Lactational response to soybean meal, heated soybean meal, and extruded soybeans with ruminally protected methionine

Effects of dietary extrusion on rumen fermentation, nutrient digestibility, performance and milk composition of dairy cattle: a meta-analysis

OBJECTIVE

The present study aimed to evaluate the effects of extruded and unextruded feeding on the performance, milk composition, digestibility and ruminal fermentation of dairy cows through a meta-analysis.

METHODS

The database was compiled from 53 studies in Scopus and PubMed. The data were analyzed using a random effects model in OpenMEE software. Extruded feed was grouped as the experiment group while and the others as control group. The bias of publication in the main parameter of dairy performance was evaluated by a funnel plot.

RESULTS

The result showed that extruded feed enhanced the milk yield, dry matter and crude protein digestibility, butyrate and valerate acid production (p<0.05). Meanwhile, the extruded feed significantly decreased the milk fat and protein concentration (p<0.05). Also, the iso-butyrate and iso-valerate in unextruded feeding was significantly higher than the extruded feed (p<0.05).

CONCLUSION

It was concluded from the meta-analysis that extruded feed effectively improved the milk production and milk lactose concentration, dry matter and protein digestibility, but not the milk fat and protein concentration.

The effects of rumen-protected tryptophan (RPT) on production performance and relevant hormones of dairy cows

Tryptophan is an essential amino acid that cannot be synthesized in mammals. Therefore, the dietary supply of tryptophan is critical for the health and production performance (e.g., milk) of mammals. In the present study, 36 lactating Holstein cows were used, of which 24 cows were in the rumen-protected tryptophan (RPT) feeding groups with different doses at 14 g/d and 28 g/d, respectively and 12 cows were in the control group. This approach could avoid dietary tryptophan being degraded by the rumen microorganisms and improve its bioavailability for cows. The results showed that RPT increased milk protein percentage, milk protein yield, milk solid non-fat (SNF), and milk yield. In response to RPT treatment, the levels of melatonin (MT), prolactin (PRL), and insulin-like growth factor-1 (IGF-1) were significantly increased in the serum of cows compared to the controls. RPT feeding improved nutrient utilization efficiency and lactation performance of dairy cows, which enhanced the quality of milk.

Nutrigenomic Interventions to Address Metabolic Stress and Related Disorders in Transition Cows

For dairy cattle, the period involving a shift from late pregnancy to early lactation termed transition or periparturient is an excruciating phase. Health-related disorders are likely to happen in this time frame. Timely postpartum and metabolic adjustments to this new physical state demands correct management strategies to fulfill the cow's needs for a successful transition to this phase. Among the management strategies, one of the most researched methods for managing transition-related stress is nutritional supplementation. Dietary components directly or indirectly affect the expression of various genes that are believed to be involved in various stress-related responses during this phase. Nutrigenomics, an interdisciplinary approach that combines nutritional science with omics technologies, opens new avenues for studying the genome's complicated interactions with food. This revolutionary technique emphasizes the importance of food-gene interactions on various physiological and metabolic mechanisms. In animal sciences, nutrigenomics aims to promote the welfare of livestock animals and enhance their commercially important qualities through nutritional interventions. To this end, an increasing volume of research shows that nutritional supplementation can be effectively used to manage the metabolic stress dairy cows undergo during the transition period. These nutritional supplements, including polyunsaturated fatty acids, vitamins, dietary amino acids, and phytochemicals, have been shown to modulate energy homeostasis through different pathways, leading to addressing metabolic issues in transition cows.

Effect of heat treatment and heat treatment in combination with lignosulfonate on in situ rumen degradability of canola cake crude protein, lysine, and methionine

The aim of this study was to determine the effect of heat treatment alone or in combination with the addition of lignosulfonate (LSO3) on canola cake protein, lysine, and methionine degradation in the rumen. Cold-pressed canola cake was left untreated, heated at 90, 110, 130, or 150 °C, or processed with 5% of LSO3 (in dry matter) and then heated. Effective rumen degradability of crude protein (CP), lysine, and methionine was less for treated than untreated canola cake (P < 0.05) and decreased with increased temperature of heating, but particularly when canola cake was heated at 150 °C (quadratic, P < 0.01). In general, effective rumen degradability of CP, lysine, and methionine was less for canola cake heated at 130 °C in combination with LSO3 compared with canola cake heat treated only (quadratic × LSO3 interaction, P ≤ 0.07). Results of this study indicate that high temperature heating (130 °C or greater for 60 min) may be necessary to protect canola cake protein from degradation in the rumen, and the combination of heat treatment and LSO3 may be more effective in protecting canola cake protein, lysine, and methionine from degradation in the rumen than the use of heat treatment only.

Production effects of feeding extruded soybean meal to early-lactation dairy cows

The objective of this experiment was to evaluate productive and reproductive effects of replacing solvent-extracted soybean meal (SSBM) with extruded soybean meal (ESBM) in a total mixed ration for early-lactation dairy cows. Thirty-four Holstein cows (12 primiparous and 22 multiparous) were used in a randomized complete block design experiment with 17 cows per treatment. Feeding was ad libitum for 5 to 10% refusals. A fresh-cow diet was fed the first 21 d in milk followed by a lactation diet from 22 to 60 d in milk. Milk and dry matter intake data were collected throughout the experiment, and samples were collected for blood chemistry and amino acid profile, nutrient digestibility, nitrogen utilization, and enteric methane emission using the GreenFeed system (C-Lock Inc., Rapid City, SD). Dry matter intake, milk yield, and feed efficiency were not different between SSBM and ESBM. Energy-corrected milk yield and efficiency were also not different between diets. Diet had no effect on milk composition, except that milk true protein yield was decreased by ESBM. Enteric methane emission, yield, and intensity were not different between SSBM and ESBM. Because of its greater fat content, ESBM triggered expected changes in milk fatty acid (FA) profile: decreased sum of C16, saturated, and odd- and branched-chain FA and increased sum of preformed FA, polyunsaturated, and trans FA. The ESBM diet increased or tended to increase some essential amino acids in plasma. In this study, ESBM did not affect dry matter intake and did not improve lactational performance or onset of ovarian function in early-lactation dairy cows, and it decreased milk protein yield, possibly due to greater unsaturated FA intake compared with SSBM.

Effects of rumen-protected methionine on milk production in early lactation dairy cattle fed with a diet containing 14.5% crude protein

We evaluated the influence on milk production of feeding early lactation cows a diet that included 14.5% crude protein (CP) and that did not meet methionine (Met) requirements or that met them by supplying rumen‐protected Met (RPMet). Thirty‐nine multiparous Holstein cows were allocated into two groups. For 15 weeks after calving, each group was fed one of the two total mixed rations, Control (n = 20) or Treatment (n = 19). The Treatment group received added RPMet at 0.034% (8 g/day) of the Control diet on dry matter basis. The adequacies of Met for the Control and Treatment groups were 96% and 106%, respectively, and for other amino acids, >110%. The CP level (14.5%) was 1 percentage point lower than that recommended by the Japanese Feeding Standard (2006). No between‐group differences were found in milk yield (40 kg/day), milk composition, plasma profile, rumen fermentation, nitrogen balance, or cow health. Met intake and the amount of rumen‐undegradable feed Met were higher in the Treatment group (p < 0.05). Microbial Met and total metabolizable Met did not differ between groups. Supplying RPMet in a 14.5% CP diet during early lactation did not dramatically affect milk production, because the amount of total metabolizable Met was unchanged.

A 100-Year Review: Metabolic modifiers in dairy cattle nutrition

The first issue of the Journal of Dairy Science in 1917 opened with the text of the speech by Raymond A. Pearson, president of the Iowa State College of Agriculture, at the dedication of the new dairy building at the University of Nebraska (J. Dairy Sci. 1:4-18, 1917). Fittingly, this was the birth of a new research facility and more importantly, the beginning of a new journal devoted to the sciences of milk production and manufacture of products from milk. Metabolic modifiers of dairy cow metabolism enhance, change, or interfere with normal metabolic processes in the ruminant digestive tract or alter postabsorption partitioning of nutrients among body tissues. Papers on metabolic modifiers became more frequent in the journal around 1950. Dairy farming changed radically between 1955 and 1965. Changes in housing and feeding moved more cows outside, and cows and heifers in all stages of lactation, including the dry period, were fed as a single group. Rations became wetter with the shift to corn silage as the major forage in many rations. Liberal grain feeding met the requirements of high-producing cows and increased production per cow but introduced new challenges; for example, managing and feeding cows as a group. These changes led to the introduction of new strategies that identified and expanded the use of metabolic modifiers. Research was directed at characterizing the new problems for the dairy cow created by group feeding. Metabolic modifiers went beyond feeding the cow and included environmental and housing factors and additives to reduce the incidence and severity of many new conditions and pathologies. New collaborations began among dairy cattle specialties that broadened our understanding of the workings of the cow. The Journal of Dairy Science then and now plays an enormously important role in dissemination of the findings of dairy scientists worldwide that address existing and new technologies.

Inclusion of various amounts of steam-flaked soybeans in lactating dairy cattle diets

Whereas most soybean feedstuffs have been extensively investigated for use in ruminant diets, a lack of information exists regarding steam-flaked soybeans (SFSB). This research evaluated various inclusion rates of SFSB in diets for lactating dairy cattle. Twelve multiparous Holstein cows (103 ± 39 d in milk) were used in a 4 × 4 Latin square experiment consisting of 28-d periods, 14 d for diet transitioning followed by a 14-d sampling period. Treatments were inclusion of SFSB at 0, 5, 10, and 15% of dietary dry matter (DM), replacing a mixture of soybean meal, soy hulls, calcium salts of fatty acids, and choice white grease. Animals were fed lactating dairy cow diets formulated to be isonitrogenous and isoenergetic, containing 60% of DM as forage and 40% of DM as concentrate. Dry matter intake (mean = 28.8 kg/d), milk production (42.2 kg/d), milk fat percentage (3.52%), and feed efficiency (1.43 kg of energy-corrected milk/kg of DM intake) were similar across all treatments. Milk protein (2.98%) and lactose (4.87%) were also unaffected by the amount of SFSB in the diet. Milk urea nitrogen concentration decreased linearly as the amount of SFSB in the diet increased. Unlike some other soybean supplements, feeding SFSB did not increase trans-11 C18:1 or cis-9,trans-11 conjugated linoleic acid, but instead resulted in increased cis-9,cis-12 C18:2 and α-C18:3. Body weights (752 kg) and body condition scores (3.17) were similar with all diets. This research demonstrated that SFSB can be substituted for soybean meal and commercial fat sources while maintaining milk and milk component production and decrease milk urea nitrogen concentration.

In vitro and Lactation Responses in Mid-lactating Dairy Cows Fed Protected Amino Acids and Fat

The objective of this study was to evaluate the effect of ruminally protected amino acids (RPAAs) and ruminally protected fat (RPF) supplementation on ruminal fermentation characteristics (in vitro) and milk yield and milk composition (in vivo). Fourteen mid-lactating Holstein dairy cows (mean weight 653±62.59 kg) were divided into two groups according to mean milk yield and number of days of postpartum. The cows were then fed a basal diet during adaptation (2 wk) and experimental diets during the treatment period (6 wk). Dietary treatments were i) a basal diet (control) and ii) basal diet containing 50 g of RPAAs (lysine and methionine, 3:1 ratio) and 50 g of RPF. In rumen fermentation trail (in vitro), RPAAs and RPF supplementation had no influence on the ruminal pH, dry matter digestibility, total volatile fatty acid production and ammonia-N concentration. In feeding trial (in vivo), milk yield (p<0.001), 4% fat corrected milk (p<0.05), milk fat (p<0.05), milk protein (p<0.001), and milk urea nitrogen (p<0.05) were greater in cows fed RPAAs and RPF than the corresponding values in the control group. With an index against as 0%, the rates of decrease in milk yield and milk protein were lower in RPAAs and RPF treated diet than those of basal diet group (p<0.05). In conclusion, diet supplemented with RPAAs and RPF can improve milk yield and milk composition without negatively affecting ruminal functions in Holstein dairy cows at mid-lactating.

Availability to lactating dairy cows of methionine added to soy lecithins and mixed with a mechanically extracted soybean meal

We evaluated a product containing methionine mixed with soy lecithins and added to a mechanically extracted soybean meal (meSBM-Met). Lactational responses of cows, plasma methionine concentrations, and in vitro degradation of methionine were measured. Twenty-five Holstein cows were used in a replicated 5 × 5 Latin square design and fed a diet designed to be deficient in methionine or the same diet supplemented either with 4.2 or 8.3g/d of supplemental methionine from a ruminally protected source or with 2.7 or 5.3g/d of supplemental methionine from meSBM-Met. All diets were formulated to provide adequate amounts of metabolizable lysine. Concentration of milk true protein was greater when methionine was provided by the ruminally protected methionine than by meSBM-Met, but milk protein yield was not affected by treatment. Milk yields and concentrations and yields of fat, lactose, solids-not-fat, and milk urea nitrogen were not affected by supplemental methionine. Body condition scores increased linearly when methionine from meSBM-Met was supplemented, but responses were quadratic when methionine was provided from a ruminally protected source. Nitrogen retention was not affected by supplemental methionine. Plasma methionine increased linearly when methionine was supplemented from a ruminally protected source, but plasma methionine concentrations did not differ from the control when supplemental methionine from meSBM-Met was provided. In vitro degradation of supplemental methionine from meSBM-Met was complete within 3h. Data suggest that meSBM-Met provides negligible amounts of metabolizable methionine to dairy cows, and this is likely related to extensive ruminal destruction of methionine; however, cow body condition may be improved by ruminally available methionine provided by meSBM-Met.

Effect of fat additions to diets of dairy cattle on milk production and components: a meta-analysis and meta-regression

The objectives of this study were to critically review randomized controlled trials, and quantify, using meta-analysis and meta-regression, the effects of supplementation with fats on milk production and components by dairy cows. We reviewed 59 papers, of which 38 (containing 86 comparisons) met eligibility criteria. Five groups of fats were evaluated: tallows, calcium salts of palm fat (Megalac, Church and Dwight Co. Inc., Princeton, NJ), oilseeds, prilled fat, and other calcium salts. Milk production responses to fats were significant, and the estimated mean difference was 1.05 kg/cow per day, but results were heterogeneous. Milk yield increased with increased difference in dry matter intake (DMI) between treatment and control groups, decreased with predicted metabolizable energy (ME) balance between these groups, and decreased with increased difference in soluble protein percentage of the diet between groups. Decreases in DMI were significant for Megalac, oilseeds, and other Ca salts, and approached significance for tallow. Feeding fat for a longer period increased DMI, as did greater differences in the amount of soluble protein percentage of the diet between control and treatment diets. Tallow, oilseeds, and other Ca salts reduced, whereas Megalac increased, milk fat percentage. Milk fat percentage effects were heterogeneous for fat source. Differences between treatment and control groups in duodenal concentrations of C18:2 and C 18:0 fatty acids and Mg percentage reduced the milk fat percentage standardized mean difference. Milk fat yield responses to fat treatments were very variable. The other Ca salts substantially decrease, and the Megalac and oilseeds increased, fat yield. Fat yield increased with increased DMI difference between groups and was lower with an increased estimated ME balance between treatment and control groups, indicating increased partitioning of fat to body tissue reserves. Feeding fats decreased milk protein percentage, but results were heterogeneous. An increased number of milkings increased the milk protein percentage, whereas the difference between the treatment and control groups in duodenal concentrations of 18:2 fatty acids and dietary Mg concentration reduced the milk protein percentage. None of the fat treatments influenced milk protein production. The range of responses to different fats fed approached or exceeded 5 standard deviations from the mean and differed in point direction for all variables studied, indicating the varied and profound biological effects of fats. Responses to fat feeding were highly heterogeneous for all variables studied and heterogeneity was present within responses to individual fat groups. The lower DMI combined with higher milk and milk fat production showed that fats could improve the efficiency of milk production. More studies are required to more completely characterize sources of variation in responses to fats.

Determining the Amount of Rumen-Protected Methionine Supplement That Corresponds to the Optimal Levels of Methionine in Metabolizable Protein for Maximizing Milk Protein Production and Profit on Dairy Farms

The profitability of feeding rumen-protected Met (RPMet) sources to produce milk protein was estimated using a 2-step procedure: First, the effect of Met in metabolizable protein (MP) on milk protein production was estimated by using a quadratic Box-Cox functional form. Then, using these estimation results, the amounts of RPMet supplement that corresponded to the optimal levels of Met in MP for maximizing milk protein production and profit on dairy farms were determined. The data used in this study were modified from data used to determine the optimal level of Met in MP for lactating cows in the Nutrient Requirements of Dairy Cattle (NRC, 2001). The data used in this study differ from that in the NRC (2001) data in 2 ways. First, because dairy feed generally contains 1.80 to 1.90% Met in MP, this study adjusts the reference production value (RPV) from 2.06 to 1.80 or 1.90%. Consequently, the milk protein production response is also modified to an RPV of 1.80 or 1.90% Met in MP. Second, because this study is especially interested in how much additional Met, beyond the 1.80 or 1.90% already contained in the basal diet, is required to maximize farm profits, the data used are limited to concentrations of Met in MP above 1.80 or 1.90%. This allowed us to calculate any additional cost to farmers based solely on the price of an RPMet supplement and eliminated the need to estimate the dollar value of each gram of Met already contained in the basal diet. Results indicated that the optimal level of Met in MP for maximizing milk protein production was 2.40 and 2.42%, where the RPV was 1.80 and 1.90%, respectively. These optimal levels were almost identical to the recommended level of Met in MP of 2.40% in the NRC (2001). The amounts of RPMet required to increase the percentage of Met in MP from each RPV to 2.40 and 2.42% were 21.6 and 18.5 g/d, respectively. On the other hand, the optimal levels of Met in MP for maximizing profit were 2.32 and 2.34%, respectively. The amounts of RPMet required to increase the percentage of Met in MP from each RPV to 2.32 and 2.34% were 18.7 and 15.6 g/d, respectively. In each case, the additional daily profit per cow was estimated to be $0.38 and $0.29. These additional profit estimates were $0.02 higher than the additional profit estimates for maximizing milk protein production.

Effect of Dietary Level of Rumen-Degraded Protein on Production and Nitrogen Metabolism in Lactating Dairy Cows

Twenty-eight (8 with ruminal cannulas) lactating Holstein cows were assigned to 4 x 4 Latin squares and fed diets with different levels of rumen-degraded protein (RDP) to study the effect of RDP on production and N metabolism. Diets contained [dry matter (DM) basis] 37% corn silage, 13% alfalfa silage, and 50% concentrate. The concentrate contained solvent and lignosulfonate-treated soybean meal and urea, and was adjusted to provide RDP at: 13.2, 12.3, 11.7, and 10.6% of DM in diets A to D, respectively. Intake of DM and yield of milk, fat-corrected milk, and fat were not affected by treatments. Dietary RDP had positive linear effects on milk true protein content and microbial non-ammonia N (NAN) flow at the omasal canal, and a quadratic effect on true protein yield, with maximal protein production at 12.3% RDP. However, dietary RDP had a positive linear effect on total N excretion, with urinary N accounting for most of the increase, and a negative linear effect on environmental N efficiency (kg of milk produced per kg of N excreted). Therefore, a compromise between profitability and environmental quality was achieved at a dietary RDP level of 11.7% of DM. Observed microbial NAN flow and RDP supply were higher and RUP flow was lower than those predicted by the NRC (2001) model. The NRC (2001) model overpredicted production responses to RUP compared with the results in this study. Replacing default NRC degradation rates for protein supplements with rates measured in vivo resulted in similar observed and predicted values, suggesting that in situ degradation rates used by the NRC are slower than apparent rates in this study.

Impacts of the source and amount of crude protein on the intestinal supply of nitrogen fractions and performance of dairy cows

The objective of this article was to review and summarize the significance of the amount and source of dietary crude protein supplements on the supply of nitrogen fractions passing to the small intestine and the performance of lactating dairy cows. A meta-analysis was used to evaluate 2 data sets, one for nitrogen flow to the small intestine and one for performance of cows. The response of dairy cows to rumen-undegradable protein supplements is variable. A portion of this variable response from research trials is explained by the source of crude protein in the control diet, the proportion and source of rumen-undegradable protein in the experimental diet, the effect of rumen-undegradable protein on microbial protein outflow from the rumen, the degradability and amino acid content of the rumen-undegradable protein, and the crude protein percentage of the diet. Compared with soybean meal, the mean milk production responses to feeding rumen-undegradable protein supplements ranged from -2.5 to +2.75%. Because of the large variation and small magnitude of response when rumen-undegradable protein supplements are fed compared with soybean meal, efficiency of nitrogen utilization and the cost to benefit ratio for these crude protein supplements may determine the source and amount of crude protein to feed to dairy cows in the future.

Effect of Two Levels of Crude Protein and Methionine Supplementation on Performance of Dairy Cows

Sixteen Holstein cows in midlactation were randomly assigned to treatments in a replicated 4 x 4 Latin square. Two levels of CP (16.1 vs. 18.8%) with or without supplemental methionine (0.07 g/100 g of DM) were tested in a 2 x 2 factorial arrangement of treatments. Dry matter intake, milk production, milk composition, and N excretion were determined. No interactions between CP level and methionine supplementation were observed. Milk production and dry matter intake were not different among treatments. Milk protein concentration increased from 3.17 to 3.26% with the addition of methionine and decreased from 3.24 to 3.17% with increased CP. No differences were observed among treatments in milk protein yield. Milk fat concentration was low across all diets, but was increased from 2.33% with 16.1% CP diets to 2.68% with 18.8% CP diets. No significant treatment effects were observed for SNF, lactose concentration in milk, or casein N as a fraction of skim milk N. Increased dietary CP increased milk urea N by 3.9 mg/dl. Methionine supplementation did not affect N excretion in urine or feces. The higher protein diets increased estimated urine volume by 2.9 L/d and increased N concentration by 1.7 percentage units in both urine and feces. Feeding higher protein increased milk urea and urine N excretion as expressed as a percentage of total N excreted (44 vs. 38% for 18.8 and 16.1% CP, respectively). Overall, feeding 16.1% CP produced milk and milk protein yields similar to feeding 18.8% CP, but reduced the N losses in urine and milk urea.

Evaluation of ruminally protected methionine and lysine or blood meal and fish meal as protein sources for lactating Holsteins

Forty lactating Holstein cows averaging 55 days in milk were used in a randomized block designed experiment to evaluate the effectiveness of ruminally protected Met and Lys compared with that of ruminally undegradable protein for supporting lactation. Cows were fed total mixed diets for 15 wk. Diets were formulated to be isonitrogenous with the same base ingredients resulting in base crude protein percentage of 15.5. Supplemental crude protein supplied by urea, soybean meal, or a 50:50 (wt/wt) mixture of fish and blood meal increased total dietary nitrogen to 18.0% of diet DM. Two additional diets consisted of the basal diets soybean meal and urea, which were supplemented with ruminally protected DL-Met and Lys-HCL at 10 and 25 g/d, respectively (soybean meal + amino acids (AA), urea + AA). Mean measures of dry matter intake, milk yield, milk protein percentage, and milk fat percentage were not affected by protein supplement. Milk protein yield, milk fat yield, casein yield, and casein percentage also were not affected by source of supplemental protein. Results indicate that at the level of crude protein intake relative to milk production in this experiment, the source of protein did not affect lactational performance.

Synchronization of carbohydrate and protein sources on fermentation and passage rates in dairy cows

Four ruminally cannulated Holstein cows in midlactation were randomly assigned to a 4 x 4 Latin square design with a 2 x 2 factorial arrangement of treatments to evaluate two nonstructural carbohydrate sources (corn or barley) with two sources of ruminally undegradable protein (soybean meal or extruded soybean meal) on milk production, ruminal fermentation, and digesta passage rates. Milk production (25.1, 27.5, 23.8, and 23.5 kg/d for the corn and soybean meal, corn and extruded soybean meal, barley and soybean meal, and barley and extruded soybean meal, respectively) and dry matter intake per unit of body weight (3.9, 4.1, 3.7, and 3.7%) were greater for cows fed corn than for cows fed barley and were similar for cows fed soybean meal or extruded soybean meal. Concentrations of ruminal NH3-N were greater for cows fed the corn and soybean meal diet than for cows fed other diets (15.0, 10.4, 9.0, and 11.3 mg/dl). Rumen volatile fatty acid concentrations were greater for cows fed corn than barley (133, 139, 121, and 118 mumol/ml). Fractional passage rates of solids from the rumen were greater for cows fed the barley and soybean meal diet than cows fed the corn and soybean meal diet (3.4, 3.9, 4.2, and 3.8%/h), and ruminal liquid dilution rates were similar for cows fed all diets (11.2, 11.0, 11.1, and 11.9%/h). The attempt to synchronize ruminal nonstructural carbohydrate and crude protein degradability produced minimal benefits for midlactation dairy cows.

Effects of rumen-undegradable protein on dairy cow performance: a 12-year literature review

In order to integrate and analyze knowledge on the use of protein supplements and protein nutrition of lactating dairy cows, we compiled a review of 108 studies published throughout the world, but principally in the Journal of Dairy Science between 1985 and 1997. In 29 comparisons from 15 metabolism trials, soybean meal was replaced by high amounts of rumen undegradable protein (RUP) as a supplement; the benefits were not consistently observed for flow to the duodenum, essential amino acids, or lysine and methionine. High RUP diets resulted in decreased microbial protein synthesis in 76% of the comparisons. However, fish meal provided a good balance of lysine and methionine when calculated as a percentage of total essential amino acids. In 127 comparisons from 88 lactation trials that were published from 1985 to 1997, researchers studied the effects of replacing soybean meal with high RUP sources, such as heated and chemically treated soybean meal, corn gluten meal, distillers grains, brewers grains, blood meal, meat and bone meal, feather meal, or blends of these sources; milk yield was significantly higher in only 17% of the comparisons. Fish meal and treated soybean meal accounted for most of the positive effects on milk yield from RUP; corn gluten meal resulted in mostly negative results. The percentage of fat in milk was depressed more by fish meal than by other RUP sources. Protein percentage was decreased in 28 comparisons and increased in only 6 comparisons, probably reflecting the decrease in microbial protein synthesis, as was observed for diets high in RUP. The data strongly suggest that increased RUP per se in dairy cow diets, which often results in a decrease in RDP and a change in absorbed AA profiles, does not consistently improve lactational performance.

Effects of heat treatment and physical processing of cottonseed on nutrient digestibility and production performance by lactating cows

Four primiparous Holstein cows were used in an experiment with a 5 x 4 Youden square design. The effects of heat processing and particle size of cottonseed used in the diets of dairy cows were investigated. Dietary treatments were control (3.6% tallow, 4.5% casein), whole cottonseed, ground cottonseed, roasted whole cottonseed, and roasted ground cottonseed. Diets consisted of 55% corn silage, 1.54% urea, and cottonseed at 18.1% or dry matter. Cottonseeds were roasted at 149 degrees C and steeped for 30 min. Roasting increased the amount of ruminally undegradable protein measured in vivo, the ratio of ruminal acetate to propionate, pH, and milk protein percentage. Ruminal digestibilities of organic matter (OM) and neutral detergent fiber and biohydrogenation of fatty acids were reduced by roasting. The grinding of cottonseed increased the total tract digestibility of OM and N and tended to increase ruminally undegradable protein of cottonseed in vivo. Interactions between heat treatment and particle size of cottonseed revealed that roasted ground cottonseed resulted in the highest total tract digestibility of OM, N, and neutral detergent fiber. Utilization of cottonseed may be improved by heat or mechanical processing as was indicated by this study.

Response of lactating cows to methionine or methionine plus lysine added to high protein diets based on alfalfa and heated soybeans

Lactation diets based on wilted alfalfa silage and heated whole soybeans are common in the midwestern US. We examined the milk production response of multiparous Holstein cows to the addition of ruminally protected methionine at two percentages to a basal total mixed ration. An additional total mixed ration included both methionine and lysine supplementation. Sixteen Holstein cows in early lactation were used in a replicated 4 x 4 Latin square design with 21-d periods. Milk production, milk composition, and dry matter intake were determined for the last 5 d of each period. Milk production (41.5 kg/d), dry matter intake (25.9 kg/d), and milk fat concentration (3.26%) were unaffected by the supplementation of amino acids. The addition of methionine increased milk protein concentration and yield linearly. Each gram of methionine increased milk protein yield by 4 g, and milk protein concentration increased from 2.89 to 2.99% with the addition of 10.5 g/d of methionine. The proportion of casein N in total milk N was unaffected by treatment. The addition of lysine did not elicit a response. Total mixed rations based on alfalfa haylage, heated soybeans, and animal proteins were clearly limited by their methionine content but were adequate in their lysine content.

Performance and profiles of milk fatty acids of cows fed full fat, heat-treated soybeans using various processing methods

Twenty-four multiparous Holstein cows (48 d in lactation) were used in an 8-wk trial employing a completely randomized block design to determine the effect of heat treatment of full fat soybeans on the fatty acid composition of milk fat. Treatments consisted of a total mixed ration supplemented with 1) ground raw, 2) extruded, 3) micronized, or 4) roasted soybeans included at 17.5% of the dry matter of the total mixed ration. Dietary treatment had no effect on body weight, yields of milk or solids-corrected milk, fat percentage, or yield of milk fat or protein. Cows fed ground raw soybeans had a higher dry matter intake and a higher percentage of protein in milk than those fed heat-treated soybeans. The concentrations of saturated fatty acids from C8:0 to C16:0 were lower, and cis-delta-9-C18:1 tended to be higher, in the milk fat of cows fed heat-treated soybeans than in the milk fat of cows fed ground raw soybeans. The concentration of trans-delta-11-C18:1 was lowest for cows fed ground raw soybeans, intermediate for cows fed micronized and roasted soybeans, and highest for cows fed extruded soybeans. Cows fed extruded soybeans had lower concentrations of C18:2 and C18:3 than did cows fed micronized or roasted soybeans; cows fed ground raw soybeans had intermediate concentrations of C18:2 and C18:3.

Roasted soybeans, blood meal, and tallow as sources of fat and ruminally undegradable protein in the diets of lactating cows

The effect of roasted soybeans, blood meal, and tallow as sources of fat and RUP for lactating dairy cows was studied. Forty-five cows, blocked by age, calving date, and milk yield during the previous lactation, were assigned randomly to the following treatments (ingredient in the DM, RUP as a percentage of CP, and fat in the DM, respectively): 1) soybean meal (16, 35, and 3.2%), 2) whole roasted soybeans (18, 40, and 6.2%), 3) ground roasted soybeans (18, 40, and 6.2%), 4) blood meal (2.7, 40, and 3.2%), and 5) blood meal plus tallow (2.7 and 3, 40, and 6.2%). Diets were fed from wk 3 to 18 of lactation and consisted of 20% alfalfa silage, 30% corn silage, and 50% concentrate. The DMI of blood meal and whole roasted soybean diets was about 11% lower than DMI of the soybean meal diet. Milk yield (38.4 kg/d) and milk fat percentage (3.37%) were similar among diets. The roasted soybean diets resulted in the lowest milk protein percentage. Less than 2.7% blood meal might be advisable for diets fed to high yielding dairy cows to avoid reduced DMI.

Evaluation of a ruminally protected methionine product for lactating dairy cows

In Experiment 1, three ruminally and duodenally cannulated cows were used to assess the extent of ruminal protection and postruminal release of Met from ruminally protected Met using a polyester bag technique. The ruminally protected Met contained 85.1% DL-Met (wt/wt). Ruminal disappearance of Met averaged 5.8, 8.1, 21.8, 37.5, and 87.5% after 3, 6, 12, 24, and 96 h of incubation, respectively. Postruminal disappearance of Met from bags inserted in the duodenum after treatment with pepsin-HCl averaged 63.4, 62.6, 51.6, 43.6, and 8.8% for bags incubated in the rumen for 3, 6, 12, 24, and 96 h, respectively. In Experiment 2, 12 cows were fed either 0 or 20 g/d of ruminally protected Met from 7 to 10 d prepartum until 18 wk postcalving. Cows were fed the same total mixed diet. The DMI; yields of milk, CP, and SNF; and percentages of fat, CP, and SNF in milk were not affected by treatment. However, yields of fat and 3.5% FCM increased when ruminally protected Met was fed. Milk N components were not affected by treatment. Concentrations of Met increased in plasma when ruminally protected Met was fed. The mechanism for the increased production of milk fat and 3.5% FCM when ruminally protected Met was fed is unknown.

Interactions of ruminally protected methionine and lysine with protein source or energy level in the diets of cows

Interactions between supplementation with ruminally protected Met and Lys and the nature of protein or energy concentration of the diet were studied using 16 and 12 multiparous lactating dairy cows in two trials of 8 and 12 wk, respectively, commencing on approximately d 40 of lactation. In trial 1, cows received a semicomplete diet plus concentrates. The diet consisted of 62 to 63% corn silage, 2.2% corn gluten meal, .4% urea, 11% soybean meal (untreated or treated with formaldehyde), and 23 to 24% barley. In trial 2, cows received a complete diet with corn silage, untreated and formaldehyde-treated soybean meal, and barley in the ratio 78:12:9:0 or 49:13:4:33. All treatments were replicated in a 4 x 4 Latin square design. In both trials, Met plus Lys (10 g/d of intestinally available Met and 30 g/d of Lys) has no significant effect on DMI, milk yield, fat content, casein as a percentage of true protein, or urea content of the milk. Mean increase of milk protein yield was 46 g/d with Met plus Lys, and mean increase of true protein content was 1.1 g/kg of milk. The increase in content of milk true protein was greater for cows receiving the low energy diet. Protein source had no effect on milk yield or composition. Glucose, urea, NEFA, BHBA, and total free AA in plasma were unaffected by supplementation of ruminally protected Met plus Lys. However, concentrations of Met and Lys in blood were slightly, but not significantly, higher in supplemented cows.

Nonstructural carbohydrate and undegradable protein sources in the diet: growth responses of dairy heifers

Thirty-five 3-mo-old 150-kg Holstein heifers were fed diets containing two nonstructural carbohydrate sources (corn or barley) with two quantities of undegradable protein (soybean meal or extruded soybean meal) for 9 wk in a 2 x 2 factorial arrangement to evaluate NRC guidelines that the diet contain increased quantities of undegraded intake protein. Total mixed diets fed for ad libitum intake contained approximately 17.4% CP, consisting of 16.7% corn silage (DM basis), 33.3% chopped alfalfa hay, and 50% concentrate mix. Average daily gains were greater for heifers fed extruded soybean meal, but response was greater when heifers were fed barley-extruded soybean meal (1.12, 1.13, 1.05, and 1.23 kg/d for corn-soybean meal, corn-extruded soybean meal, barley-soybean meal, and barley-extruded soybean meal, respectively) than diets of barley-soybean meal. Extruded soybean meal increased DMI (5.9, 6.1, 5.2, and 6.7 kg/d), but DMI were similar when diets based on corn or barley were fed. Diets with greater concentrations of undegraded intake protein fed to dairy heifers resulted in greater DMI and average daily gains, but responses were greater when heifers were fed diets based on barley rather than corn. These results suggest that current NRC recommendations for undegraded intake protein fed to 3- to 6-mo-old dairy heifers are too high; diets containing 35 to 40% undegraded intake protein should be sufficient.

Raw soybeans and roasted soybeans of different particle sizes. 2. Fatty acid utilization by lactating cows

This study was conducted to examine the effects of feeding whole raw soybeans and roasted soybeans of different particle sizes on utilization by ruminal bacteria and lactating cows. Five cows with ruminal and duodenal cannulas were used in a 5 x 5 Latin square design. Diets contained 55% corn silage and 45% concentrate. Treatments were control (Ca soaps at 4.24% of dietary DM), whole raw soybeans, whole roasted soybeans, cracked roasted soybeans, or ground roasted soybeans. All soybean diets contained 19.7% soybeans. Source of fat (Ca soaps vs. soybeans) caused more differences in utilization of fatty acids than did processing of soybeans. Ruminal bacteria harvested from cows fed roasted soybeans had higher fatty acid content than from cows fed raw soybeans. Different methods for calculation of ruminal biohydrogenation of fatty acids are discussed. Roasting tended to increase the total tract digestibility of fatty acids, and roasted soybeans tended to increase polyunsaturated fatty acids in milk compared with raw soybeans, primarily because of changes in concentration of C18:2. Change in particle size of roasted soybeans had minor effects on utilization of fatty acids. Decisions on processing of soybeans need to be based primarily on factors other than fatty acid digestibility.

Dietary fat and adipose tissue metabolism in ruminants, pigs, and rodents: a review

Effects of dietary fat on dairy cows are reviewed. Dietary fat did not affect gain in BW or body condition score after peak lactation but tended to increase BW loss during early lactation and body fat deposition in growing cattle. Dietary fat decreased de novo fatty acid synthesis in adipose tissue. Basal FFA release from adipose tissue in vitro and beta-adrenergic lipolytic responses were increased by protected polyunsaturated fatty acids. Dietary fat increased body fat in growing pigs and decreased BW loss in lactating sows. Dietary fat decreased de novo fatty acid synthesis and basal glycerol release in adipose tissue and tended to increase simultaneously beta-adrenergic lipolytic responses to increased membrane fluidity. Dietary fat increased body fat in rats. Polyunsaturated fatty acids were sometimes less efficient than saturated ones in increasing body fat. Lipoprotein lipase activity in adipose tissue generally decreased. Hepatic fatty acid synthesis was decreased sharply by polyunsaturated fatty acids, and adipose tissue response was less important. beta-Adrenergic-stimulated lipolysis decreased, and fatty acid esterification increased, particularly from saturated fatty acids. A trend toward insulin resistance, which was more marked with saturated fatty acids, occurred in adipose tissue.

Lactation response to ruminally protected methionine and lysine at two amounts of ruminally available nitrogen

Sixty multiparous Holsteins were used in a 200-d continuous lactation trial designed to measure the response to a mixture of ruminally protected Met and Lys. Response to AA was determined at two dietary concentrations of degraded protein designed to provide 85 and 100% of NRC recommended amounts. This difference in degraded protein content was achieved by addition of urea. Diets without urea supported lactation as well as diets with added urea in early lactation. In midlactation, urea addition was detrimental to yields of milk and milk protein; addition of AA prevented this negative effect. In early lactation, AA addition raised milk protein concentration and yield by 1 g/kg of milk of 37 g/d and did not interact with urea. Increases in protein concentration in response to AA addition were similar in early and late lactation and corresponded to changes in the casein fraction of milk. These results support previous work showing the importance of adequate absorbable Lys and Met to maximize the protein content of milk. The results suggest that interactions may occur between ruminal ammonia production and AA supply.

Nutrient requirements versus supply in the dairy cow: strategies to account for variability

Dairy producers must overcome substantial challenges to achieve milk outputs > 14,000 kg of milk/yr per cow within the next decade. To obtain high productivity, a more complete comprehension of the dynamics of metabolism, nutrient utilization, and nutrient absorption will enable better prediction of the efficiency of utilization of these nutrients. A better understanding of the dynamics of rumen function and a more accurate prediction of nutrient flow from the rumen are necessary. Grouping strategy and group feeding behavior influence cow productivity and farm profitability. Understanding of the variance of individual cow responses to management practice is critical. Feeding system design and management and diet formulation techniques need to be developed that recognize the dynamic nature of cow physiology and the variability in feedstuffs and cow requirements. These concepts need to be integrated into total farm management and require the use of new computer modeling technologies.

Supplemental dietary fat from extruded soybeans and calcium soaps of fatty acids for lactating cows

Holstein cows (n = 33) were assigned to one of three diets containing soybean meal, supplemental fat from extruded soybeans, or supplemental fat from Ca soaps of fatty acids. Total mixed diets containing (DM basis) 25% corn silage, 25% alfalfa hay, and 50% of the respective concentrate mixtures were fed wk 4 through 15 postpartum. Milk production (29.2, 32.4, and 31.8 kg/d) was higher for cows fed supplemental fat diets. Milk protein percentages (2.99, 2.93, and 2.81) were higher for cows fed the soybean meal diet and were higher with extruded soybeans than with Ca soaps of fatty acids. Milk fat percentages (3.20, 2.69, and 3.47) were higher for cows fed Ca soaps of fatty acids than for cows fed extruded soybeans. Milk fat from cows fed supplemental fat was more unsaturated than from those fed soybean meal and was most unsaturated from cows fed extruded soybeans. Dry matter intakes (17.8, 18.4, and 16.6 kg/d) were not significantly different among diets. Extruded soybeans and Ca soaps of fatty acids were equally effective in increasing milk production, but milk fat content was reduced, and the proportion of unsaturated fatty acids in milk fat was increased, with extruded soybeans.

Effect of somatotropin administration and duodenal infusion of methionine and lysine on lactational performance and nutrient flow to the small intestine

Lack of sufficient methionine and lysine delivered post-ruminally may limit milk production response to bovine somatotropin (bST). To test this hypothesis, four Holstein cows fitted with rumen and duodenal cannulas were used in a 4 x 4 Latin square design with 14 d periods. Treatments were: (1) control, (2) continuous duodenal infusion of 8 g methionine and 24 g lysine/d, (3) injection of 25 mg bST/d and (4) infusion of methionine and lysine plus injection of bST. Infusion of amino acids led to trends for small increases in milk (3%), fat (5.5%), and protein (3.7%) yield. Larger and significant increases (8.7, 14 and 6.9% for milk, fat and protein yield respectively) were achieved with bST administration which also increased milk fat content. Plasma levels of urea-N and essential amino acids were reduced with bST. Duodenal nutrient flow was generally unaffected by treatment. The production response to bST was not enhanced in cows producing an average of 34 kg milk when provided additional methionine and lysine post-ruminally in this short-term study.

Amino acid limitation and flow to duodenum at four stages of lactation. 1. Sequence of lysine and methionine limitation

Four Holstein cows with ruminal and duodenal cannulas were assigned to a 4 x 4 Latin square at each of four stages of lactation (peak, wk 4; early, wk 8 to 12; mid, wk 17 to 21; and late, wk 27 to 31). Treatments were duodenal infusions of 1) Met, 2) Lys, 3) Met plus Lys, and 4) casein; periods were 7 to 10 d. Quantities of DL-Met, L-Lys, and casein infused at the four stages of lactation were 12, 30, and 400; 12, 30, and 400; 10, 25, and 333; and 8, 20, and 266 g/d, respectively. Rations were composed of corn and grass-legume silages, corn meal, wheat middlings, soybean meal, and distillers dried grains with solubles. Intake of CP (percentage of NRC) and percentage of total CP from corn sources were (peak) 87, 56; (early) 90, 71; (mid) 98, 73; and (late) 114, 77. Using content and yield of milk protein as primary response criteria, Lys appeared to be first-limiting and Met second-limiting at peak lactation, their infusion together resulted in the same production of milk (40 kg/d) and milk protein (1135 g/d) as did casein. Lysine was first-limiting in early lactation, but whether Met was second-limiting was questionable. The two AA were colimiting in midlactation. There appeared to be no AA deficiencies in late lactation. Amounts of Lys and Met (percentage of total essential AA) in duodenal digesta during peak (12.4, 3.7), early (12.6, 3.5), and midlactation (14.9, 3.9) were not adequate for optimal AA utilization.

Effects of feeding lactating dairy cows diets containing extruded soybeans and calcium salts of long-chain fatty acids

Four multiparous Holstein cows averaging 36 DIM and fitted with ruminal cannulas were utilized in a 4 x 4 Latin square design to investigate the effects of feeding extruded whole soybeans and Ca salts of long-chain fatty acids. Treatments were diets containing 1) no added fat, 2) 16% extruded whole soybeans, 3) 16% extruded whole soybeans and 3% Ca salts of long-chain fatty acids, and 4) 16% extruded whole soybeans and 6% Ca salts of long-chain fatty acids. Cows were fed for ad libitum intake a diet of alfalfa haylage, corn silage, and concentrate (35:15:50, DM basis). Intakes of DM and energy and production of milk, 4% FCM, fat, CP, and SNF were decreased by feeding extruded whole soybeans and 6% Ca salts of long-chain fatty acids, but differences were small among the other treatments. The weight percentages and yields of C18:0, C18:1, and C18:2 in milk were increased, and most shorter chain fatty acids were decreased, by feeding supplemental fat. Digestibilities of DM, OM, ADF, soluble residue, total C18 fatty acids, and total fatty acids were decreased, but digestibility of hemicellulose was increased by feeding supplemental fat. The largest decrease in digestibilities of most dietary constituents and in energy and N utilization occurred when 16% extruded whole soybeans plus 6% Ca salts of long-chain fatty acids were fed to the cows. Calcium salts of long-chain fatty acids can supply up to 3% of the dietary DM in diets containing 16% extruded whole soybeans without having deleterious effects on most variables measured in this experiment.