carbon milk fatty acid (FA) yield, 3.5% fat-corrected milk yield, and energy-corrected milk yield. Additionally, PA increased body weight change, but did not affect body condition score change compared with CON. A tendency for a treatment by parity interaction was observed for milk yield due to PA increasing milk yield in multiparous but not in primiparous cows. In addition, we observed interactions between treatment and parity for fat-corrected milk, energy-corrected milk, and milk fat yield due to PA increasing these variables to a greater extent in multiparous compared with primiparous cows. Interestingly, we observed an interaction between treatment and parity for body weight change, due to PA increasing body weight change in primiparous but not in multiparous cows. The PA treatment increased dry matter and neutral detergent fiber digestibilities compared with CON. Although PA did not affect 18-carbon FA digestibility, compared with CON, PA decreased 16-carbon and total FA digestibilities and increased total FA intake by 470 g/d and absorbed total FA by 316 g/d. We also observed an interaction between treatment and parity for total absorbed FA due to PA increasing it to a greater extent in multiparous than in primiparous cows. Compared with CON, PA increased apparent energy intake and milk energy output. We observed an interaction between treatment and parity for milk energy output due to PA increasing milk energy output to a greater extent in multiparous than primiparous cows. Additionally, an interaction between treatment and parity was observed for energy output in body reserves due to PA increasing energy output in body reserves in primiparous but not in multiparous cows. In conclusion, production responses of dairy cows to PA were consistent throughout the 10-wk treatment period. In addition, PA supplementation interacted with parity, with production responses increased to a greater extent in multiparous than primiparous cows and energy partitioned to body reserves only increased in primiparous cows.

Milk production and nutrient digestibility responses to triglyceride or fatty acid supplements enriched in palmitic acid

“…We observed that compared with CON, PA treatments reduced the digestibility of 16-carbon FA and total FA. Although Rico et al (2014a) reported that feeding a highly enriched C16:0 supplement had positive effects on 16-carbon and total FA digestibilities of low-producing cows, other studies with high-producing cows have observed reductions in FA digestibility when feeding similar supplements (de Souza et al, 2017;de Souza and Lock, 2018a). In a recent meta-analysis, Boerman et al (2015) observed no reduction in FA digestibility when the duodenal flow of C16:0 increased up to 500 g/d, whereas increasing the duodenal flow of C18:0 to the same level reduced FA digestibility.…”

“…This FA has been reported to increase milk yield, milk fat concentration and yield, and the efficiency of milk production compared with a control diet (Mosley et al, 2007;Lock et al, 2013;de Souza et al, 2017) and with other FA supplements (Rico et al, 2014a,b;de Souza et al, 2018). However, variation in response to C16:0 has also been reported, with some studies reporting no effect of C16:0 supplementation on milk yield (Lock et al, 2013;Rico et al, 2014a), whereas others reported increases in milk yield (Mosley et al, 2007;Piantoni et al, 2013;de Souza and Lock, 2018a). Because the supplements described in the above-mentioned studies were similar in FA composition, understanding factors (e.g., basal diet composition, characteristics of fat supplements) that are associated with variations in production responses may allow for more precise feeding recommendations.…”

Milk production responses to altering the dietary ratio of palmitic and oleic acids varies with production level in dairy cows

“…Understanding the differences between individual FA is crucial to determining optimal dietary FA profiles for cows. Recent research indicates that C16:0 supplementation increases milk fat concentration and yield and NDF digestibility compared with non-FA-supplemented control diets and other FA supplements (de Souza and Lock, 2018b;Western et al, 2020). Boerman et al (2017) fed increasing levels of a C18: 0 -enriched supplement (~93% C18:0) to dairy cows and observed no positive effect on production responses, which was likely associated with the pronounced decrease in total FA digestibility as FA intake increased.…”

Physical characterization of fatty acid supplements with varying enrichments of palmitic and stearic acid by differential scanning calorimetry

“…Supplementing a moderately enriched PA prill (~80 to 85%) with >7% UFA has variable effects on FA digestibility. For example, 2 publications reported decreases in total FA digestibility of <5 percentage units and in C16 FA digestibility <11 percentage units de Souza and Lock, 2018), whereas Rico et al (2014a) reported increased total and C16 FA digestibility with an ~85% PA supplement. The fat supplement used in Rico et al (2014a) was assessed in the present study as stock I (93.0% PA + 4.8% UFA), which had 17.6 J/g (8.1%) lower enthalpy than stock H (96.3% PA + 0.3% UFA).…”

“…Recent work has shown that supplements that are highly enriched in SA and depleted in other SFA or UFA decreased total-tract FA digestibility by over 20 percentage points (Piantoni et al, 2015;Boerman et al, 2017) and those very highly enriched in PA decreased 16-carbon FA digestibility over 17 percentage units (Piantoni et al, 2013). Studies feeding moderately enriched PA (80 to 85%) reported decreases of less than 5 percentage points in total-tract digestibility (de Souza et al, 2017;de Souza and Lock, 2018), and one publication reported an increase in FA digestibility compared with a no-fat control diet (Rico et al, 2014a).…”