The Production of Dual-Purpose Triticale in Arid Regions: Application of Organic and Inorganic Treatments under Water Deficit Conditions

Most of the arid and semi-arid regions, particularly in the Mediterranean area, suffer from the lack of a sufficient quantity of high-quality feed, as well as a low amount of rainfall that is unevenly distributed, resulting in the region being highly vulnerable to drought. A field experiment was carried out at the experimental station of the Faculty of Desert and Environmental Agriculture, Fuka, Matrouh University, Egypt during the winter seasons of 2018/19 and 2019/20 to study the performance of triticale (X Triticosecale Wittmack), grown under water deficit conditions, in terms of productivity and quality. The study investigated the influence of five levels of potassium fertilization (PF; 0, 43.2, 86.4, 129.6, and 172.8 kg ha−1) and ascorbic acid (AA; 0, 25, 50, 75, and 100 mg L−1) that was applied to the triticale grains before sowing and humic acid (HA; 0, 2.4, 4.8, 7.2, and 9.6 kg ha−1) that was applied as powder to the soil 21 days after sowing followed by sprinkler irrigation on triticale forage and grain production when forage was removed at variable ages at cutting (AC), determined as days after sowing (AC; 40, 65, 90, 115, and 140 DAS) on forage yield and nutritive value, in addition to the final grain yield of triticale. The experimental design was a central composite design with one replicate. Results indicated that the PF*AC interaction was significant, and it gave values of 84.78 and 238.00 g kg−1 for crude protein (CP) and degraded neutral detergent fiber (DNDF). In addition, the interaction between AA and AC was significant for CP, acid detergent fiber (ADF), 100-grain weight (100 GW), number of spikes m−2 (NSM−2), and plant height (PH). Moreover, the AC*HA interaction was significant with values of 175.17 and 247.00 g kg−1 for CP and DNDF, respectively, and 0.55 t ha−1 for grain yield (GY). Age at cutting exerted the strongest effect on the studied characteristics. It was observed that the contents of neutral detergent fiber (NDF), ADF, acid detergent lignin (ADL), and non-fiber carbohydrates (NFC) in the triticale forage significantly increased when the crop was cut at an advanced age, unlike CP, DNDF, GY, NSM−2, 100 GW, and PH that decreased with advanced AC. The highest values of 271.00, 256.00, and 268.00 g kg−1 for DNDF were obtained with higher levels of either PF, AA, or HA, respectively. However, the highest value of GY (0.97 t ha−1) was obtained with higher levels of PF*HA averaged over the two seasons. The interaction between AA*HA resulted in 393.39, 311.00, 27.13 g kg−1, and 0.94 t ha−1, for NDF, DNDF, ADL, and GY, respectively. The highest significant NDF (413.11 g kg−1) and DNDF (307.50 g ka−1) values were obtained with the application of high levels of either AA or HA. In the dual-purpose production system, it is recommended to cut the triticale crop at 65 DAS to achieve the optimum balance between forage yield and quality on the one hand, and final grain yield on the other hand. In the arid regions, application of PF, AA, and HA could help in reducing the damage caused by water deficit.

Comparison of microbial diversity in rumen and small intestine of Xinong Saanen dairy goats using 16S rRNA gene high-throughput sequencing

Context Gastrointestinal microorganisms play an important role in ruminant digestion and metabolism, immune regulation and disease prevention and control. Different parts of the digestive tract have different functions and microbial community structures. Aims This study aims to explore the microbial diversity in the rumen and the small intestine of Xinong Saanen dairy goats. Methods Rumen fluid and jejunum fluid from three Xinong Saanen dairy bucks with the average slaughter weight of 33.93 ± 0.68 kg were collected and analysed for microbial diversity, by using 16S rRNA gene high-throughput sequencing. Key results In total, 1118 operational taxonomic units (OTUs) were identified, with 1020 OTUs and 649 OTUs being clustered to rumen and jejunum samples respectively. Alpha-diversity indices were significantly (P < 0.05) different between rumen and jejunum, as indicated by the fact that the rumen microbial community diversity, richness and uniformity/evenness were higher than those of jejunum. At the phylum level, the dominant phyla in the rumen were Bacteroidetes (66.7%) and Firmicutes (25.1%), accounting for 91.8% of the rumen microorganisms. The dominant phylum in the jejunum was Firmicutes, accounting for 73.0% of the jejunum microorganisms. At the genus level, the dominant bacteria in the rumen were Prevotella_1, norank_f_Bacteroidales_BS11_gut_group, Rikenellaceae_RC9_gut_group, Christensenellaceae_R-7_group and Family_XIII_AD3011_group, whereas the dominant bacteria in the jejunum were Omboutsia, Aeriscardovia, Intestinibacter, unclassified_f_Peptostreptococcaceae and unclassified_f_Bifidobacteriaceae. Clusters of Orthologous Groups (COG) and Kyoto Encyclopedia of Genes and Genomes (KEGG) results showed that the major functions of microorganisms in the rumen and jejunum were carbohydrate metabolism, amino acid metabolism, nucleotide metabolism, membrane transport and translation. Interestingly, fructose and mannose metabolism and peptidoglycan biosynthesis were abundant in the rumen, while homologous recombination and nucleotide excision repair were abundant in the jejunum. Conclusions Our study clarified the differences in microbial diversity and community structure between the rumen and the jejunum in Xinong Saanen dairy goats. Prevotella was the most predominant genus in the rumen, compared with Romboutsia, Bifidobacterium as well as Peptostreptococcaceae genera, which were the predominant genera in the jejunum. Implications In combination with the functional prediction of microorganisms and the metabolic characteristics of different parts of the digestive tract in ruminants, our findings provided information for further exploring the relationship among genes, species and functions of microorganisms and their hosts’ nutritional and physiological functions.

Canola Meal versus Soybean Meal as Protein Supplements in the Diets of Lactating Dairy Cows Affects the Greenhouse Gas Intensity of Milk

Soybean meal (SBM) and canola meal (CM) are protein supplements used in lactating dairy cow diets and, recently, an enteric methane-mitigating effect (i.e., lower Ym value) was reported for CM. Before recommending CM as a greenhouse gas (GHG) mitigation strategy, it is necessary to examine the net impact on total GHG emissions from milk production. The objective was to determine whether using CM rather than SBM in lactating dairy cow diets decreases GHG per kilogram of fat and protein corrected milk (FPCM), and whether the decrease depends upon where the meals are produced. Cradle to farm-gate life cycle assessments were conducted for a simulated dairy farm in eastern (Quebec) and western (Alberta) Canada. Scenarios examined the source of protein meal, location where meals were produced, and the methane-mitigating effect of CM. The Holos model was used to estimate GHG emissions from animals, manure, crop production, imported feeds, and energy use. GHG intensities (CO2e/kg FPCM) were 0.85-1.02 in the east and 1.07-1.11 in the west for the various scenarios, with enteric methane comprising 34 to 40% of total emissions. CM produced in western Canada with a low up-stream emission factor and low Ym value reduced CO2e/kg FPCM by 3% (western farm) to 6.6% (eastern farm) compared with SBM. We conclude that using CM rather than SBM in the diet of lactating dairy cows can be a GHG mitigation strategy depending upon where it is produced and whether it decreases enteric methane emissions.

Effects of a high-protein corn product compared with soy and canola protein sources on nutrient digestibility and production responses in mid-lactation dairy cows

An experiment was conducted to assess the effects of a novel and proprietary high-protein corn product [56% crude protein (CP)] relative to other common sources of protein on the lactation performance of dairy cows. Twenty-four Holstein cows (620 ± 47.7 kg of body weight, 111 ± 34 d in milk, 2.28 ± 0.46 lactations; mean ± standard deviation) were randomly assigned to treatment sequence in a replicated 4 × 4 Latin square design balanced for carryover effects. Cows were individually fed 1 of 4 diets with a different protein concentrate source during each 28-d period, including soybean meal (SBM), high-protein corn product (HPCP), soybean meal with rumen-bypass soy protein (SBMBP), and canola meal with rumen-bypass soy protein (CANBP). Diets were formulated for equal concentrations of CP and balanced to meet predicted lysine and methionine requirements. The SBM diet was formulated to provide 5.7% rumen-undegradable protein (RUP), whereas SBMBP and CANBP diets were formulated for 6.8% RUP to match HPCP. Data were analyzed using mixed models with the fixed effects of treatment, period, square, the interactions of treatment and period and of treatment and square, and the random effect of cow. The CANBP diet increased dry matter intake (DMI) compared with SBM and HPCP. Treatment affected milk yield, as SBMBP and CANBP increased yield compared with SBM, but HPCP decreased milk yield compared with all treatments. The HPCP diet reduced CP intake as a percent of total DMI and increased the CP content of orts, indicative of selection against HPCP. The HPCP diet also decreased apparent total-tract and CP digestibility, leading to less urine nitrogen excretion and greater fecal nitrogen output. The SBMBP and CANBP diets performed similarly in nearly every variable measured, except that SBMBP increased milk urea nitrogen. In conclusion, the HPCP diet reduced yield of milk and milk components, likely because of reduced apparent total-tract dry matter and CP digestibility.

Effects of processing methods (rolling vs. pelleting vs. steam-flaking) of cool-season adapted oats on dairy cattle production performance and metabolic characteristics compared with barley

Several processing techniques can be used to slow the degradation rate in the rumen and thus provide more bypass crude protein (CP) and starch to the small intestine. The aim of this study was to evaluate the effects of processing methods on cool-season adapted oat grain compared with dry-rolled barley grain, when fed as total mixed ration (TMR) for lactating dairy cows. Eight lactating Holstein cows were used in a replicated 4 × 4 Latin square design with 21-d periods and fed TMR with 1 of 4 treatments: dry-rolled oats, steam-flaked oats, pelleted oats, or dry-rolled barley. Dry matter intake (DMI) ranged from 28.19 to 31.61 kg/d and was lower for rolled oats compared with pelleted oats. Despite the nutrient intake being higher for cows fed pelleted oats, those fed rolled oats had the highest milk production and milk fat percentage (49.23 kg/d and 4%, respectively). Ruminal fermentation characteristics were similar across treatments, with only significant differences in concentrations of acetate (lowest for pelleted oats) and total short-chain fatty acids (highest value for rolled barley) and a lower pH for flaked oats at the 9-h and 12-h points. Dietary treatments did not affect total-tract digestibility of dry matter, organic matter, or CP; digestibility of starch was the lowest for rolled barley (89.04%). Measured blood metabolites, urea, glucose, and β-hydroxybutyrate, were not affected by dietary treatment. Purine derivatives and microbial N supply were also unaffected by dietary treatments. Cows fed flaked oat-based TMR showed the lowest N excretion in milk; however, the lack of difference between diets with regard to urinary N and fecal N excretion resulted in no significant changes in N balance between diets. Therefore, rolled oats allow cows to have higher milk production with lower DMI compared with all other treatments in this study.

Effect of substituting soybean meal and canola cake with dried distillers grains with solubles at 2 dietary crude protein levels on feed intake, milk production, and milk quality in dairy cows

Dried distillers grain with solubles (DDGS) is an alternative source of feed protein for dairy cows. Previous studies found that DDGS, based on grains other than corn, can substitute for soybean meal and canola cake as a dietary protein source without reducing milk production or quality. As societal concerns exist, and in many areas strict regulation, regarding nitrogen excretion from dairy cows, the dairy industry has focused on reducing dietary protein level and nitrogen excretion. In the present study, we investigated the use of DDGS as a protein source, at a marginally low dietary crude protein (CP) levels, in a grass-clover and corn silage-based ration. The experiment involved 24 Holstein cows and 2 protein sources (DDGS or soybean-canola mixture) fed at 2 levels of CP (14 or 16%) in a 4 × 4 Latin square design. The aim of this study was to evaluate the effect of both protein source and protein level on feed intake, milk yield, and milk quality. The results indicated that feed intake, milk yield, and protein in milk increased when the protein level in the ration was 16% CP compared with 14%. We found no effect of substituting the soybean-canola mixture with DDGS. Moreover, no sensory problems were observed when comparing fresh milk with stored milk, and milk taste was unaffected by DDGS. Milk from cows fed DDGS had a slightly higher content of linoleic acid and conjugated linoleic acid (CLA 9-11), and lower content of C11 to C17 fatty acids than cows fed diets with the soybean-canola mixture. Cows fed the diets with 16% CP produced milk with higher oleic acids and lower palmitic acid content than cows fed 14% CP diets. To conclude, DDGS can substitute for a soybean-canola mixture without affecting feed intake, milk yield and quality, or sensory quality. Under the conditions of this experiment, feeding 16% CP compared with 14% CP in the ration can increase feed intake and milk production.

Effect of substituting soybean meal and canola cake with grain-based dried distillers grains with solubles as a protein source on feed intake, milk production, and milk quality in dairy cows

The growth of the bioethanol industry is leading to an increase in the production of coproducts such as dried distillers grains with solubles (DDGS). Both corn-based DDGS and grain-based DDGS (gDDGS; defined as originating from grain sources such as barley, wheat, triticale, or a mix, excluding corn) appear to be relevant sources of feed and protein for dairy cows. To date, most of the studies investigating DDGS have been performed with corn-based DDGS. The objectives of this study were to determine the effects of the proportion of gDDGS in the diet on feed intake, milk production, and milk quality. The present experiment involved 48 Holstein cows in a replicated 3 × 3 Latin square design with 3 grass-based dietary treatments consisting of 4, 13.5, and 23% gDDGS on a dry matter (DM) basis (L, M, and H, respectively) as a replacement for a concentrate mix. The concentrate mix consisted of soybean meal, canola cake, and beet pulp. Dry matter intake and energy-corrected milk yield were not affected by the proportion of gDDGS in the diet. Daily milk yield decreased with the H diet compared with the L and M diets. The percentage of fat in milk was higher when cows were fed the H diet compared with the L and M diets, whereas milk fat yield was not affected by dietary treatment. The M diet had a higher percentage of protein in milk compared with the L and H diets. Milk protein yield was similar for the L and M diets; however, it decreased for the H diet. Milk taste was not affected by the proportion of gDDGS in the diet or when milk was stored for 7 d. Linoleic acid and conjugated linoleic acid cis-9,trans-11 in milk increased with increasing proportion of gDDGS. To conclude, gDDGS can replace soybean meal and canola cake as a protein source in the diet of dairy cows. Up to 13.5% of the diet may consist of gDDGS without negatively affecting milk production, milk quality, or milk taste. When gDDGS represents 23% of dietary DM, milk production is reduced by 1.6 kg/d, whereas energy-corrected milk production is numerically reduced by 1 kg.

Rumen Degradability and Small Intestinal Digestibility of the Amino Acids in Four Protein Supplements

The supplementation of livestock feed with animal protein is a present cause for public concern, and plant protein shortages have become increasingly prominent in China. This conflict may be resolved by fully utilizing currently available sources of plant protein. We estimated the rumen degradability and the small intestinal digestibility of the amino acids (AA) in rapeseed meal (RSM), soybean meal (SBM), sunflower seed meal (SFM) and sesame meal (SSM) using the mobile nylon bag method to determine the absorbable AA content of these protein supplements as a guide towards dietary formulations for the dairy industry. Overall, this study aimed to utilize protein supplements effectively to guide dietary formulations to increase milk yield and save plant protein resources. To this end, we studied four cows with a permanent rumen fistula and duodenal T-shape fistula in a 4×4 Latin square experimental design. The results showed that the total small intestine absorbable amino acids and small intestine absorbable essential amino acids were higher in the SBM (26.34% and 13.11% dry matter [DM], respectively) than in the SFM (13.97% and 6.89% DM, respectively). The small intestine absorbable Lys contents of the SFM, SSM, RSM and SBM were 0.86%, 0.88%, 1.43%, and 2.12% (DM basis), respectively, and the absorbable Met contents of these meals were 0.28%, 1.03%, 0.52%, and 0.47% (DM basis), respectively. Among the examined food sources, the milk protein score of the SBM (0.181) was highest followed by those of the RSM (0.136), SSM (0.108) and SFM (0.106). The absorbable amino acid contents of the protein supplements accurately reflected protein availability, which is an important indicator of the balance of feed formulation. Therefore, a database detailing the absorbable AA should be established.

Invited Review: Ethanol co-products for dairy cows: there goes our starch … now what?

Paz, H. A., Castillo-Lopez, E., Ramirez-Ramirez, H. A., Christensen, D. A., Klopfenstein, T. J. and Kononoff, P. J. 2013. Invited Review: Ethanol co-products for dairy cows: there goes our starch … now what? Can. J. Anim. Sci. 93: 407–425. The rise of the grain-ethanol industry has resulted in a dramatic increase in the availability of feed co-products namely, distillers’ grains with solubles (DG). The cost of feeds that have traditionally been used for energy continues to increase and there is a need to understand the potential impact of replacing these feeds with DG on milk yield and composition. Using the Dairy National Research Council (2001) model and data from a total of 25 published studies (81 observations), we used a meta-analytical procedure to evaluate the impact of feeding corn milling co-products on lactating dairy cows. Based on our model, the inclusion of DG did not affect dry matter intake (P=0.35) but a trend for an increase in milk yield was observed (P=0. 10). Additionally, the percentages of milk fat and protein in the milk were not affected (P=0.24 and 0.25, respectively). The modeled daily rumen outflow of Lys in grams was significantly (P<0.01) reduced and Met was not affected (P=0.79) when DG were included. The error associated with net energy of lactation allowable milk averaged 5.0±1.0 kg d−1and was not affected by DG (P=0.79) but the error associated with metabolizable protein allowable milk tended (P=0.10) to be higher for cows consuming DG by 1.4±1.2 kg d−1.

Effect of substitution of soybean meal by canola meal or distillers grains in dairy rations on amino acid and glucose availability

Canola meal (CM) or by-products of ethanol production (dried distillers grain, DDG) may offer an economical alternative to soybean meal (SBM) in North American dairy rations. These protein supplements can effectively replace SBM and, in 2 recent meta-analyses, CM had a positive effect on milk and milk protein yields compared with SBM. The objective of this study was to determine if the positive responses observed with inclusion of CM in dairy rations could be explained by an increased availability of His, Lys, Met, or glucose. Eight Holstein dairy cows were used in a replicated 4×4 Latin square with 14-d periods. Cows were fed isonitrogenous (17.2% crude protein) and isoenergetic (1.56 Mcal/kg of net energy of lactation) diets formulated to slightly exceed nutrient requirements. Diets contained 38% grass hay and 62% corn-based concentrate including SBM, CM, corn high-protein DDG (HPDDG), or wheat DDG plus solubles (WDDGS) as the single protein supplement. The effect of protein supplements on availability of His, Lys, Met, and glucose was estimated using variations in the whole-body (WB) flux of these nutrients, determined by isotopic dilution. As planned, dry matter intake and milk and milk protein yields were not affected by treatments and averaged 23.7, 31.4, and 1.14 kg/d, respectively. Lactose yield did not differ among diets although milk lactose content tended to be lower with CM and WDDGS diets than with SBM and HPDDG diets. Lysine availability was affected by treatments: the highest WB irreversible loss rate (ILR) was observed for the CM diet (371 g/d) and the lowest for HPDDG diet (290 g/d); values for SBM and WDDGS were intermediate (330 and 316 g/d, respectively). Availability of His and Met did not vary among diets and WB ILR averaged, respectively, 129 and 124 g/d; the CM diet, however, had numerically the highest His and Met ILR. Plasma concentrations of most of the essential AA were higher with the CM diet and lower with the HPDDG diet, the exception being Leu for which the concentration was highest for the HPDDG diet. Glucose WB rate of appearance was altered by diet, with the highest mean observed for SBM (3,036 g/d) and the lowest for CM (2,795 g/d); the 2 diets with the lowest WB glucose rate of appearance (CM and WDDGS) also had the lowest dietary starch concentration. Overall, this study suggested that positive responses in milk and milk protein yields observed with inclusion of CM in dairy rations could be linked to a greater supply of metabolizable protein, including some essential AA, especially His, Lys, and Met, as glucose availability was certainly not increased in cows fed the CM diet.

Ruminal degradability of dry matter, crude protein, and amino acids in soybean meal, canola meal, corn, and wheat dried distillers grains

Different protein sources, such as canola meal (CM) or dried distillers grains (DDG), are currently used in dairy rations to replace soybean meal (SBM). However, little data exists comparing their rumen degradation in a single study. Therefore, the objective of this study was to compare the ruminal degradation of dry matter (DM), crude protein (CP), and AA of SBM, CM, high-protein corn DDG (HPDDG), and wheat DDG plus solubles (WDDGS). In situ studies were conducted with 4 rumen-fistulated lactating Holstein cows fed a diet containing 38% grass hay and 62% corn-based concentrate. Each protein source was incubated in the rumen of each cow in nylon bags for 0, 2, 4, 8, 16, 24, and 48 h to determine DM and CP rumen degradation kinetics, whereas additional bags were also incubated for 16 h to evaluate AA ruminal disappearance. Rumen DM and CP degradability was calculated from rumen-undegraded residues corrected or not for small particle loss. Data were fitted to an exponential model to estimate degradation parameters and effective degradability (ED) was calculated with a passage rate of 0.074 h(-1). The WDDGS and SBM had higher uncorrected ED (DM=75.0 and 72.6%; CP=84.8 and 66.0%, respectively) than CM and HPDDG (DM=57.2 and 55.5%; CP=59.3 and 48.2%, respectively), due to higher soluble fraction in WDDGS and a combination of higher potentially degradable fraction and rate of degradation in SBM. Correction for small particle loss from bags, higher for WDDGS than for the other protein sources, decreased estimated ED but did not alter feed ranking. The ruminal disappearance of AA after 16 h of incubation reflected the overall pattern of CP degradation between protein supplements, but the ruminal disappearance of individual AA differed between protein supplements. Overall, these results indicate that, in the current study, (1) SBM and WDDGS were more degradable in the rumen than CM and HPDDG, and (2) that small particle loss correction is relevant but does not alter this ranking.

Effects of dietary carbohydrates on rumen epithelial metabolism of nonlactating heifers

Ruminal wall metabolism was studied in nonlactating heifers by altering the carbohydrate (CHO) digestion site between rumen and intestine. The CHO digestion site was estimated from in situ and total-tract digestibility of control (CONT) diets and diets supplemented with corn (CRN), barley (BARL), or soy hulls (SOYH). Ruminal epithelial metabolism regulating gene expression, morphology, and nutrient delivery was assessed from a combination of rumen volatile fatty acid (VFA) concentration, biopsies for papilla morphology, and expression of putative metabolic regulatory genes encoding enzymes that facilitate VFA utilization. Digestible dry matter and CHO intake were 25 and 45% higher, respectively, in the supplemented diets than in CONT diets. Fiber supplementation increased the intestinal and decreased ruminal CHO digestion. Ruminal nonfiber CHO digestibility was 10% lower in CRN than with the high rumen-degradable supplement. The CONT heifers had lowest total ruminal VFA and highest acetate concentration relative to the other treatments. Total VFA concentration in BARL and CRN diets tended to be higher than in SOYH. The SOYH diet tended to reduce papilla dimension relative to CRN and BARL. The CRN diet tended to increase papilla surface area relative to BARL and SOYH. Gene expression of propionyl-coenzyme A carboxylase was higher in CRN and BARL than in SOYH diets, and tended to be higher in CRN than in BARL and SOYH diets. Lactate dehydrogenase and butyryl coenzyme A synthase gene transcripts tended to be higher in CONT than in the supplemented treatments. Thus, rumen epithelial expression of genes involved in VFA metabolism and ruminal wall-structure development are influenced by other regulatory mechanism that is not directly affected by local signals. The in situ methods used are a useful tool for differentiating ruminal from extraruminal nutrient supply.

Molecular structure and metabolic characteristics of the proteins and energy in triticale grains and dried distillers grains with solubles for dairy cattle

To our knowledge, there is no research on the molecular structure of triticale grain in comparison with other types of cereal grains and metabolic characteristics of the protein and energy in this grain and its coproducts, called dried distillers grains with solubles (DDGS), for dairy cattle. The objective of this study was to identify differences in molecular structures of proteins among grains and their DDGS using a molecular spectroscopy technique, namely, DRIFT, and to determine the nutrient profile and supply to dairy cattle. The protein molecular structure studies showed a difference (P < 0.01) in the amide I to amide II ratio and the α-helix to β-sheet ratio between grains and their DDGS. The energy content was similar for triticale grain and DDGS. There were differences in the protein and carbohydrate subfractions (P < 0.05) and the ruminal degradability of DM, CP, and NDF (P < 0.01) between triticale grain and DDGS. Triticale grain and DDGS had similar intestinal digestibility of rumen undegraded CP. However, triticale DDGS had higher (P < 0.01) predicted total metabolizable protein and degraded protein balance than triticale, indicating that triticale DDGS is a superior protein source for dairy cattle as compared with triticale grain. Bioethanol processing induced changes in the protein molecular structure.

Rumen fermentation, milk production and conjugated linoleic acid in the milk of cows fed high fiber diets added with dried distillers grains with solubles

The effects of corn dried distillers grains with solubles (DDGS) feeding on rumen fermentation and milk production in cows were evaluated using diets high in neutral detergent fiber (NDF, 45.9-46.6%). The control diet (Control) consisted mainly of hay, corn silage and concentrates. In the experimental diets, the concentrates were replaced with DDGS as 10% dry matter (DM) (10%DDGS) and 20% DM (20%DDGS). Eight cows were used for each 14-day treatment period. Effect of DDGS feeding on DM intake was not significant. Ruminal volatile fatty acids and ammonia-N at 5 h after feeding of 20%DDGS were decreased compared to Control, whereas protozoal count at 2 h after feeding of 20%DDGS was higher than that of 10%DDGS. Milk yield of cows fed DDGS diets was greater than that of Control, although percentages of milk protein and solids-not-fat were decreased by DDGS diets. The proportions of C10:0, C12:0, C14:0 and C16:0 in the milk fat decreased, and those of C18:0, C18:1, C18:2 and cis-9, trans-11 conjugated linoleic acid (CLA) increased markedly with elevated DDGS. Increase in trans-11 C18:1 was observed in the rumen fluid at 5 h after feeding. These findings suggest that DDGS feeding enhanced milk yield, as well as CLA synthesis under a high dietary NDF condition.