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Hanigan MD, Souza VC, Martineau R, Lapierre H, Feng X, Daley VL. A meta-analysis of the relationship between milk protein production and absorbed amino acids and digested energy in dairy cattle. J Dairy Sci 2024; 107:5587-5615. [PMID: 38490550 DOI: 10.3168/jds.2024-24230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Accepted: 02/09/2024] [Indexed: 03/17/2024]
Abstract
Milk protein production is the largest draw on AA supplies for lactating dairy cattle. Prior NRC predictions of milk protein production have been absorbed protein (MP)-based and used a first-limiting nutrient concept to integrate the effects of energy and protein, which yielded poor accuracy and precision (root mean squared error [RMSE] >21%). Using a meta-data set gathered, various alternative equation forms considering MP, absorbed total EAA, absorbed individual EAA, and digested energy (DE) supplies as additive drivers of production were evaluated, and all were found to be superior in statistical performance to the first limitation approach (RMSE = 14%-15%). Inclusion of DE intake and a quadratic term for MP or absorbed EAA supplies were found to be necessary to achieve intercept estimates (nonproductive protein use) that were similar to the factorial estimates of the National Academies of Sciences, Engineering, and Medicine (2021). The partial linear slope for MP was found to be 0.409, which is consistent with the observed slope bias of -0.34 g/g when a slope of 0.67 was used for MP efficiency in a first-limiting nutrient system. Replacement of MP with the supplies of individual absorbed EAA expressed in grams per day and a common quadratic across the EAA resulted in unbiased predictions with improved statistical performance as compared with MP-based models. Based on Akaike's information criterion and biological consistency, the best equations included absorbed His, Ile, Lys, Met, Thr, the NEAA, and individual DE intakes from fatty acids, NDF, residual OM, and starch. Several also contained a term for absorbed Leu. These equations generally had RMSE of 14.3% and a concordance correlation of 0.76. Based on the common quadratic and individual linear terms, milk protein response plateaus were predicted at approximately 320 g/d of absorbed His, Ile, and Lys; 395 g/d of absorbed Thr; 550 g/d of absorbed Met; and 70 g/d of absorbed Leu. Therefore, responses to each except Leu are almost linear throughout the normal in vivo range. De-aggregation of the quadratic term and parsing to individual absorbed EAA resulted in nonbiological estimates for several EAA indicating over-parameterization. Expression of the EAA as g/100 g total absorbed EAA or as ratios of DE intake and using linear and quadratic terms for each EAA resulted in similar statistical performance, but the solutions had identifiability problems and several nonbiological parameter estimates. The use of ratios also introduced nonlinearity in the independent variables which violates linear regression assumptions. Further screening of the global model using absorbed EAA expressed as grams per day with a common quadratic using an all-models approach, and exhaustive cross-evaluation indicated the parameter estimates for BW, all 4 DE terms, His, Ile, Lys, Met, and the common quadratic term were stable, whereas estimates for Leu and Thr were known with less certainty. Use of independent and additive terms and a quadratic expression in the equation results in variable efficiencies of conversion. The additivity also provides partial substitution among the nutrients. Both of these prevent establishment of fixed nutrient requirements in support of milk protein production.
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Affiliation(s)
- M D Hanigan
- Department of Dairy Science, Virginia Tech, Blacksburg, VA 24061.
| | - V C Souza
- Department of Dairy Science, Virginia Tech, Blacksburg, VA 24061
| | - R Martineau
- Agriculture and Agri-Food Canada, Sherbrooke, QC, Canada J1M 0C8
| | - H Lapierre
- Agriculture and Agri-Food Canada, Sherbrooke, QC, Canada J1M 0C8
| | - X Feng
- Department of Dairy Science, Virginia Tech, Blacksburg, VA 24061
| | - V L Daley
- Department of Dairy Science, Virginia Tech, Blacksburg, VA 24061
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Artavia G, Cortés-Herrera C, Granados-Chinchilla F. Total and resistant starch from foodstuff for animal and human consumption in Costa Rica. Curr Res Food Sci 2020; 3:275-283. [PMID: 33305294 PMCID: PMC7711177 DOI: 10.1016/j.crfs.2020.11.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Starchy ingredients are a key source of carbohydrates and have an essential role in a healthy diet. Starch amount in foodstuffs is paramount as it allows diet professionals to base their formulations on scientific data. Herein, the total (TS) and resistant starch (RS) content, in a selection of typical starchy foods available on the Costa Rican market, for both human and animal consumption, is reported. The major types of starch, including physically encapsulated starch, were determined using in vitro methods AOAC OMASM methods 996.11, 2014.10, 996.11, 2002.02 and AACC 76-13.01 and 32-40.01. Samples were collected during 5 years as part of national surveillance plans. For feedstuffs, n = 252 feed ingredients (e.g., cornmeal and wheat products), n = 103 feeds (e.g., dairy and beef cattle), and n = 150 feed ingredient samples (selected based on their usage in feed formulations) were assessed for RS. In food commodities, sample numbers ascended to n = 287 and n = 371 for TS and RS, respectively (e.g. bananas). Feed ingredients with higher TS values were cassava meal, bakery by-products, rice/broken, sweet potato, and cornmeal (93.37, 81.67, 72.33, 66.66, and 61.43 g/100 g, respectively). TS for beef and dairy cattle, pig, and calf feeds, ranged from 30.26 to 34.46 g/100 g. Plantain/green banana flour, as a feed ingredient, exhibited RS absolute and relative contributions of 37.04 g/100 g and 53.89%, respectively. Products with a higher TS content included banana flour, green plantain flour, japonica rice, and cassava flour (62.87, 63.10, 72.90, 83.37 g/100 g). The primary RS sources in the Costa Rican diet are, in absolute terms, green plantain and malanga (50.41 and 56.59 g/100 g). Depending on a person's food habits, these sources may contribute in the range of 20-30 grams of RS per day. TS and RS intake may vary considerably among ingredients, and the contribution of RS may be of nutritional importance for specific individuals.
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Affiliation(s)
- Graciela Artavia
- Centro Nacional de Ciencia y Tecnología de Alimentos (CITA), Universidad de Costa Rica, San José, Costa Rica
| | - Carolina Cortés-Herrera
- Centro Nacional de Ciencia y Tecnología de Alimentos (CITA), Universidad de Costa Rica, San José, Costa Rica
| | - Fabio Granados-Chinchilla
- Centro de Investigación en Nutrición Animal (CINA), Universidad de Costa Rica, 11501-2060 Ciudad Universitaria Rodrigo Facio San José, Costa Rica
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Abstract
During recent decades, the UK dairy industry has had to adjust to the introduction of milk quotas in 1984, the deregulation of milk markets in 1994, and accommodate changes in the demand for dairy products. The combination of these factors, in addition to Bovine Spongiform Encephalopathy and Foot and Mouth disease, and a fall in milk price has inevitably resulted in a restructuring of the industry, but also reinforced the need for all sectors of the industry to respond to the prevailing economic climate and changes in consumer preferences.
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Alemu AW, Dijkstra J, Bannink A, France J, Kebreab E. Rumen stoichiometric models and their contribution and challenges in predicting enteric methane production. Anim Feed Sci Technol 2011. [DOI: 10.1016/j.anifeedsci.2011.04.054] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Kuoppala K, Rinne M, Ahvenjärvi S, Nousiainen J, Huhtanen P. The effect of harvesting strategy of grass silage on digestion and nutrient supply in dairy cows. J Dairy Sci 2010; 93:3253-63. [DOI: 10.3168/jds.2009-3013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2009] [Accepted: 03/24/2010] [Indexed: 11/19/2022]
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Van Vuuren AM, Hindle VA, Klop A, Cone JW. Effect of maize starch concentration in the diet on starch and cell wall digestion in the dairy cow. J Anim Physiol Anim Nutr (Berl) 2009; 94:319-29. [DOI: 10.1111/j.1439-0396.2008.00911.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Cooke KM, Bernard JK, West JW. Performance of dairy cows fed annual ryegrass silage and corn silage with steam-flaked or ground corn. J Dairy Sci 2008; 91:2417-22. [PMID: 18487664 DOI: 10.3168/jds.2007-0715] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Twenty-four lactating Holstein cows were used in a 6-wk randomized block design trial with a 2 x 2 factorial arrangement of treatments to determine the effects of feeding ground corn (GC) or steam-flaked corn (SFC) in diets based on either annual ryegrass silage (RS) or a 50:50 blend of annual ryegrass and corn silages (BLEND). Experimental diets contained 49.6% forage and were fed as a total mixed ration once daily for 4 wk after a 2-wk preliminary period. No interactions were observed among treatments. Cows fed BLEND consumed more dry matter (DM), organic matter (OM), neutral detergent fiber (NDF), and acid detergent fiber (ADF) than those fed RS, but total-tract digestibility of OM, NDF, and ADF was greater for RS than for BLEND. No differences in nutrient intake were observed among treatments during wk 4 when nutrient digestibility was measured, but digestibility of DM and OM was greater for SFC than for GC. Cows fed BLEND tended to produce more energy-corrected milk than those fed RS, resulting in improved efficiency (kg of milk per kg of DM intake). When diets were supplemented with SFC, cows consumed less DM and produced more milk that tended to have lower milk fat percentage. Yield of milk protein and efficiency was greatest with SFC compared with GC. Blood glucose and milk urea nitrogen concentrations were similar among treatments, but blood urea nitrogen was greater for cows fed GC compared with those fed SFC. Results of this trial indicate that feeding a blend of annual ryegrass and corn silage is more desirable than feeding diets based on RS as the sole forage. Supplementing diets with SFC improved performance and efficiency compared with GC across forage sources.
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Affiliation(s)
- K M Cooke
- Department of Animal and Dairy Science, University of Georgia, Tifton 31793-0748, USA
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Gregorini P, Gunter SA, Beck PA. Matching plant and animal processes to alter nutrient supply in strip-grazed cattle: timing of herbage and fasting allocation. J Anim Sci 2008; 86:1006-20. [PMID: 18192561 DOI: 10.2527/jas.2007-0432] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
This work aimed to assess the impact of timing of herbage allocation and fasting on patterns of ingestive behavior, herbage intake, ruminal fermentation, nutrient flow to the duodenum, and site and extent of digestion. Treatments were daily herbage allocation in the afternoon (1500 h, AHA), morning (0800 h, MHA), AHA after 20 h of fasting (AHAF), and MHA after 20 h of fasting (MHAF). Four ruminally and duodenally fistulated heifers (279 +/- 99 kg of BW) individually strip-grazed wheat pastures in a Latin-square design. Eating, rumination, and idling behavior were recorded every 2 min, and bite and eating step rates were measured hourly while the heifers were grazing (11 h MHA and AHA; 4 h MHAF and AHAF). Ruminal DM pools were measured 4 times daily (0800, 1200, 1500, and 1900 h) to estimate daily herbage DMI and its pattern. Ruminal fluid was sampled at these same times and also at 2300 h. Duodenal digesta was sampled over 2 d to determine the site of herbage digestibility. Treatments did not affect daily herbage DMI (16.5 g/ kg of BW, SE = 0.0025; P > 0.05). However, they altered the eating pattern; the evening grazing bout of AHA and AHAF was greater (P < 0.05) and more intense (P < 0.05 for bite mass and rate, eating step, and intake rates). Ruminal nonglucogenic:glucogenic VFA ratio and pH were lower (P < 0.05) for AHA and AHAF during the evening. The flow of OM, N, microbial protein, and nonmicrobial OM to the duodenum did not vary (P > 0.05) among MHA, MHAF, and AHAF; however, it averaged 970, 40, 300, and 540 g/d, respectively, greater (P < 0.05) for AHA. Total tract digestibility did not differ (P > 0.05) for MHA, AHA, and AHAF, but was lower for MHAF (P < 0.05). Apparent ruminal digestion did not differ (P > 0.05) within fasted and nonfasted treatments; however, it was greater (P < 0.05) for fasted than nonfasted treatments. True OM ruminally digested did not differ (P > 0.05) among MHA, MHAF, and AHAF, but was greater (P < 0.05) for AHA. The results demonstrate the strong link between ingestion and digestion patterns, and its impact on nutrient supply. At the same amount of resource allocation, nutrient supply to grazing cattle can be modified through strategic grazing management.
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Affiliation(s)
- P Gregorini
- Southwest Research and Extensions Center, Division of Agriculture, University of Arkansas, Hope 71801, USA
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Krause KM, Combs DK, Beauchemin KA. Effects of increasing levels of refined cornstarch in the diet of lactating dairy cows on performance and ruminal pH. J Dairy Sci 2003; 86:1341-53. [PMID: 12741560 DOI: 10.3168/jds.s0022-0302(03)73719-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Our study investigated the effect of a linear increase in level of ruminally fermentable carbohydrate, at a constant level of dietary starch and fiber, on performance, microbial N yield, chewing activity, and ruminal pH of midlactation dairy cows. Eight cows (53 DIM) were assigned to four treatments in a double 4 x 4 Latin square. Diets consisted of increasing levels of refined cornstarch (0, 5.9, 11.9, and 17.9% of diet dry matter) replacing dry cracked, shelled corn so that increasing amounts of dietary starch originated from refined cornstarch. Corn gluten feed was used to balance diets for similar NDF content. The four diets averaged 17.9% CP, 27.2% NDF, 18.7% ADF, and 31.1% starch (dry matter basis). Diets were fed for ad libitum intake and had a forage to concentrate ratio of 40:60. Forage was coarsely chopped (13.7 mm mean particle size) alfalfa silage. Daily dry matter intake averaged 26.0 kg and tended (P = 0.08) to increase quadratically with increasing level of refined cornstarch. Milk production averaged 38.9 kg/d and milk fat percentage tended (P = 0.08) to decrease linearly, whereas percentage of protein increased quadratically, with increasing level of refined cornstarch. Yield of components and energy corrected milk was similar across diets. Total tract digestibility of starch increased linearly from 85.1% to 92.4% with increasing level of refined cornstarch. Microbial yield was unaffected by diet and averaged 371.1 g N/d. Time spent eating decreased linearly from 329 to 308 min/d when level of refined cornstarch was increased, but rumination time was unaffected. Ruminal concentration and proportion of acetate decreased linearly while concentration and proportion of propionate increased linearly with increasing level of refined cornstarch. Mean ruminal pH, time spent below pH 5.8 (h), and area below pH 5.8 (h x pH units/d) were unaffected by level of refined cornstarch and averaged 5.97, 8.4, and 2.9, respectively. Increasing the level of carbohydrates fermented in the rumen by replacing dry cracked corn with refined cornstarch (up to 57% of dietary starch) did not compromise rumen fermentation or affect performance of midlactation dairy cows.
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Affiliation(s)
- K M Krause
- Department of Dairy Science, University of Wisconsin, Madison 53706, USA
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10
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Rigout S, Lemosquet S, van Eys JE, Blum JW, Rulquin H. Duodenal glucose increases glucose fluxes and lactose synthesis in grass silage-fed dairy cows. J Dairy Sci 2002; 85:595-606. [PMID: 11949864 DOI: 10.3168/jds.s0022-0302(02)74113-1] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The effect of intestinal glucose supply on whole body rate of glucose appearance (WBGRa) and mammary utilization of glucose was studied in four lactating dairy cows. Glucose (0, 443, 963 and 2398 g/d) was continuously infused in the duodenum over 14-d periods using a Latin square design. A grass silage-based diet was formulated so that treatments were isoenergetic and isonitrogenous and contained 100 and 110% of energy and protein requirements according to INRA (1989). The WBGRa was measured by the [6,6-(2)H2]glucose dilution technique, and mammary glucose balance by arteriovenous differences and blood flow measurements. Duodenal glucose infusion increased arterial glucose concentrations linearly, whereas arterial concentrations of insulin, growth hormone, and glucagon were not changed. The WBGRa increased linearly with increasing glucose loads. The increase represented 42% of the intestinal glucose supplement. Mammary blood flow dramatically increased (up to 45%) and was associated with a significant increase of arterial insulin-like growth factor-1 concentrations. Mammary gland rate of glucose disappearance ([6,6-(2)H2]glucose measurement) increased linearly, whereas net mammary balance of glucose, lactose, and milk yields increased quadratically. Net mammary balance of glucose accounted for 60% of WBGRa, except for the greatest dose (47.6%). The decrease in milk yield with 2398 g/d of glucose may be explained by an imbalance in intracellular intermediate concentrations. The milk ratio of glucose-1-phosphate to glucose-6-phosphate decreased significantly at the greatest infusion of glucose. In conclusion, exogenous glucose supply to a grass silage-based diet increased WBGRa, mammary utilization of glucose and milk synthesis.
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Affiliation(s)
- S Rigout
- Unité Mixte de Recherches Production du Lait, Institut National de Recherche Agronomique, Saint-Gilles, France.
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11
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Hristov AN, Huhtanen P, Rode LM, Acharya SN, McAllister TA. Comparison of the ruminal metabolism of nitrogen from 15N-labeled alfalfa preserved as hay or as silage. J Dairy Sci 2001; 84:2738-50. [PMID: 11814030 DOI: 10.3168/jds.s0022-0302(01)74728-5] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Alfalfa (Medicago sativa L. cv. AC Blue J) was labeled with 15N during growth in a greenhouse, harvested at early bloom, and preserved as silage (19% dry matter) or as sun-cured hay. The labeled silage and hay were given as single-pulse doses to two lactating Holstein cows fed diets comprising 30% concentrate and 70% alfalfa forage (preserved either as silage or as hay). Labeled forage and ruminal content samples collected for 72 h after dosing were partitioned into N fractions and analyzed for 15N-enrichment. Pool sizes of N compartments and kinetics in the rumen were derived by isotope dilution and by gravimetric measurements. The rate of outflow of total N, determined gravimetrically, was 21% higher with the silage diet than with the hay diet. On both diets, the largest individual flux was associated with the nonprotein, nonammonia, nonmicrobial nitrogen (NPAM-N) pool. As related to the flux of 15N through the acid detergent insoluble N pool, less tracer passed through the solid-phase nonfiber N and the soluble protein-N pools, and more passed through the NPAM-N pool, with silage than with hay. The solid-phase nonfiber N pool, which includes readily available feed N and adherent bacterial- and protozoal-N, constituted the largest N entity in the rumen, followed by the NPAM-N pool. When the forage component of the diet was alfalfa silage, N flux through the NPAM-N pool was remarkably high, and with both methods of preserving alfalfa forage, the exchange of tracer was most intensive through this pool.
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Affiliation(s)
- A N Hristov
- Research Centre, Agriculture and Agri-Food Canada, Lethbridge, AB.
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Hurtaud C, Lemosquet S, Rulquin H. Effect of graded duodenal infusions of glucose on yield and composition of milk from dairy cows. 2. Diets based on grass silage. J Dairy Sci 2000; 83:2952-62. [PMID: 11132867 DOI: 10.3168/jds.s0022-0302(00)75195-2] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We conducted two trials to study the effect of graded amounts of glucose infused into the duodenum on milk yield and composition as well as on plasma metabolites, using diets based on grass silage. In trial 1, four fistulated Holstein cows were arranged in a 4 x 4 Latin square design and received 0, 750, 1500, and 2250 g of glucose/d in the duodenum. In trial 2, five fistulated Holstein cows were arranged in a 5 x 5 Latin square design and received 0, 250, 500, 1000, and 2000 g/d of glucose. In both trials, cows were fed a basal diet of 38% grass silage, 10% dehydrated alfalfa, 49% energy concentrate, and 3% oil meal. The treatments (feed plus infusion) were isoenergetic and isonitrogenous. Increased amounts of glucose increased milk yield up to 2.4 and 1.6 kg/d in trials 1 and 2, respectively. Lactose content was not affected, while fat yield and content decreased linearly. The decrease in milk fat resulted from a reduced yield of C18, probably caused by a lower mobilization of fat. The glucose treatments significantly affected the profiles of medium-chain fatty acids, by enhancing the elongation process (up to C14). Glucose infusions induced an asymptotic response of protein yield (linear increase up to 1000 g of glucose, after ceiling). It appears that with poor postruminal starch diets, such as grass silage-based diets containing 35 to 40% of concentrate, the glucose supply to the mammary gland may be limiting for milk synthesis.
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Affiliation(s)
- C Hurtaud
- Unité Mixte de Recherches Production du Lait, Institut National de la Recherche Agronomique, Saint-Gilles, France.
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García SC, Santini FJ, Elizalde JC. Sites of digestion and bacterial protein synthesis in dairy heifers fed fresh oats with or without corn or barley grain. J Dairy Sci 2000; 83:746-55. [PMID: 10791791 DOI: 10.3168/jds.s0022-0302(00)74937-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Six Holstein-Friesian heifers fitted with ruminal, duodenal, and ileal cannulas were used in a replicated 3x3 Latin square to study the effects of partial replacement [1:1 dry matter (DM) basis] of fresh winter oats (WO) by ground corn (C) or barley (B) on digestion and bacterial protein synthesis. Supplemented diets contained 24% starch, and all diets were fed indoors at 2.5% of body weight (DM basis). Ruminal and total tract digestibilities of organic matter and neutral detergent fiber were similar for all treatments. Ruminal and total tract starch digestibility was similar for C and B diets. Nitrogen intake was greater for WO than for supplemented diets. However, duodenal flows of nonammonia N and bacterial N did not differ among treatments. The efficiency of bacterial protein synthesis was similar for the three diets, suggesting that the fermentation of high quality fresh forage DM provided sufficient energy for the microorganisms in the rumen. Ruminal ammonia-N concentration was greater for WO than for supplemented diets, and for C than for B diet. Ruminal fluid pH and concentrations of total volatile fatty acid were not different among diets, but concentration of acetate was higher and that of propionate was lower for WO than for supplemented diets and for C than for B diet. Supplementation of WO with barley rather than with corn decreased C2:C3 ratio without affecting fiber digestion. Supplements increased N utilization relative to N intake but did not increase duodenal nonammonia N flow.
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Affiliation(s)
- S C García
- Departamento de Producción Animal, Instituto Nacional de Technología Agropecuaria, Balcarce, Provincia de Buenos Aires, Argentina.
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Cone JW, Van Gelder AH, Soliman IA, De Visser H, Van Vuuren AM. Different techniques to study rumen fermentation characteristics of maturing grass and grass silage. J Dairy Sci 1999; 82:957-66. [PMID: 10342234 DOI: 10.3168/jds.s0022-0302(99)75315-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Grass samples were harvested during the 1993 growing season after a precut on April 27, 1993 and were stored frozen or left to ensile in 30-L buckets. Effects on chemical composition and fermentation kinetics of the maturation of the grass and of ensiling were investigated. Chemical composition and fermentation kinetics were determined using the gas production technique, in vitro techniques, and the nylon bag technique. Two silage samples were also investigated in vivo. Maturation caused a decrease in crude protein content and organic matter degradability and an increase in neutral detergent fiber, acid detergent fiber, and lignin contents. Degradation rates were highest for the youngest samples and decreased as grass and silage matured. This result could be observed from the first derivative of the cumulative gas production curves (i.e., the rate of gas production) and from the gas production parameters. The rate of degradation of the nonsoluble fraction of the young samples, determined using the gas production technique, was relatively higher in rumen fluid from a cow fed silage from grass cut at a young stage. More mature samples were degraded relatively faster in rumen fluid from a cow fed mature grass silage, suggesting a specific adaptation of the rumen microorganisms to the grass properties. There was a good relationship among the second phase of gas production (i.e., fermentation of the nonsoluble fraction), maturity of the grass and grass silage samples, degradability determined with the Tilley and Terry technique, and degradability determined after 46 h of incubation in rumen fluid. Results obtained with both of the different in vitro techniques and the nylon bag technique were confirmed by the in vivo experiments involving the two silage samples.
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Affiliation(s)
- J W Cone
- Agricultural Research Department, Institute for Animal Science and Health (ID-DLO), Lelystad, The Netherlands
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