Effects of partly replacing dietary starch with fiber and fat on milk production and energy partitioning

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Residual feed intake (RFI) is a tool to quantify feed efficiency in livestock and is commonly used to assess feed efficiency independent of production level, body weight (BW), or BW change. Lactating Holstein cows (n=109; 44 primiparous and 65 multiparous), averaging (mean ± standard deviation, SD) 665±77kg of BW, 42±9kg of milk/d, and 120±30 d postpartum, were fed diets of high (HI) or low (LO) starch content in 4 crossover experiments with two 28-d treatment periods. The LO diets were ~40% neutral detergent fiber (NDF) and ~14% starch and the HI diets were ~26% NDF and ~30% starch. Individual dry matter intake (DMI) of a cow was modeled as a function of milk energy output, metabolic BW, body energy change, and fixed effects of parity, experiment, cohort nested within experiment, and diet nested within cohort and experiment; RFI for each cow was the residual error term. Cows were classified as high (>0.5 SD of the mean), medium (±0.5 SD of the mean), or low (<-0.5 SD of the mean) RFI. On average, for the linear model used to determine RFI for individual cows, each unit increase in milk energy output, metabolic BW, or body energy gain was associated with 0.35, 0.09, or 0.05kg increase in DMI, respectively. When compared with LO diets, HI diets increased energy partitioning to body energy gain and tended to increase DMI. The correlation between RFI when cows were fed HI diets and RFI when cows were fed LO diets was 0.73 and was similar across each parity and experiment. Fifty-six percent of cows maintained the same RFI classification (high, medium, or low RFI) and only 4 of 109 cows changed from high RFI to low RFI or vice versa when diets were changed. Milk:feed, income over feed cost, and DMI were also highly repeatable (r=0.72, 0.84, and 0.92, respectively). We achieved significant changes in milk yield and component concentration as well as energy partitioning between HI and LO diets and still determined RFI to be repeatable across diets. We conclude that RFI is reasonably repeatable for a wide range of dietary starch levels fed to mid-lactation cows, so that cows that have low RFI when fed high corn diets will likely also have low RFI when fed diets high in nonforage fiber sources.

Section: Production Responses To High and Low Starch Dietsmentioning

confidence: 83%

Residual feed intake is repeatable for lactating Holstein dairy cows fed high and low starch diets

Potts

Boerman

Lock

et al. 2015

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“…An additional milk sample was collected at each milking on d 21, 42, and 63 of the study and stored without preservative at −20°C for determination of FA profile. Body weight measurements were taken 3 times per week following the afternoon milking, and BW change was calculated according to Boerman et al (2015b). Body condition was scored weekly by 3 trained investigators on a 5-point scale, in 0.25-unit increments, where 1 = thin and 5 = fat, as described by Wildman et al (1982).…”

Section: Data and Sample Collectionmentioning

confidence: 99%

“…Dried samples were ground with a Wiley mill (1-mm screen; Arthur H. Thomas, Philadelphia, PA). Feed ingredients, orts, and feces were analyzed for NDF, CP, and starch concentration as described by Boerman et al (2015b). Fatty acid concentrations in feed ingredients, orts, and feces were determined as described by Lock et al (2013).…”

Section: Sample Analysismentioning

confidence: 99%

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

Souza

Lock

2018

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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.

“…Glucogenic nutrients are highly important to intermediary metabolism during ruminant lactation because mammary glucose use is high, but direct glucose absorption from the diet is low. Glucogenic diets fed to cows in early and mid-lactation promote energy storage in the body and decrease milk energy content (van Knegsel et al, 2007a,b;Boerman et al, 2015). These shifts in energy partitioning are also observed when glucose or glucogenic precursors are infused along the digestive tract Rigout et al, 2002a).…”

Section: Introductionmentioning

confidence: 99%

Energy and nitrogen partitioning in dairy cows at low or high metabolizable protein levels is affected differently by postrumen glucogenic and lipogenic substrates

Nichols

Dijkstra

Laar

et al. 2019

This study tested the effects of energy from glucogenic (glucose; GG) or lipogenic (palm olein; LG) substrates at low (LMP) and high (HMP) metabolizable protein levels on whole-body energy and N partitioning of dairy cattle. Six rumen-fistulated, second-lactation Holstein-Friesian dairy cows (97 ± 13 d in milk) were randomly assigned to a 6 × 6 Latin square design in which each experimental period consisted of 5 d of continuous abomasal infusion followed by 2 d of rest. A total mixed ration consisting of 42% corn silage, 31% grass silage, and 27% concentrate (dry matter basis) was formulated to meet 100 and 83% of net energy and metabolizable protein requirements, respectively, and was fed at 90% of ad libitum intake by individual cow. Abomasal infusion treatments were saline (LMP-C), isoenergetic infusions (digestible energy basis) of 1,319 g/d of glucose (LMP-GG), 676 g/d of palm olein (LMP-LG; major fatty acid constituents are palmitic, oleic, and linoleic acid), or 844 g/d of essential AA (HMP-C), or isoenergetic infusions of 1,319 g/d of glucose + 844 g/d of essential AA (HMP-GG) or 676 g/d of palm olein + 844 g/d of essential AA (HMP-LG). The experiment was conducted in climate respiration chambers to determine energy and N balance in conjunction with milk production and composition, nutrient digestibility, and plasma constituents. Infusion of GG and LG decreased dry matter intake, but total gross energy intake from the diet plus infusions was not affected by GG or LG. Furthermore, GG or LG did not affect total milk, protein, or lactose yields. Infusing GG or LG at the HMP level did not affect milk production differently than at the LMP level. Infusion of GG stimulated energy retention in body tissue, increased plasma glucose and insulin concentrations, decreased lipogenic metabolites in plasma, and decreased milk fat yield and milk energy output. Nitrogen intake decreased and milk N efficiency increased in response to GG, and N retention was not affected. Infusion of LG tended to increase metabolizable energy intake, increased milk fat yield and milk energy output, increased plasma triacylglycerides and long-chain fatty acid concentrations, and had no effect on energy retention. Infusion of LG decreased N intake but did not affect milk N efficiency or N retention. Compared with the LMP level, the HMP level increased dry matter intake, gross and metabolizable energy intake, and total milk, fat, protein, and lactose yields. Milk energy output increased at the HMP level, and protein level did not affect total energy retention. Heat production increased at the HMP level, but only when GG and LG were infused. The HMP level increased N intake, milk N output, and plasma urea concentration, tended to increase N retention, and decreased milk N efficiency. Regardless of protein level, GG promoted energy retention and improved milk N efficiency, but not through increased milk protein yield. Infusion of LG partitioned extra energy intake into milk and had no effect on milk N efficiency.