Dry matter intake (DMI) of coast-cross grazing by crossbred Holstein-Zebu and Zebu lactating cows was calculated using in vitro dry matter digestibility from extrusa (four esophageal fistulated cows) and fecal output estimate with mordent chromium. Pasture was rotationally grazed with three days grazing period and 27 days resting period, adopting a stocking rate of 1.6 and 3.2 cows/ha, during the dry and rainy season respectively. Voluntary DMI was estimated from degradation characteristics using different equations. Predicted coast-cross DMI varied with models. The prediction of tropical forages dry matter intake from equations based in ruminal degradation parameters needs further investigation before being employed in practice

Aroeira, L. J. M.

Berchielli, T. T.

da Silveira, R. N.

Furlan, C. L.

Malheiros, E. B.

Salman, A. K. D.

Soares, J. P. G.

English

University of Kentucky

University of Kentucky UKnowledge International Grassland Congress Proceedings XIX International Grassland Congress Prediction of Dry Matter Intake Based on Ruminal Degradation from Milking Cows Grazing Coast-Cross Grass T. T. Berchielli Universidade Estadual Paulista, Brazil J. P. G. Soares Universidade Estadual Paulista, Brazil L. J. M. Aroeira EMBRAPA, Brazil C. L. Furlan Universidade Estadual Paulista, Brazil A. K. D. Salman Universidade Estadual Paulista, Brazil See next page for additional authors Follow this and additional works at: https://uknowledge.uky.edu/igc  Part of the Plant Sciences Commons, and the Soil Science Commons This document is available at https://uknowledge.uky.edu/igc/19/9/26 This collection is currently under construction. The XIX International Grassland Congress took place in São Pedro, São Paulo, Brazil from February 11 through February 21, 2001. Proceedings published by Fundacao de Estudos Agrarios Luiz de Queiroz This Event is brought to you for free and open access by the Plant and Soil Sciences at UKnowledge. It has been accepted for inclusion in International Grassland Congress Proceedings by an authorized administrator of UKnowledge. For more information, please contact UKnowledge@lsv.uky.edu. Presenter Information T. T. Berchielli, J. P. G. Soares, L. J. M. Aroeira, C. L. Furlan, A. K. D. Salman, R. N. da Silveira, and E. B. Malheiros This event is available at UKnowledge: https://uknowledge.uky.edu/igc/19/9/26 ID # 09-31PREDICTION OF DRY MATTER INTAKE BASED ON RUMINAL DEGRADATIONFROM MILKING COWS GRAZING COAST-CROSS GRASS1T.T. Berchielli 2,4, J.P.G. Soares2, L.J.M. Aroeira3, C.L. Furlan 2, A.K.D. Salman2 , R.N. daSilveira2 and E.B. Malheiros21Financial support from FAPESP2UNESP-FCAV- C.P. 188, Jaboticabal, SP, Brasil, 14870-0003EMBRAPA-CNPGC - R.Eugênio do Nascimento, 610 -  Juiz de Fora, MG, Brasil36038-330, CNPq scholarship.AbstractDry matter intake (DMI) of coast-cross grazing by crossbred Holstein-Zebu and Zebulactating cows was calculated using in vitro dry matter digestibility from extrusa (fouresophageal fistulated cows) and fecal output estimate with mordent chromium. Pasture wasrotationally grazed with three days grazing period and 27 days resting period, adopting astocking rate of 1.6 and 3.2 cows/ha, during the dry and rainy season respectively. VoluntaryDMI was estimated from degradation characteristics using different equations. Predictedcoast-cross DMI varied with models. The prediction of tropical forages dry matter intake fromequations based in ruminal degradation parameters needs further investigation before beingemployed in practice.Keywords: degradability, dry matter intake, grazing, lactating cows, prediction equationsIntroductionDue to the difficulty in making direct determinations of DMI of grazing animals anumber of indirect methods have been evolved. always considering digestibility of dry matterintake and fecal output. Indirectly. fecal output can be determined based on the ratio betweenthe quantity of a marker dosed to an animal and its concentration in the feces. In contrast todaily dosing a marker (mordent chromium) may be administered once to an animal followedby frequent fecal collections in order to characterize the “pulse” in marker concentrationfound in the feces (Pond et al. 1989).The in situ bag technique was evaluated as a method of predicting the voluntary intakeand digestibility of forage by several authors Von Keyserlingh & Mathinson (1989).The goal of this trial was compare the dry matter intake of coast-cross grazed bycrossbred and zebu lactating cows. estimated with the model suggested by Pond et al. (1989)and different equations predicting the dry matter intake as proposed by Von Keyserlingk &Mathinson (1989); ∅rskov et al. (1988); Shem et al. (1995) and Madsen et al. (1997).Material and Methods The trial was carried out at Experimental Station of Ribeirão Preto, São Paulo, StateBrazil. The evaluations were done twice from June to November 1996 and twice from Januaryto April. 1997. Lactating crossbred (8) and zebu (8) multiparous cows between 30 and 90days in milk. with an average body live weight of 490 and 422 kg respectively were used. Theexperimental design adopted was a randomized blocks with two treatments  (crossbred andzebu cows) eight repetitions and four times. During the experimental period cows grazed coast-cross (Cynodon dactylon (L) Pers).pasture managed in a rotational system with three days grazing and 27-days resting period.Stocking rate was 1.6 cows/ha from June to November and 3.2 cows /ha from January toApril. All the cows were supplemented with 3 kg of concentrate and received mineral salts adlibtum. For the DMI estimations were adopted the indirect method using the in vitro drymatter digestibility (IVDMD) from extrusa collected from four esophageal canulated cows(two crossbred and two zebu cows) and the fecal output calculated by the administration of apulse dose of neutral detergent fiber (NDF) of the extrusa marked with mordent chromium(Colucci et al.. 1984) as described by Pond et al. (1989). The fecal collection was done by grab samples during six days after the pulse dose ofmordent chromium. The chromium was analyzed by spectrophotometry following theWillians et al. (1962) recommendations. The fecal output was calculated using the excretioncurves proposed by the one compartment model time dependent described by POND et al.(1989). This model allows the estimation of fecal output rumen and pos-rumen rate ofpassage. and dry matter intake. The in situ degradability was performed at the end of each collection time. using threenon-lactating crossbred cows. adapted to the coast-cross pasture. receiving the sameconcentrate in the same amount of the tested cows.  The nylon bags were incubated with 5 gof owen dry material. originated from extrusa. at different times (3. 6. 12. 24. 48. 72. 96 h).The DMI predictions were calculated by the degradations parameter (Mehrez & ∅rskov,1977). where “a” is the soluble material. “b” the potential degradable material and “c” the rateof degradation of “b”. The equations tested were proposed by Von Keyserlingk & Mathinson(1989). where: DMI = -1.19 + 0.035 (a+b) + 28.5c.  ∅rskov et al. (1988). where: DMI = -0.822 + 0.0748 (a+b) + 40.7c. SHEM et al. (1995). where:  DMI = -8.286 + 0.266a + 0.102b+17.696c and Madsen et al. (1997). Madsen et al. (1997) developed a method where the rate degradation in the rumen iscombined with the rate of the outflow to give an estimate of the fill of the feeds. The potentialintake of the feeds is described by their physical fill with the unit day. The capacity of ananimal to eat the feed has the unit kg. The intake is then predicted by dividing the capacity ofthe animal with the fill of the feeds giving the unit kg/day -1. Them fill is calculated by theformula: FILL = [(1-a-b) / k + (c + k)]/24 being “k” the fractional rate of passage (h-1). Thepotential daily NDF intake of feedstuff ascribed to a limitation of the physical capacity of thereticulo-rumen can then be calculated as: FINDF (kg/day –1) = Rumen capacity (kg NDF) / fill(days) and the potential dry matter (DM) intake (FIDM) of a feedstuff can then be calculatedas: (FIDM) = 1 / Proportion of NDF in the feedsuff DM x FINDF. For the NDF intake wasconsidered the rumen capacity as 1.2 % of the cows live body weight as proposed by Mertens(1987).The differences among the average DMI estimated with mordent chromium and thedifferent equations were analyzed using Tukey test 5%. Utilizing ANOVA program fromSAS. 1990.Results and DiscussionThe results obtained with the in situ incubation are shown in Table 1. No difference(P>.05) was found among any variable estimated. in relation to the time of the samplecollection. The data of effective DM degradability (DE) calculated from the formula proposedby Orskov & McDonald (1979) varied from 40.2 to 48.3. respectively. in November. 1996and April. 1997. These values were similar to the (45.5%). reported by Aroeira et al. (1996).and higher than (33.3%) that observed by Berchielli et al. (1996). working with coast-crosshay.The mean total DMI. considering the concentrate fed (3.0kg /cow/day). was 6.7kg/cow/day or 1.5 % of live body weigh (BW) and DMI originated from the coast-cross grass.both estimated with the model described by Pond et al. (1989) were 4.7 kg/cow/day  or 1% ofBW for crossbred cows. with a milk production of 10.6 kg/kg/day and 2.7 kg/cow/day or .7%of BW for zebu cows with a milk production of 6.4 kg/cow/day. Those data resulted from thepasture DMI were lower than that (2.5% BW) reported by Marrero et al. (1989) workingheifers and much lower than 8.5 kg/cow/day as described by Milena et al (1987) with cowsproducing 10 kg of milk per day without any concentrate supplementation.The data obtained from the equations of prediction are shown in table 2. All the DMIpredictions from coast-cross grass overestimated the pasture intake. However. it should bementioned. that those equations were based on the potential of the rumen degradation of theforage and did not considered any influence of the substitution rate caused by the ingestion ofthe concentrate. The DMI estimated as calculated by Orskov et al (1988) was 5.5 kg was thelowest one (P<.05) followed by the 7.7 kg as suggested by Madsen et al. (1997) and thesimilar values of 12.2 and 12.7 kg/cow/day as proposed by Von Keyserlingk & Mathison(1989) and Shem et al. (1995) respectively.The prediction of dry matter intake from cows grazed tropical grass need to be morestudied in longer trials with a large number of animals. preferentially maintained in anexclusively grazing system.ReferencesAroeira L.J.M. (1997). Intake estimations of tropical forages. In: Simpósio Internacionalde Digestibilidade em Ruminantes. 1997. Lavras. MG. Anais... Lavras: UFLA-FAEPE.p.127-163.Berchielli, T.T., Figueira D.G. and Rodriguez N.M. (1996). “In situ” dry matterdegradability with differents concentrated levels on diet. In: Reunião Anual da SociedadeBrasileira de Zootecnia, 33, 1996, Fortaleza-CE. Anais... Fortaleza: SBZ 3: 39-40.Madsen. J. and Havelplund. T. (1997). Prediction of in situ protein degradability in therumen. Results of European ring test. Liv. Produc. Sci., 39:201-212.Marrero, E.D., Ruiz R. and Ruiz T.E. et al. (1989. Systemas de alimentacion engramineas y leguminosas para hembras bovinas de reenplazo. 2. Conducta en pastoreoPaturages et alimenttion des ruminants en zone tropicale humide. p. 401-410.Mehrez. A.Z. and ∅rskov E.R. (1977). A study of the artificial fiber bag techinic fordetermining the digestibility of feed in the rumen. J. Agric. Sci., 88:645-650.Mertens, D.R. (1987). Predicting intake and digestibility using mathematical models ofruminal function. J. Anim. Sci., 64: 1548-1558.Miilera, M., Martinez J. and Caceres O. et al. (1987. Efecto de diferentes ofertas delpasto Cynodon dactylon L. Pers. CV Coast Cross.1-Sobre la estrutura y valor nutritivo dela planta em pastoreo. Pastos y Forrages. , 10: 239-245∅rskov, E.R.. Reid G.W. and Kay M. (1988). Predicting of intake by cattle fromdegradation characteristics of roughages. Anim. Produc., 46: 29-34.Ørskov, E.R. and McDonald I. (1979). The estimation of protein degradability in therumen from incubation measurements weighted according to rate of passage. J. Agric. Sci.,92:499-503.Pond, K. P. et al. (1989). Passage of chromium-mordanted and rare earth-labeled fiber:time of dosing kinetics. J. Anim. Sci., 27:1020-1028.Shem, M.N., Ørskov E.R. and Kimambo A.E. (1995). Prediction of voluntary dry-matter intake. digestible dry-matter intake and growth rate of cattle from degradationcharacteristics. J. Anim. Sci., 60: 65-74.Von Keyserlingk, M.A.G. and Mathison G.W. (1989). Use of the in situ technique andpassage rate constants in predicting voluntary intake and apparent digestibity of forragesby steers. Can. J. Anim. Sci., 69: 973-987.Table 1 - Degradability parameters of DM: “a” soluble dry matter, “b” potential degradabledry matter, “c” rate of degradation from “b”, “k” ruminal rate of passage  and effectivedegradability “DE”.DM degradability parameterMonth a (%) b (%) c (% /h) K (%/h) DE (%)June 75.5 63.5 2.17 1.8 47.3November 62.8 52.4 1.78 1.5 40.2January 56.4 62.6 3.97 2.1 41.1April 61.9 43.1 3.63 1.4 48.3Table 2 - Mean DMI from cost-cross estimated by the model of Pond and predicted bydifferent equations as kg/cow/day and as percentage of live body weight (% of BW)MODEL kg/day % of BWMadsen   7.76  b 1.70  bVon Keyserlingk 12.18  a 2.66  aShem 12.74  a 2.79  aOrskov    5.49  c 1.19  cPond    3.69  d 0.80  dCV (%)                   13.07                    9.18Data followed by different letters in the column are different (P<.05) by Tukey test.

Prediction of Dry Matter Intake Based on Ruminal Degradation from Milking Cows Grazing Coast-Cross Grass

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Prediction of Dry Matter Intake Based on Ruminal Degradation from Milking Cows Grazing Coast-Cross Grass

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