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Livestock Science 120

Effects of early weaning and breed on calf performance and carcassand meat quality in autumn-born bull calves

M. Blanco a,⁎, D. Villalba b, G. Ripoll a, H. Sauerwein c, I. Casasús a

a Unidad de Tecnología en Producción Animal, Centro de Investigación y Tecnología Agroalimentaria,Gobierno de Aragón. Avda. Montañana 930. 50059 Zaragoza, Spain

b Departament de Producció Animal, Universitat de Lleida. Avda. Rovira Roure 191. 25198 Lleida, Spainc Institute of Animal Science; Physiology and Hygiene Unit, University of Bonn, Katzenburgweg 7-9, 53115 Bonn, Germany

Received 8 October 2007; received in revised form 15 February 2008; accepted 2 May 2008

Abstract

This study assessed the effects of age at weaning (early weaning at 90 d or traditional weaning at 150 d) and breed (Parda deMontaña or Pirenaica) on calf performance and carcass and meat quality in autumn-calving beef cattle. At calving, 14 Parda deMontaña and 14 Pirenaica cow–calf pairs were randomly assigned to one of two weaning treatments, and kept indoors duringlactation. After weaning, calves were fed an intensive diet until slaughter at 450 kg. The interaction between age at weaning andbreed was not significant for any of the parameters studied. From 90 d to 150 d, early weaned calves had greater ADG (P=0.001)and IGF-I concentrations (P=0.001) than traditionally weaned calves, but their leptin concentrations were similar (P=0.15).During the finishing phase, performance, daily feed intake, and efficiency did not differ between treatments. Early weaning did notaffect age at slaughter, carcass weight, fatness score, fat colour, and meat quality, but improved carcass conformation (P=0.04).Early weaned calves had greater total DMI (P=0.002) with greater concomitant feed costs (P=0.001) and yielded a slightly greaterincome than traditionally weaned calves; therefore, economic margins did not differ. Parda de Montaña calves tended to havegreater ADG from birth to 90 d and were heavier at 90 d (P=0.01) than were Pirenaica calves. From 90 d to 150 d, performanceand IGF-I and leptin concentrations did not differ between breeds; thus, Parda de Montaña calves remained heavier at 150 d.During the finishing phase, at times, weight gains of Parda de Montaña and Pirenaica calves differed, but the overall performance,feed intake, and efficiency of the two breeds were similar. Pirenaica calves had heavier carcasses (P=0.04) with greaterconformation scores (P=0.04) than Parda de Montaña calves; thus, income per carcass was greater for the former than the latter(P=0.007). As feed costs were similar for both breeds, the economic margin of Pirenaica calves was greater than that of Parda deMontaña calves (P=0.01). In conclusion, in both breeds weaning strategies had similar effects on performance and carcass andmeat quality; however, from an economic point of view, and considering only the costs associated with the calf, raising Pirenaicacalves would be more profitable, at either age at weaning.© 2008 Elsevier B.V. All rights reserved.

Keywords: Age at weaning; Breed; Performance; Carcass quality; Meat quality; Beef cattle

⁎ Corresponding author. Tel.: +34 976 713221; fax: +34 976 716335.E-mail address: mblanco@aragon.es (M. Blanco).

1871-1413/$ - see front matter © 2008 Elsevier B.V. All rights reserved.doi:10.1016/j.livsci.2008.05.003

1. Introduction

To guarantee the sustainability of beef cattle farms indry mountain areas the use of forage resources has to be

Table 1Composition of the diets used in the experiment

Item Total mixedration a

ConcentrateA b

ConcentrateB c

Ingredients (% DM)Alfalfa hay 9.9 – –Barley straw 44 – –Ground corn – 30 32Ground barley 18.4 27.3 23.5Gluten feed 4.5 10 12Soybean meal 9.7 14 9.4Cereal by-products – 5.2 8.4Sugar beet pulp – 8 10Dry citric pulp 6.5 – –Sugarcane molasses 6 2 –Vitamins 1.0 0.5 0.5

Nutrient compositionCP, % 12.46 14.9 13.7Ash, % 8.70 5.3 5.3Crude fibre, % 24.13 5.6 6.1ADF 30.20 5.3 5.4NDF 40.29 16.3 17.2Ca, % 0.61 0.76 0.80P, % 0.35 0.87 0.78Mg, % 0.26 0.16 0.16ME, MJ/kg DM 8.61 11.47 11.65a Fed to cows during lactation.b Fed to calves from weaning to 350 kg LW.c Fed to calves from 350 kg LW to slaughter.

104 M. Blanco et al. / Livestock Science 120 (2009) 103–115

improved (Casasús et al., 2002). Early weaning mightbe a feasible alternative for a more cost-effective use offeed resources (Peterson et al., 1987). Autumn-borncalves could be early weaned in early spring while theirdams grazed in low quality forest pastures, which can beefficiently used by dry cows (Casasús et al., 2005).Weight gains of spring-born early weaned calves havebeen reported to be greater than those of their nursingcounterparts (Myers et al., 1999a) but, in the finishingphase, the performance of traditionally weaned calveswas similar to (Schoonmaker et al., 2004) or better thanthat of early weaned calves (Blanco et. al., 2008);however, calf management and performance can varywith the calving season.

In addition, the effect of early weaning on perfor-mance can be breed-dependent (Myers et al., 1999a).Parda de Montaña and Pirenaica are two of the mostcommon beef cattle breeds in the Spanish Pyrenees.Parda de Montaña breed is derived from the formerBrown Swiss and was selected for meat production, andPirenaica is a local breed. Although both breeds havesimilar mature weight (575 kg LW at calving, Casasúset al., 2002), Parda de Montaña cows have greater milkyield and consequently their calves have greater weightgains during lactation than Pirenaica ones (Sanz et al.,2003; Villalba et al., 2000). Besides, Parda de Montañais an intermediate-maturing breed whereas Pirenaica is alate-maturing breed (Piedrafita et al., 2003). Therefore,growth patterns and carcass and meat qualities of thosebreeds might respond differently to a change in weaningmanagement.

Serum IGF-I concentrations, which are influencedby feeding level, reflect the nutritional state and growthpotential of cattle (Elsasser et al., 1989). Leptin con-centrations are associated with adiposity and feed intake(Chilliard et al., 1999). Thus, a change in nutritionalmanagement caused by a change in the age at weaningmight influence IGF-I and leptin concentrations and,consequently, modify growth and development. The ob-jective of this study was to determine whether age atweaning and breed affect calf performance, IGF-I andleptin concentrations, carcass and meat quality, andeconomic performance of beef cattle.

2. Materials and methods

2.1. Animals and management

In the autumn of 2003, 28Parda deMontaña and 27 Pirenaicamultiparous cows calved at La Garcipollera Research Station, inthe central Pyrenees (Spain, 42° 37′ N, 0° 30′W; 945 m a.s.l.).Fourteen Parda de Montaña and 14 Pirenaica purebred malecalves and their dams were randomly assigned at calving to one

of two ages of calf at weaning: early weaning (mean 90±SE2.2 d postpartum) or traditional weaning (150±1.8 d post-partum), in a 2×2 factorial experiment (2 breeds×2 ages atweaning). Cow performance has been reported elsewhere(Casasús et al., 2006).

During the lactation period, cows and calves were loose-housed on a treatment basis. Parda de Montaña and Pirenaicacows were fed to meet their nutritive requirements for main-tenance and for an estimated daily milk production of 9 kg and7 kg, respectively (Sanz et al., 2003). Each day, cows weregroup-fed 12 kg (Parda de Montaña) or 11 kg DM (Pirenaica)of a total mixed ration (Table 1) per cow. Calves were allowedto suckle their dams twice daily for 30 min at 0800 h and1600 h, which is the common practice under Pyrenean farmingconditions (Sanz et al., 2004). Calves received no other feedduring lactation. Before the calves reached 3 months of age,they were vaccinated against RSV, PI3, and Mannheimia(Pasteurella) haemolytica (Bovipast RSP, Intervet, MiltonKeynes, UK), IBR (Ibraxion, Merial, Lyon, France) andChlostridium perfringens (Polibascol, Schering-Plough,Kenilworth, USA).

Early weaned calves were weaned at 90 d, transported toa feedlot to follow a commercial feeding programme atMontañana Research Station (41° 43′ N, 0° 48′W; 225 m a.s.l.),and randomly assigned to one of two pens, where theyindividually fed from ALPRO feeding stations (Alfa LavalAgri, Tumba, Sweden). At 150 d, traditionally weaned calves

105M. Blanco et al. / Livestock Science 120 (2009) 103–115

were weaned and transported to the same feedlot as their earlyweaned counterparts. Traditionally weaned calves were randomlyassigned to one of two pens equipped with individual feedingstations.

During their first week at the feedlot, calves were trained toconsume feed from individual feeding stations and receivedconcentrates in gradually increasing amounts. Thereafter,concentrates and barley straw were available ad libitum, andconcentrate composition was adjusted to animal requirementsin two phases. From weaning at either age until they reached350 kg BW, calves received finishing concentrate A; there-after and until slaughter, they received finishing concentrate B(Table 1), according to the established commercial feedingprogramme.

When calves reached 450 kg, they were slaughtered in fivebatches in different days in a commercial abattoir (MercaZar-agoza, Zaragoza, Spain) 6 km from the Research Station. Tominimize pre-slaughter stress, calves were transported on theslaughter day, kept with members of their treatment group andseparated from unfamiliar animals, and slaughtered just afterthey arrived at the abattoir. Animals were stunned usingcaptive bolt pistol and processed following standard commer-cial practices.

All of the procedures used in this study met the guidelinesof the Council Directive 86/609/EEC (European Commu-nities, 1986) on the protection of animals used for experi-mental and other scientific purposes.

2.2. Measurements

Throughout the experiment, calves were weighed weekly at0800 h (without prior deprivation of feed and water). ADGwas calculated by linear regression of weight on date for eachmonth and for the periods 0 to 90 d, 90 to 150 d, and 150 d toslaughter (finishing phase).

Milk intake was assumed to be the cow milk yield asestimated using the oxytocin and machine milking method (LeDu et al., 1979) at 90 d in all strategies and in traditionallyweaned calves also at 150 d. To analyze the chemicalcomposition of the samples from each cow and milking day,an infrared scan was used (Milkoscan 255 AB, Foss ElectricLtd., Warrington, U.K.). The results were used to calculateenergy-corrected milk (ECM) yield (adjusted to 3.5% fat and3.2% protein content). During the feedlot phase (from weaningto slaughter), concentrate intake was automatically recordeddaily on an individual basis. The results were used to deter-mine overall and monthly dry matter intake (DMI) per day,total DMI, and gain to feed ratio (G:F).

2.3. Blood sampling and hormone analyses

To determine IGF-I and leptin concentrations, blood sam-ples were obtained at 0800 h using caudal venipuncture at90 d, 150 d, and one day before slaughter. Blood samples wereallowed to clot for 24 h before the serum was frozen at −20 °C.Circulating IGF-I concentrations were quantified using acommercial EIA kit (OCTEIA IGF-I, IDS, Boldon, U.K.), and

intra- and inter-assay coefficients of variation were 3.6% and3.4%, respectively. Serum leptin concentrations were deter-mined using a competitive EIA for leptin in domestic animals(Sauerwein et al., 2004). Intra- and inter-assay coefficients ofvariation were 6.6% and 11.5%, respectively.

2.4. Slaughter and sampling procedures

After slaughter, carcasses were weighed and 2% of theweight was subtracted to estimate cold carcass weight. Dressingpercentage was calculated by dividing cold carcass weight byslaughter weight, which was obtained on the day beforeslaughter. The carcasses were chilled for 24 h at 4 °C, andthen were graded using the European Grading Systems(Directives (ECC) no. 1208/81 and no. 2237/91). Carcassconformation was evaluated using an 18-point scale (from1=poorest, to 18=best), and fatness was scored using a 15-pointscale (from 1=leanest, to 15=fattest). To measure subcutaneousfat colour (CIE L⁎ (lightness), a⁎ (redness) b⁎(yellowness)), aspectrophotometer was used (Minolta CM-2600d, KonicaMinolta Holdings, Inc, Osaka, Japan). Those results were usedto calculate hue angle values ((arctan b⁎/a⁎)×57.29) (Albertíet al., 2005).

To determine meat pH, instrumental colour, texture,chemical composition, and fatty acid composition, the lon-gissimus thoracismuscle of each left half carcass was removed(between T6 and T11), dissected, and sliced into steaks.Ultimate pH (24 h) was measured using a Crison pH meter(Crison Instruments, SA, Barcelona, Spain). Lean meat colourwas measured after 24 h of air exposure with a spectro-photometer. To quantify meat texture, steaks that had beenaged for 7 d were subjected to a Warner–Bratzler shear forcedetermination using an Instron shear machine (Model 5543,Instron Limited, Barcelona, Spain) (Honickel, 1998). Beforeassessing the chemical composition of the meat, the sampleswere freeze-dried and dry matter content was calculated.Protein content was determined following the Dumas Pro-cedure (A.O.A.C., 1995) using a Nitrogen and Protein analyser(Model NA 2100, CE Instruments, Thermoquest SA, Barce-lona, Spain). Fat content was quantified using the AnkomProcedure (AOCS Am 5-04) with an Ankom extractor (ModelXT10, Ankom Technology, Madrid, Spain). Fatty acid (FA)profiles were obtained by following the procedures of Tor et al.(2005), modified for beef meat (Blanco et al., 2008). TotalSaturated FA (SFA), Monounsaturated FA (MUFA), Poly-unsaturated FA (PUFA), and the PUFA/SFA ratios werecalculated using individual percentages of FA.

2.5. Economic analysis

The economic performance of the two calf-managementstrategies in both breeds was evaluated based on the financialitems that differed among strategies. The technical and economicaspects that differed between strategies included weaningweight, calf value at weaning, days at the feedlot, feedlotyardage costs, feed intake, feed costs, carcass weight, con-formation, and selling value of calf at slaughter. The economic

106 M. Blanco et al. / Livestock Science 120 (2009) 103–115

margin was calculated as income at slaughter minus calf value atweaning, yardage costs and feed costs. Actual selling value ofcalves at weaning, carcasses and concentrate costs in 2004 wereused in the analysis.Within the observedweight ranges, price perkg of weaned calf was constant, and price per kg of finished calfdepended on conformation score, according to the Spanish pricesystem.

2.6. Statistical analysis

Performance (weight and ADG), feed intake during thefinishing phase, IGF-I, and leptin concentrations were analyzedusing the MIXED procedure for repeated measures (SAS Inst.Inc., Cary, NC, USA). The model included time by weaningtreatment (EW or TW), time by breed (Parda de Montaña orPirenaica), and time by weaning and breed interactions as fixedeffects, and individual as the random effect. A first-orderautoregressive structure with heterogeneous variances for eachdate was used to model heterogeneous residual error. To test fordifferences in least square means (LS Means), t-tests wereused. When a fixed effect was not significant, it was removedfrom the model.

Energy-corrected milk intake, carcass and meat qualitydata, and economic results were subjected to Analysis ofVariance using the GLM procedure of SAS, with weaningtreatment, breed, and their interaction as main effects. Whena main effect was not significant, it was removed from themodel. Pearson's correlation coefficients between variableswere calculated. Tests that had P-valuesb0.05 were consideredstatistically significant; those that had values b0.10 suggestedtrends.

3. Results and discussion

The interaction between age at weaning and breed wasnot significant for any of the evaluated data, unlikeMyers

Table 2Calf performance from birth to 150 d in early weaned and traditionally wea

Weaning1 Bree

Early weaned Traditionally weaned Pard

n 7 7 7

Weight (kg)At birth 44 44 46At 90 d 121 124 133At 150 d 192a 170b 192

ADG (kg/d)0 to 90 d 0.86 0.89 0.9590 to 150 d 1.26a 0.73b 1.05

1Early weaned at 90 d, traditionally weaned at 150 d.2W = age at weaning, B = breed.a, b Means within a row and main effect lacking a common superscript letterThe interaction between age at weaning and breed was not significant for an

et al. (1999a) described; therefore, the main effects (age atweaning and breed) were examined separately.

3.1. Effect of age at weaning

3.1.1. Calf performanceWeight at birth, ADG from birth to 90 d and, con-

sequently, weight at 90 d did not differ between bothtreatments (Table 2). Average ECM intake at 90 d wassimilar for early and traditionally weaned calves (8.0 vs.7.5 kg/d, respectively; SEM=1.90, P=0.66), and waspositively correlated (r=0.62, P=0.001) with ADGbetween 0 and 90 d.

Between 90 and 150 d, the ADG of early weanedcalves was 42% greater than that of traditionally weanedcalves and, consequently, they were 22 kg heavier at150 d (Table 2). The improvement of weight gains dueto early weaning when calves receive high-concentratediets has been reported previously (Myers et al., 1999a;Barker-Neef et al., 2001). In the current study, earlyweaned calves had an average concentrate intake in thisperiod of 3.41 kg/d and an outstanding G:F (0.37 kg ofgain/kg of DMI), while traditionally weaned calves hadan average ECM intake of 6.7 kg/d at 150 d, which wasinsufficient for the full expression of their growth po-tential. Others have documented the relatively greaterefficiency of early weaned calves during the early grow-ing phase (Fluharty et al., 2000).

During the finishing phase (from 150 d to slaughter),the ADG of calves in the two weaning treatments wassimilar (Table 3). The absence of a difference in weightgain during the finishing phase between early and tra-ditionally weaned animals has been observed in somestudies involving steers (Myers et al., 1999b; Fluharty

ned autumn-born Parda de Montaña and Pirenaica bull calves

d P-value2

a de Montaña Pirenaica SEM W B

7

42 1.9 0.99 0.57a 113b 4.7 0.72 0.01a 171b 7.6 0.006 0.01

0.80 0.082 0.72 0.080.94 0.094 0.001 0.17

differ (Pb0.05).y of the evaluated data.

Table 3Calf performance from 150 d to slaughter in early weaned and traditionally weaned autumn-born Parda de Montaña and Pirenaica bull calves

Weaning a Breed P-value b

Early weaned Traditionally weaned Parda de Montaña Pirenaica SEM W B

ADG, kg/d 1.63 1.68 1.65 1.66 0.035 0.50 0.84Slaughter weight, kg 449 449 447 451 4.6 0.94 0.55Age at slaughter, d 307 324 309 322 20.2 0.41 0.10Daily DMI, kg/d 5.83 5.74 5.92 5.65 0.444 0.71 0.23Total DMI, kg 908 970 923 956 84.2 0.15 0.43G:F, kg gain/kg DMI 0.28 0.29 0.28 0.30 0.018 0.21 0.11

The interaction between age at weaning and breed was not significant for any of the evaluated data.a Early weaned at 90 d, traditionally weaned at 150 d.b W = age at weaning, B = breed.

107M. Blanco et al. / Livestock Science 120 (2009) 103–115

et al., 2000; Schoonmaker et al., 2004), but not in astudy of spring-born bull calves under our conditions(Blanco et al., 2008). The duration and severity of feedrestrictions greatly influence compensatory growth(Ryan, 1990) and, in the current study, the restrictedgrowing phase of traditionally weaned calves mighthave been too short (60 d) to induce compensatorygrowth when they were given concentrates ad libitum.Besides, a restriction around weaning, when the

Fig. 1. Effect of age at weaning (left, EW: Early weaning; TW: Traditional weagains and daily DMI over 30-day periods during the finishing phase (150 d toat Pb0.01 and ⁎ at Pb0.05. The interaction between age at weaning and br

development of muscle and bone tissues is preponder-ant, could compromise subsequent growth (Hoch et al.,2005). Weight gains of the two treatments differedbetween 150 and 180 d (Fig. 1), when traditionallyweaned calves, which were still acclimatizing to feed-lot conditions, had lesser weight gains than did earlyweaned calves. It was also different between 210 and240 d, when traditionally weaned calves had a greaterADG than early weaned calves. At slaughter at 450 kg,

ning) and breed (right, PM: Parda de Montaña; PI: Pirenaica) on weightslaughter). Means within a period with ⁎⁎⁎ differ at Pb0.001, ⁎⁎ differeed was not significant for any of the evaluated data.

108 M. Blanco et al. / Livestock Science 120 (2009) 103–115

traditionally weaned calves were only 17 d older thanwere early weaned calves (P=0.41).

During the finishing phase, the overall daily DMI ofearly and traditionally weaned calves did not differand, consequently, the total DMI and G:F of the twotreatments were similar, as Fluharty et al. (2000) ob-served in early and traditionally weaned steers slaugh-tered at a target weight. When daily DMI across 30-dayperiods was studied, differences appeared in the firstmonth, when early weaned calves, which had alreadyadapted to the intensive diet, had a greater daily DMIthan did traditionally weaned calves (Fig. 1), and thethird month when traditionally weaned calves hadgreater daily DMI than early weaned calves. Other-wise, the two treatments did not differ in feed intakethroughout the finishing phase. Over the entire feed-lot phase (from weaning at either age to slaughter),early weaned calves stayed longer in the feedlot thantraditionally weaned calves (217 vs. 174 d, respectively;SEM=20.1, P=0.001) and had a greater total DMI(1128 kg vs. 970 kg, respectively; SEM=92.3,P=0.002).Myers et al. (1999b) reported similar findings.

3.1.2. Serum IGF-I and leptin concentrationsAge at weaning affected the time course of serum

IGF-1 concentrations (Fig. 2). At 90 d, early andtraditionally weaned calves had similar IGF-I concentra-

Fig. 2. Effect of age at weaning and breed on serum IGF-I and leptin concentrweaning and breed was not significant for any of the evaluated data. MeaSEDleptin=0.3.

tions, but at 150 d, IGF-I concentrations of early weanedcalves were 2.5 times greater than those of traditionallyweaned calves (P=0.001). Serum IGF-I concentration oftraditionally weaned calves did not increase probablybecause under conditions of feed restriction, the age-related increase in the IGF-I concentrations of calves canbe attenuated (Elsasser et al., 1989; Hayden et al., 1993).From 150 d to slaughter, IGF-I concentrations increasedin both groups of calves (P=0.001) and, at slaughterthe two treatments had similar values. In that period,the relative increase was greater in traditionally weanedcalves (P=0.001). The different patterns can be at-tributed to differences in the energy content of the diets.

Serum leptin concentrations were only affected bysampling date. Early and traditionally weaned calveshad similar leptin concentrations at 90 d, 150 d, and atslaughter (Fig. 2). In both treatments, leptin concentra-tions increased by N40% during fattening (P=0.001).An increase in leptin concentrations during fatteningoccurs in bulls (Bellmann et al., 2004) and steers(Hersom et al., 2004).

IGF-I concentrations at 90 d were positively cor-related with ADG from birth to 90 d (r=0.54) (P=0.004).Elsasser et al. (1989) and Hayden et al. (1993) alsoreported positive correlations between IGF-I and ADG incalves. Moreover, IGF-I at 150 d and ADG between 90and 150 d were positively correlated (r=0.77, P=0.001).

ations1 throughout the production cycle. The interaction between age atns with ⁎⁎⁎ at a measuring date differ at Pb0.001. 1SEDIGF-I=33.7,

109M. Blanco et al. / Livestock Science 120 (2009) 103–115

On the other hand, early weaned calves had high ADGand IGF-I concentrations, but low leptin concentrations,at 150 d. High IGF-I concentrations have been associatedwith high protein deposition (Hayden et al., 1993), whichis relatively more important in the early feedlot phase(Owens et al., 1995). Thus, lean growth might havemainly occurred during this period, which is consistentwith the high feed efficiency observed. Serum IGF-Iconcentrations at 150 d of early weaned calves wascorrelated with the daily DMI from 90 to 150 d (r=0.66,P=0.02), G:F from 90 to 150 d (r= 0.71, P=0.02), andG:F in the finishing phase (r=−0.74, P=0.02). Thus,IGF-1 at 150 d could be used as an indicator of feedefficiency during the finishing phase, as was recom-mended for beef cattle (Moore et al., 2005). In both earlyand traditionally weaned calves, ADG, IGF-I, and leptinconcentrations increased from 150 d until slaughter, butno significant relationship was detected among thesevariables. Although IGF-I concentrations were indicativeof growth potential at some points in the productioncycle, it was not a suitable predictor for ADG in the longterm (see also Kerr et al., 1991; Connor et al., 2000).

In early and traditionally weaned calves, leptinconcentrations were not correlated with carcass fatnessor conformation scores. However, leptin concentrationhad been proposed as a predictor of carcass compositionand quality grade by Geary et al. (2003), who foundsignificant correlations between these traits, which wasnot the case in the current study.

Leptin concentrations at slaughter were positivelycorrelated with fat content of the Longissimus dorsi(Table 6) in traditionally weaned calves (r=0.73,P=0.003), but not in early weaned calves (r=0.33,P=0.29). Only when leptin concentrations were above4.6 ng/ml was there a positive correlation with intramus-cular fat content. Leptin concentrations at slaughter were

Table 4Carcass characteristics in early weaned and traditionally weaned autumn-bo

Weaning1

Early weaned Traditionally weaned

Carcass weight, kg 258 255Dressing percentage 57.70 56.90Conformation (1 to 18) 11.2a 10.2b

Fatness score (1 to 15) 5.4 5.0Fat colour

Luminosity (L⁎) 75.3 75.5Hue angle value 83.1 79.6

1Early weaned at 90 d, traditionally weaned at 150 d.2W = age at weaning, B = breed.a, b Means within a row and main effect lacking a common superscript letterThe interaction between age at weaning and breed was not significant for an

low because the Parda de Montaña and Pirenaica breedsare relatively lean (see below) and calves were slaugh-tered at a young age, which is typical of beef productionsystems in the Mediterranean region. In Wagyu andHolstein steers, circulating leptin concentrations and intra-muscular fat content were positively correlated (Wegneret al., 2001). It is possible that during the finishing phaseearly weaned calves started to deposit fat earlier than didtraditionally weaned calves because, from d 90 to 150,early weaned calves had already been intensively fed,while traditionally weaned calves were restricted becausethey were still nursing their dams. Leptin has a feedbackregulation to avoid excessive fattening (Chilliard et al.,1999), which could be acting on early weaned calves inthe last part of the finishing phase while traditionallyweaned calves were still depositing fat. Thus, the positivecorrelation between intramuscular fat content and leptinconcentrations at slaughter in early weaned, but not intraditionally weaned calves, might be influenced by thestage of fat deposition.

3.1.3. Carcass and meat qualityAge at weaning did not influence carcass weight or

dressing percentage (Table 4), which agrees with theresults reported in steers slaughtered at a target weight(Fluharty et al., 2000) or backfat thickness (Myers et al.,1999b; Schoonmaker et al., 2004).

In the current study, early weaned calves showedbetter carcass conformation than traditionally weanedcalves (P=0.04) but similar fatness score and fat colour.Myers et al. (1999a) reported an improvement in thecarcass quality of early weaned steers slaughtered at asimilar weight to the one used in the current study. Whensteers (Schoonmaker et al., 2004) and bulls (Blancoet al., 2008) were slaughtered at heavier weights, age atweaning had no significant effect on conformation or

rn Parda de Montaña and Pirenaica bull calves

Breed P-value2

Parda de Montaña Pirenaica SEM W B

252b 262a 9.8 0.54 0.0456.39b 58.26a 1.435 0.27 0.0210.2b 11.2a 0.87 0.04 0.045.4 5.0 0.53 0.15 0.23

76.5a 74.3b 1.68 0.84 0.0282.9 79.8 4.38 0.11 0.17

differ (Pb0.05).y of the evaluated data.

Table 5Meat pH, instrumental colour, and texture of Longissimus dorsimuscle in early weaned and traditionally weaned autumn-born Parda de Montaña andPirenaica bull calves

Weaning1 Breed P-value2

Early weaned Traditionally weaned Parda de Montaña Pirenaica SEM W B

pH 5.61 5.56 5.59 5.58 0.081 0.29 0.85Instrumental colourLuminosity (L⁎) 43.2 45.1 43.3 45.0 2.53 0.14 0.20Hue angle value 46.6 46.6 45.4b 47.8a 2.17 0.99 0.04

Toughness3, kg/cm2 1.81 1.78 1.91 1.68 0.335 0.83 0.18Maximum stress3, kg/cm2 5.77 5.84 6.29 5.31 1.089 0.89 0.081Early weaned at 90 d, traditionally weaned at 150 d.2W = age at weaning, B = breed.3After 7 d of ageing.a, b Means within a row and main effect lacking a common superscript letter differ (Pb0.05).The interaction between age at weaning and breed was not significant for any of the evaluated data.

110 M. Blanco et al. / Livestock Science 120 (2009) 103–115

fatness scores, probably because the effect is weakenedby a longer feedlot period.

Meat pH did not differ between the two weaningtreatments (Table 5) because both groups were subjectedto the same pre-slaughter management practices andprocedures to minimize stress at slaughter. The meatfrom early and traditionally weaned calves had similarluminosity and Hue angle values. Barker-Neef et al.(2001) reported greater luminosity in traditionallyweaned calves than in early weaned calves. Moreover,early weaned and traditionally weaned calves did notdiffer in meat tenderness and maximum stress, as othersreported (Barker-Neef et al., 2001; Schoonmaker et al.,2004).

Age at weaning had little effect on meat chemicalcomposition (Table 6). Although early weaned calves hada greater dry matter content than traditionally weaned

Table 6Longissimus dorsi chemical composition and lipid composition† in early wPirenaica bull calves

Weaning1 Br

Early weaned Traditionally weaned Pa

Dry matter 25.0a 24.1b 24Crude protein 20.9a 20.3b 20Intramuscular fat 1.9 1.7 1SFA, % 43.6 43.9 43MUFA, % 33.4 35.9 35PUFA, % 12.7 11.2 11PUFA/SFA ratio 0.29 0.26 0

† SFA: Saturated Fatty Acids; MUFA: Monounsaturated Fatty Acids; PUFA1Early weaned at 90 d, traditionally weaned at 150 d.2W = age at weaning, B = breed.a, b Means within a row and main effect lacking a common superscript letterThe interaction between age at weaning and breed was not significant for an

calves and, concomitantly, a greater protein content ex-pressed on wet basis, the differences were small. Whenprotein content was expressed on a dry-weight basis, thetwo weaning treatments did not differ (data not shown).Intramuscular fat content was similar in early andtraditionally weaned calves. Accordingly, meat chemicalcomposition did not differ between early and normalweaned steers slaughtered at a constant weight (Schoon-maker et al., 2001). However, when normal weaned steerswere heavier at slaughter than their early weaned counter-parts, the former tended to present greater intramuscularfat (Barker-Neef et al., 2001) and greater dry mattercontent (Schoonmaker et al., 2004).

Early weaned and traditionally weaned calves hadsimilar meat fatty acid profiles, except for C18:1, whichwas lesser in early than traditionally weaned calves(29.7% vs. 31.6%, respectively; SEM=1.85, P=0.05).

eaned and traditionally weaned autumn-born Parda de Montaña and

eed P-value2

rda de Montaña Pirenaica SEM W B

.4 24.6 0.55 0.002 0.56

.6 20.6 0.42 0.004 0.88

.9 1.7 0.45 0.37 0.39

.3 44.2 1.46 0.63 0.47

.3 34.0 2.31 0.07 0.16

.5 12.4 2.40 0.19 0.46

.27 0.28 0.063 0.25 0.54

: Polyunsaturated Fatty Acids.

differ (Pb0.05).y of the evaluated data.

111M. Blanco et al. / Livestock Science 120 (2009) 103–115

Consequently, total MUFA were slightly lesser in earlyweaned calves than in traditionally weaned calves(Table 6); however, the SFA, PUFA, and PUFA/SFAratio of the twoweaning treatments were similar, as theseparameters are mainly related to the diet fed to calves(Serrano et al., 2007).

3.1.4. Economic performanceThe value of calves at weaning varied with age at

weaning, as it was lesser for early than for traditionallyweaned calves (Table 7) because the former were lighterat weaning. Early weaned calves had greater total DMIthan traditionally weaned calves, and their feed costs werealmost 20% greater than those of traditionally weanedcalves (Table 7). Moreover, because early weaned calvesstayed longer in the feedlot, their yardage costs weregreater. Thus, the greater cost for the purchase oftraditionally weaned calves was compensated for bylesser feed and yardage expenses. Consequently, thetotal costs of early and traditionally weaned calves weresimilar. Barker-Neef et al. (2001) reported similar results.Conversely, Story et al. (2000) reported that traditionallyweaned steers had lesser total costs than early weanedsteers.

Income received for early weaned calves was slightlygreater than that of traditionally weaned calves becausethe value of their carcasses was greater because oftheir better conformation. When early and traditionallyweaned steers had similar carcass qualities, income per-ceived was similar (Story et al., 2000). Others reporteddifferences associated with the lighter carcasses of earlyweaned calves (Barker-Neef et al., 2001).

Early weaned calves had a lesser value at weaningand greater total costs, but provided a slightly greaterincome, which compensated for the extra cost associatedwith the longer intensive phase, and therefore, like Storyet al. (2000), no differences in the economic marginsrelated to weaning strategy were found.

Table 7Economic performance (Euros) in early weaned and traditionally weaned au

Weaning1

Early weaned Traditionally weaned

Calf value at weaning 518b 553a

Feed cost 262a 224b

Facility rental cost 46a 37b

Income 828 802Economic margin 2 −121Early weaned at 90 d, traditionally weaned at 150 d.2W = age at weaning, B = breed.a, b Means within a row and main effect lacking a common superscript letterThe interaction between age at weaning and breed was not significant for an

3.2. Effect of breed

3.2.1. Calf performanceParda de Montaña calves tended (P=0.08) to have a

greater overall ADG from birth to 90 d than Pirenaicacalves (Table 2). Similarly, Sanz et al. (2003) reportedgreater weight gains in Parda de Montaña than inPirenaica calves during this period. In fact, in the currentstudy, weight gains of Parda de Montaña and Pirenaicabreeds were only similar during their first month of life,whereas ADG was 15% greater in month 2 (P=0.09)and 28% greater in month 3 (P=0.02) in Parda deMontaña calves. Because of those differences, Parda deMontaña calves were heavier at 90 d than Pirenaicacalves (see also Sanz et al., 2003). At 90 d, Parda deMontaña and Pirenaica calves had similar ECM intakes(8.2 kg/d and 7.3 kg/d, respectively; SEM=1.90,P=0.35), although other studies found differences inECM yields between the breeds (e.g., Casasús et al.,2004).

From 90 to 150 d, regardless of age at weaning, breeddid not affect performance (Table 2). Weight gains ofParda deMontaña and Pirenaica calves were similar bothnursing (traditionally weaned) and at the feedlot (earlyweaned). Therefore, the differences in weight at 90 dwere maintained at 150 d, when Parda deMontaña calveswere 20 kg heavier (P=0.01), which has been observedby Villalba et al. (2000). The ECM intakes of nursingcalves at 150 d were similar in Parda de Montaña andPirenaica calves (6.7 vs. 6.6 kg/d, respectively;SEM=1.78, P=0.93). In the same period, the concen-trate intakes of early weaned calves at the feedlot weresimilar in Parda deMontaña and Pirenaica calves (3.5 vs.3.3 kg/d, respectively; SEM=0.70, P=0.72).

During the finishing phase (150 d to slaughter), theADG between 150 d and 180 d was greater in Parda deMontaña calves than in Pirenaica calves (Fig. 1). On thecontrary, Parda de Montaña calves had lesser ADG than

tumn-born Parda de Montaña and Pirenaica bull calves

Breed P-value2

Parda de Montaña Pirenaica SEM W B

542 529 14.3 0.001 0.09240 246 21.4 0.001 0.5440 42 4.2 0.001 0.19789b 841a 35.2 0.15 0.007−23b 33a 37.9 0.49 0.01

differ (Pb0.05).y of the evaluated data.

112 M. Blanco et al. / Livestock Science 120 (2009) 103–115

Pirenaica calves between 270 and 300 d, and between300 and 330 d. The great weight gains of Pirenaicacalves at the end of the finishing period support theirclassification as a late-maturing breed (Piedrafita et al.,2003), while weight gains of Parda de Montaña calvesmust have reached a plateau earlier. Parda de Montañacalves and Pirenaica calves gained weight faster at thebeginning and the end of the finishing phase, respec-tively (Fig. 1). Consequently, overall ADG was similarin both breeds (Table 3). Those results are similar tothose reported for calves of these breeds weaned at 5 to6 months and subsequently fed intensive diets (Albertíet al., 1997; Campo et al., 1999; Piedrafita et al., 2003).Thus, the ages at which the target slaughter weight of450 kg was attained were similar in Parda de Montañaand Pirenaica calves (309 vs. 322 d, respectively;SEM=20.2, P=0.10).

Overall daily DMI and feed efficiency from 150 d toslaughter were similar in the two breeds (Table 3), asAlbertí et al. (1997) reported previously. Daily DMI ofParda de Montaña and Pirenaica calves differed onlyduring the first and the last month of the finishing phase(Fig. 1). In the last month, daily DMI was greater inPirenaica calves than in Parda de Montaña calves(Fig. 1), which might explain the greater weight gains byPirenaica calves at the end of the finishing phase. Overthe entire feedlot phase (from weaning at either age toslaughter), total DMI did not differ between Parda deMontaña calves and Pirenaica calves (1032 vs. 1066 kg,respectively; SEM=92.3, P=0.46) nor did the num-ber of days on feed (189 d and 202 d, respectively;SEM=20.1, P=0.20).

3.2.2. Serum IGF-I and leptin concentrationsSerum IGF-I and leptin concentrations varied with

sampling date, but they did not differ between breedsand there was no significant interaction between breedand sampling date. Breed had no effect on IGF-I con-centrations, partly because IGF-I showed high indivi-dual variability (see also Elsasser et al., 1989). The IGF-I concentrations of the two breeds did not differ at 90 d,150 d, or at slaughter (Fig. 2). Similarly, the leptinconcentrations of the breeds were similar at 90 d, 150 d,and at slaughter. Under similar feeding conditions,Parda de Montaña and Pirenaica calves might havesimilar adipocyte size (Mendizabal et al., 1999), and thesize of adipose cells determines the concentrations ofcirculating leptin (Chilliard et al., 1999).

Leptin concentrations at slaughter were negativelycorrelated with the slaughter weight (r=0.74, P=0.006)in Pirenaica calves and with fatness score in Parda deMontaña calves (r=0.58, P=0.03). On the other hand,

Pirenaica calves, but not Parda de Montaña calves,showed a strong correlation between leptin at slaughterand meat intramuscular fat content (r=0.85; P=0.001).Bellmann et al. (2004) reported a positive correlationbetween leptin concentrations and body fat in Charolais,but not inHolstein, bull calves. In our study, intramuscularfat content in Parda deMontaña calveswas comparativelylow for the breed standards (see below), whichmight havebeen responsible for the absence of correlations. Inanother study, Parda de Montaña calves slaughtered atheavier weights than in this study had greater intramus-cular fat content, which was positively correlated withleptin concentrations at slaughter (Blanco, unpublisheddata).

3.2.3. Carcass and meat qualityDespite similar slaughter weights, Pirenaica calves

had better-conformed (P=0.04) and heavier carcasses(P=0.04), and concomitant greater dressing percentages(P=0.02) than Parda de Montaña calves (Table 4). Thetwo breeds had similar fatness score (see also Campo etal., 1999). When Pirenaica and Parda de Montaña calveswere slaughtered at heavier weights, however, dressingpercentage and conformation did not differ, although thecarcasses of Pirenaica calves were leaner than those ofParda de Montaña calves (Piedrafita et al., 2003). Breedinfluenced subcutaneous fat colour (Table 4). The twobreeds had similar Hue angle values, but Parda deMontaña calves had greater luminosity than Pirenaicacalves. Sañudo et al. (1998) found differences in bothtraits.

As expected, the meat pH of the two breeds did notdiffer (Table 5), were within the range expected foranimals that have not been stressed before slaughter, andwere similar to those reported by Sañudo et al. (1998).The breeds did not differ in meat luminosity (Table 5),but Hue angles were greater in Pirenaica calves than inParda de Montaña calves (P=0.04), which was ob-served by Sañudo et al. (1998) in calves at a similarslaughter weight. Gil et al. (2001) reported thatPirenaica calves had greater Hue angle values thanBruna dels Pirineus (analogous to Parda de Montaña)calves as a result of their greater glycolytic capacity. Inthe current study and in those of Sañudo et al. (1998)and Campo et al. (1999), meat toughness was similar inboth breeds (Table 5), but Pirenaica calves tended tohave maximum stress values that were lesser than thoseof Parda de Montaña calves (P=0.08). When calves ofboth breeds were slaughtered at 330 kg, toughness andmaximum stress were greater in Parda de Montañacalves than in Pirenaica calves, but the differencesdisappeared at a 550-kg slaughter weight (Sañudo et al.,

113M. Blanco et al. / Livestock Science 120 (2009) 103–115

2004). Therefore, at the intermediate slaughter weightused in our study (450 kg), it is understandable thatPirenaica calves tended to have lesser values for max-imum stress.

Breed did not influence meat chemical compositionon a wet-weight basis (Table 6). Parda de Montaña andPirenaica calves had similar values of DM, proteincontent and intramuscular fat content. The latter find-ing differs from studies in which Pirenaica calves wereleaner than were Parda de Montaña calves (Campo et al.,1999; Piedrafita et al., 2003), which was attributed to thediffering maturation rates of the two breeds. In thosestudies, however, Parda de Montaña calves had greatercarcass fatness scores and meat fat content than theParda de Montaña calves examined in the current study.

The two breeds had similar fatty acid composition.Indeed, only C16:0 (24.3% and 22.3% in Parda deMontaña and Pirenaica calves, respectively; SEM=1.18,P=0.004) and C14:0 (2.4% and 2.8%, respectively;SEM=0.41, P=0.05) were different between the breeds,which had similar SFA, MUFA, PUFA, and PUFA/SFAratio (Table 6). Insausti et al. (2004) reported differencesbetween the two breeds in most of the fatty acids andintramuscular fat content, but not in the SFA, MUFA,PUFA, and PUFA/SFA ratio.

3.2.4. Economic performanceParda de Montaña calves were heavier than Pirenaica

calves at weaning, which led to a slightly greater valuefor Parda deMontaña calves at weaning (P=0.09). Pardade Montaña and Pirenaica calves had similar concentrateintakes throughout the cycle; thus, feed costs for the twobreeds were similar (Table 7). On the other hand,Pirenaica calves stayed in the feedlot facility only13 days longer than Parda de Montaña calves; conse-quently, yardage expenses were not different between thetwo breeds. Pirenaica calves had heavier and better-conformed carcasses; therefore, income received was7% greater for their carcasses than for the carcasses ofParda de Montaña calves (P=0.007). Consequently, theeconomic margin was greater for Pirenaica calves, whichmakes this breed more interesting economically to feed-lot producers or suckler cattle farms that retain owner-ship of calves throughout the feedlot phase (Casasúset al., 2006).

4. Conclusion

The interaction between age at weaning and breedwas not significant in any of the parameters studied. Ageat weaning influenced growth patterns, but overallproduction and economic performance were similar in

the two weaning treatments, and differences in carcassand meat quality were only minor. The two breeds hadsimilar growth patterns, which differed slightly at cer-tain times. Feed costs were similar for Parda de Montañaand Pirenaica calves, but the carcasses of Pirenaicacalves yielded greater income, which led to a bettereconomic performance by Pirenaica calves comparedto Parda de Montaña calves. Thus, based on calfproductive and economic performance, regardless of thebreed, both weaning strategies are suitable for autumn-calving farms when calves are fattened within the sys-tem, whereas the use of the Pirenaica breed is moreprofitable under the conditions described in this study.Economic results should be regarded cautiously,because they were obtained in only one year and witha limited number of animals, while the price of thesystem inputs and outputs may vary in time. However,the technical results reported in this study provide thebasis for further economic evaluations in the event ofchanging economic conditions.

Acknowledgements

We wish to thank the farm staff working at LaGarcipollera Research Centre and CITA Research Centre,Mercazaragoza and BIMARCA S.A., for technicalsupport, and Departament de Producció Animal, Uni-versitat de Lleida, for meat fatty acid analyses. Researchfunded by project AGL 2002-00027 (MCyT). M. Blancoin receipt of a grant from INIA.

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