Fat and starch as additive risk factors for milk fat depression in dairy diets containing corn dried distillers grains with solubles

Abstract

Two experiments were conducted to evaluate the additive effects of starch and fat as risk factors associated with milk fat depression in dairy diets containing corn dried distillers grains with solubles. In experiment 1, 4 multiparous ruminally cannulated Holstein cows, averaging 114±14 d in milk and 662±52 kg of body weight, were randomly assigned to 4 treatments in a 4×4 Latin square to determine the effect of these risk factors on rumen fermentation and milk fatty acid profile. In each 21-d period, cows were assigned to 1 of 4 dietary treatments: a control diet (CON; ether extract 5.2%, starch 19%); CON with added oil (OL; ether extract 6.4%, starch 18%); CON with added starch (STR; ether extract 5.5%, starch 22%); and CON with added oil and starch (COMBO; ether extract 6.5%, starch 23%). After completion of experiment 1, milk production response was evaluated in a second experiment with a similar approach to diet formulation. Twenty Holstein cows, 12 primiparous and 8 multiparous, averaging 117±17 d in milk and 641±82 kg, were used in replicated 4×4 Latin squares with 21-d periods. Results from experiment 1 showed that ruminal pH was not affected by treatment averaging 5.87±0.08. Molar proportion of propionate in rumen fluid was greatest on the COMBO diet, followed by OL and STR, and lowest for CON. The concentration of trans-10,cis-12 conjugated linoleic acid in milk fat increased with the COMBO diet. Adding oil, starch, or a combination of both resulted in lower concentration and yield of fatty acids<16 carbons. Compared with the control, OL and STR resulted in 13% lower concentration, whereas the COMBO diet resulted in a 27% reduction; similarly yield was reduced by 24% with the OL and STR treatments and 54% with the COMBO diet. In experiment 2, milk yield, milk protein percentage, and milk protein yield were similar across treatments, averaging 26.6±1.01 kg/d, 3.2±0.05%, and 0.84±0.03 kg/d, respectively. Fat-corrected milk was greatest for CON, 26.5±1.12 kg/d; no differences were detected among the remaining treatments, which averaged 23.5±1.12 kg/d. Milk fat percentage was greatest when cows consumed CON, 3.3±0.15%; OL and STR averaged 3.0±0.15% and COMBO resulted in the lowest milk fat percentage, 2.73±0.15%. Milk fat yield was 0.25±0.05 kg/d greater for the CON diet compared with the other 3 treatments, which were similar. These results suggest that fat and starch are additive risk factors that will likely induce milk fat depression in diets containing high inclusion of dried distillers grains with solubles.

Changes in fermentation and animal performance during recovery from classical diet-induced milk fat depression using corn with differing rates of starch degradability

“…Milk 16C FA did not differ by day or treatment throughout the duration of this study. Alterations in de novo and preformed FA are characteristics commonly reported in studies investigating MFD, with de novo FA decreasing during MFD and the preformed FA increasing significantly (Ramirez Ramirez et al, 2015;Rico et al, 2015a). These results suggest that StK d represents a factor that may inhibit full recovery from MFD.…”

“…Similarly, high-starch diets increase ruminal propionate production and flux to the liver, stimulating hepatic oxidation and generation of ATP, which can also reduce DMI (Bradford and Allen, 2005;Albornoz and Allen, 2018). Ramirez Ramirez et al (2015) and Harvatine and Allen (2006a) reported reductions in DMI with high PUFA intake. Harvatine et al (2009b) suggested that under MFD conditions as a result of the reduction in milk energy output, energy can be partitioned toward body reserve replenishment.…”

High rumen degradable starch decreased goat milk fat via trans-10, cis-12 conjugated linoleic acid-mediated downregulation of lipogenesis genes, particularly, INSIG1

“…To provide sufficient energy for high-yielding dairy ruminants, they are typically fed starch-enriched diets. However, starch-enriched diets are known to increase the risk of milk fat depression (MFD) in dairy cows [1][2][3]. MFD is a multifactorial disorder characterized by sustained reduction in milk fat synthesis, which can reduce milk fat production and milk quality, induce potentially adverse effects on animal health and bring about important economic losses [4].…”

Impact of nutrition of food animals on quality of animal products

“…Moreover, feeding of unsaturated fatty acids to ruminants has long been known to induce milk fat depression Ensor et al, 1959;Maynard et al, 1936;Moore et al, 1945;Ramirez Ramirez et al, 2015). Both the 10 and 20% DDGS treatment diets had significantly less SFA, more PUFA, and more unsaturated fatty acids (UFA) ( Table 4).…”

“…Feeds containing high concentrations of unsaturated fatty acids (i.e., corn oil in distillers grains) negatively influences production parameters of lactating dairy cattle through inhibition of ruminal fiber digestion Ensor et al, 1959;Maynard et al, 1936;Moore et al, 1945;Ramirez Ramirez et al, 2015;Zinn et al, 1989) and inhibition of de novo lipogenesis in the mammary gland, particularly through the action of trans-10 cis-12 conjugated linoleic acid . Additionally, diets with a concentration of fat over 5% can negatively influence milk production, regardless of degree of unsaturation (Zinn et al, 1989).…”