COSER, A. C.

DERESZ, F.

VERNEQUE, R. da S.

English

Repository Open Access to Scientific Information from Embrapa

ID # 19-02EFFECT OF CONCENTRATE SUPPLEMENTATION ON MILK YIELD OFCROSSBRED HOLSTEIN X ZEBU COWS GRAZING ELEPHANTGRASSFermino Deresz1, Antonio Carlos Cóser1, Rui da Silva Verneque11Embrapa - National Dairy Cattle Research Center - Rua Eugênio do Nascimento, 610Juiz de Fora, MG, Brasil. CNPq fellowship.AbstractThe study was carried out using 12 ha of Elephantgrass (Pennisetumpurpureum Schum.) pasture, fertilized with 660 kg/ha/year of 20.05.20 formula,during the rainy season of 1999. It was used eight cows per treatment/site in acompletely randomized block design. Blocks were based on milk yield and date ofcalving. Pasture was managed with 30 days of resting period using a stocking rate offive cows/ha. The objective of the study was to evaluate the effects of feedingconcentrate for the first 60 (T60) or 120 days (T120) post-partum on milk yield, inrelation to the control-group (T0), fed no concentrate. Concentrate was fed at a rate of1 kg per each 2 kg of milk above the basal level of 10 kg (rainy season) or 12kg/cow/day (dry-season). It was planned to have half of the cows calving on thebeginning of the dry season and half on the beginning of the rainy season. The studystarted in February in site one and in site two in March. Corn silage supplementationstarted on April 15 (site one) and May 14 (site two) and was halted on November 23in both sites. After the afternoon milking, the cows had access to paddocks. The datawere analyzed separately for the two seasons. There was no treatment effect on milkyield (P>0.05) for any season and the average dry season milk yield was 12.2, 12.8,13.3, for the T0, T60 and T120 treatments, respectively.Keywords: concentrate supplementation, Elephantgrass, dairy cows, milk yield,rotational grazing.IntroductionThere is information in the literature, indicating that it is possible to obtainaverage daily milk yield of 12 to 14 kg of crossbred Holstein x Zebu cows during therainy season, on Elephantgrass (Pennisetum purpureum Schum.) pasture, rotationallygrazed with 30 days of resting period and three days paddock occupation, withoutconcentrate supplementation (Deresz et al., 1994). However, when the cows weresupplemented with 2 kg of concentrate per cow per day, the milk response was onaverage 0,55 kg for each kg of concentrate offered during the rainy season onfertilized Elephantgrass pasture. Similar results have been observed by Alvim et al.(1997) working with purebred Holstein cows grazing coast-cross (Cynodon dactylon(L.) Pers.) fertilized pasture with a variable stocking rate and rotationally managedwith one day paddock occupation and around 30 days resting period. However, thecost of 1 kg of concentrate under Brazilian conditions is usually higher than 1 kg ofmilk and so the concentrate supplement is not economically viable.Considering the importance of these factors and their relationship with milkcost, different strategies of concentrate supplementation were proposed to evaluate theeffects under grazing conditions using crossbred Holstein x Zebu cows.Material and MethodsThe study was carried out at Embrapa - National Dairy Cattle Research Centerin Brazil, using 12 ha of Elephantgrass (Pennisetum purpureum Schum.) pasture intwo different sites with six ha each. The pasture was fertilized with 660 kg/ha/year of20.05.20 formula, applied half in January and half in March of 1999. It was used eightcrossbred Holstein x Zebu cows per treatment/site in a completely randomized blockdesign. The blocks were based on milk yield and date of calving. The potential milkyield per cow was around 3,500 kg/lactation. The pasture was rotationally managedwith 30 days of resting period and three days of paddock occupation using a stockingrate of five cows/ha. The objective of the study was to evaluate the effects of feedingconcentrate for the first 60 (T60) or 120 days (T120) post-partum on milk yield, inrelation to the control-group (T0), fed no concentrate. Concentrate was fed at a rate of1 kg per each 2 kg of milk above the basal level of 10 kg (rainy season) or 12kg/cow/day (dry-season). It was planned to have half of the cows calving (pregnantcows) on the beginning of the dry season and half on the beginning of the rainyseason. The study started in February in site one and in site two in March. During thepre-partum period (60 days) all the cows remained in the treatments with noconcentrate supplementation, following the treatments, observing the seasonsdifferences (dry season silage) to evaluate the residual treatment effects. Corn silagesupplementation started on April 15 (site one) and May 14 (site two) and was haltedon November 23 in both sites. After the afternoon milking, the cows had access topaddocks. Corn silage was offered ad libitum during the morning and the afternoonmilking times. During the dry-season all the cows were fed 1 kg/cow/day of soybeanmeal to correct the crude protein of corn silage of 7-8% to 12-13% on a dry matterbasis. The cows were milked twice a day in a milking machine and the data dailyrecorded. The data were analyzed separately for the two seasons.Results and DiscussionAverage milk yield in both seasons are presented on Table 1. There was notreatment differences (P>0.05) in milk yield. However, average milk yield was higherduring the dry than during the rainy season (P<0.05). The lower milk productionduring the rainy season were apparently due to the fact that half of the cows werepregnant and on the third stage of lactation and half of them were pregnant andexpected  to calve on November or December (rainy season) and  above 120 days oflactation. Deresz et al. (1994) observed average milk yield of 12 to 14 kg/cow/day onfertilized Elephantgrass pasture rotationally managed during the rainy season, withoutconcentrate supplementation with a stocking rate of five cows/ha.The average corn silage chemical composition was 30.3% DM, 7.1% CP, 44%NDF and 62.3% IVDMD.In the dry season the average milk yield were higher then during the rainyseason apparently due to the fact that half of the cows were fresh in milk and receivingconcentrate supplementation (T60 and T120) if the milk yield  were above 12kg/cow/day.. However, there was no significant difference (P>0.05) betweentreatments, mainly because of the high coefficient of variation (34%).Overall average milk yield for both seasons are shown on Figure 1. Notice thatthe rainy season correspond to the first 15 weeks and also that the cows withoutconcentrate supplementation (T0), during the dry season, produced on average 12.2kg/cow/day (Figure 1).In conclusion, there was no effect on milk yield due to the different strategiesof concentrate supplementation in both seasons under the conditions of this study.ReferencesAlvim, M.J., Vilela D., Lopes R.S. (1997). Efeitos de dois níveis de concentrado sobrea produção de leite de vacas da raça Holandesa em pastagem de coast-cross (Cynodondactylon (L.) Pers). Rev. Bras. Zootec., 26:967-975.Deresz, F , Cóser A. C., Martins, C. E. et al. (1994). Utilização do capim-elefante(Pennisetum purpureum Schum.) para a produção de leite. In: Simpósio Brasileiro DeForrageiras e Pastagens, 1994, Campinas. Anais... Campinas:CBNA, p.183-199.Table 1 - Average milk yield (kg/cow/day) of crossbred cows grazing Elephantgrassand fed concentrate for the first 60 (T60) or 120 days (T120) of lactation, during therainy and dry seasons.SeasonsTreatmentsRainy DryT0 9.0  0.9 12.2  0.9T60 8.6  0.9 12.8  0.9T120 9.2  1.1 13.3  1.15678910111213141516171 4 7 10 13 16 19 22 25 28 31 34 37 40 43WeeksMilk yield (kg/cow/day)T0 T60 T120Figure 1 - Average milk yield (kg/cow/day) of crossbred cows grazingElephantgrass and fed concentrate for the first 60 (T60) or 120 days(T120) of lactation, during the rainy and dry seasons.

Effect of concentrate supplementation on milk yield of crossbred Holstein x Zebu cows grazing elephantgrass.

http://www.alice.cnptia.embrapa.br/bitstream/doc/1165382/1/Effect-of-concentrate-supplementation-on-milk-yield-of-crossbred.pdf

Effect of concentrate supplementation on milk yield of crossbred Holstein x Zebu cows grazing elephantgrass.

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