INTRODUCTION
A common European practice in dairy production is to inseminate dairy cows with semen derived from beef cattle if the calves are not to be used as replacement animals on the dairy farm (Dal Zotto et al. Reference Dal Zotto, Penasa, De Marchi, Cassandro, Lopez-Villalobos and Bittante2009; Keane & Moloney Reference Keane and Moloney2010). For example in Ireland, dairy cows not required for the production of replacement heifers are crossed with beef bulls (Keane & Moloney Reference Keane and Moloney2010), and according to Dal Zotto et al. (Reference Dal Zotto, Penasa, De Marchi, Cassandro, Lopez-Villalobos and Bittante2009), beef breed semen is used in 0·25–0·30 of the dairy cow inseminations in the Alps. In some cases, the use of beef breed semen has decreased in the more specialized herds because of fertility and longevity problems (Boettcher Reference Boettcher2005; Dal Zotto et al. Reference Dal Zotto, De Marchi, Dalvit, Cassandro, Gallo, Carnier and Bittante2007), but in the future it could increase due to the use of sexed semen (Hohenboken Reference Hohenboken1999; Cerchiaro et al. Reference Cerchiaro, Cassandro, Dal Zotto, Carnier and Gallo2007). In Finland, Nordic Red (NR) is the most frequently used dairy breed but beef breed semen is used only in 0·06 of the dairy cow inseminations, indicating a clear possibility of increasing the use of beef breed semen.
Crossbreeding between dairy and beef cattle breeds has been investigated by several authors in the past (Andersen et al. Reference Andersen, Liboriussen, Thysen, Kousgaard and Buchter1976; Nelson et al. Reference Nelson, Beavers and Stewart1982) and also more recently (McGee et al. Reference McGee, Keane, Neilan, Moloney and Caffrey2005; Huuskonen et al. Reference Huuskonen, Pesonen, Kämäräinen and Kauppinen2013). Wolfová et al. (Reference Wolfová, Wolf, Kvapilik and Kica2007) have established a superior financial value from the meat of dairy and beef crossbreeds when compared with pure dairy cattle. Generally, proportions of hind quarter and/or proportions of hind quarter lean or muscle tissue are higher for beef crosses than for purebred dairy breeds, so crossbreds have produced more valuable carcasses (Keane et al. Reference Keane, More O'Ferrall and Connolly1989; Keane Reference Keane1994). Moreover, the ‘eating characteristics’ of meat from crossbreds is better (Davies et al. Reference Davies, Grundy and Page1992), and carcass yields are greater (Güngör et al. Reference Güngör, Alçiçek and Önenç2003) than purebreds. However, when the growth and carcass characteristics of different breed groups are compared, it is found that the amount of experimental crossbreed animals is often limited. Consequently, there is a concern about the representativeness of the experimental animals compared with other animals from the same breed groups, i.e. whether they cover the whole variation in their respective populations.
The main objective of the present research, based on a large dataset collected from Finnish slaughterhouses, was to study the potential for improvement of growth and carcass characteristics through NR×beef breed crossbreeding compared with purebred NR bulls. The second objective was to evaluate carcass traits (conformation, fat score) in relation to carcass weight in different breed groups. The third objective was to examine possible differences in feed intake and feed efficiency parameters in crossbred bulls compared with pure NR bulls. It was hypothesized that the use of beef breed crossbreeding improves carcass production compared with purebred NR bulls and production traits improve more by using late-maturing (Continental) beef breeds compared with early-maturing (British) breeds.
MATERIALS AND METHODS
Dataset – complete slaughter data
The dataset used for studying carcass characteristics was collected from four Finnish slaughterhouses (A-Tuottajat Ltd., P.O. Box 908, FI-60061 Atria, Finland; HK-Agri Ltd., P.O. Box 50, FI-20521 Turku, Finland; Saarioinen Lihanjalostus Ltd., P.O. Box 108, FI-33101 Tampere, Finland, and Snellman Lihanjalostus Ltd., Kuusisaarentie 1, FI-68600 Pietarsaari, Finland). These slaughterhouses are major meat companies in Finland, which, as a part of their business operations, transfer calves from dairy farms or suckler cowherds to cooperating farms for fattening, and subsequently slaughter the animals.
The raw slaughter data for each animal included individual animal identification number on ear tag, date of birth, date of slaughter, sex, carcass weight, carcass conformation score (EUROP) and carcass fat score (EUROP). Identities of breeds (dam and sire breed) were collected from the National Animal Identification Register for Cattle (ProAgria Agricultural Data Processing Centre, P.O. Box 25, FI-01301 Vantaa, Finland). Slaughtering data and identities of breeds for individual animals were linked through individual animal identification numbers. All purebred NR and NR×beef-breed crossbred bulls aged 365–730 days old and slaughtered by the above-mentioned slaughterhouses during 2009–2011 were selected for the study.
In all slaughterhouses, the carcasses were weighed hot after slaughter and the cold carcass weight was estimated as 0·98 of the hot carcass weight. The carcasses were classified for conformation and fatness using the EUROP quality classification (EC 2006). For conformation, development of carcass profiles, in particular the essential parts (round, back, shoulder), was taken into consideration according to the EUROP classification (E: excellent, U: very good, R: good, O: fair, P: poor), and for fat cover, the amount of fat on the outside of the carcass and in the thoracic cavity was taken into account using a classification range from 1 to 5 (1: low, 2: slight, 3: average, 4: high, 5: very high). Each level of the conformation scale was subdivided into three sub-classes (e.g. O+, O, O−) to produce a transformed scale ranging from 1 to 15, with 15 being the best conformation.
Birth weight assumptions used in the calculations were 40 kg live weight (LW) and 16 kg carcass weight for bull calves, since the same values were used by A-Tuottajat Ltd. in daily extension work (Herva et al. Reference Herva, Virtala, Huuskonen, Saatkamp and Peltoniemi2009, Reference Herva, Huuskonen, Virtala and Peltoniemi2011). An estimated daily carcass gain was calculated by subtracting 16 kg birth carcass weight from the reported slaughter weight and dividing the result by age at slaughter. The complete final slaughter data comprised 176 996 slaughtered bulls; the average slaughter age was 592 days and the mean carcass weight 332 kg (Table 1). The average estimated daily carcass gain was 537 g/d, the EUROP conformation score 4·9 and the carcass fat score 2·4.
Table 1. Description of the experimental data
* 0·05-quantile (∼5% of the data has a value less than the 0·05-quantile).
† 0·95-quantile (∼95% of the data has a value less than the 0·95-quantile).
‡ Conformation: (1=poorest, 15=excellent).
§ Fat cover: (1=leanest, 5=fattest).
Dataset – commercially dressed
In order to estimate valuable cuts for the studied breed groups, a separate dataset was collected during 2010/11 from Snellman Lihanjalostus Ltd. In addition to the variables mentioned above, this dataset also included information on commercial cuttings. After classification, the carcasses were chilled overnight below 7 °C and on the day after slaughter the carcasses were commercially dressed into valuable cuts (outside round (Musculus semitendinosus), inside round (Musculus semimembranosus), corner round (Musculus quadriceps femoris), roast beef (Musculus gluteus medius), tenderloin (Musculus psoas major) and loin (Musculus longissimus)) and tallow (subcutaneous fat) as described by Manninen et al. (Reference Manninen, Honkavaara, Jauhiainen, Nykänen and Heikkilä2011) and Pesonen et al. (Reference Pesonen, Honkavaara and Huuskonen2012). The amount of tallow was evaluated by cutting off the visible subcutaneous fat on the surface of prime cuts and by weighing the yield of tallow in grams. All these cuts were weighed during the dressing process with an automatic weighing system in the slaughter line and their yields were expressed as proportions of the carcass cold weight (0·98×carcass hot weight, 50 min post mortem).
This dataset comprised 16 827 slaughtered bulls (Table 1). The mean carcass weight was 4% lower than that in the complete slaughter data, but the average conformation and fat scores were almost the same in both datasets.
Feeding experiment
The feeding experiment was conducted in the experimental barn of the North Ostrobothnia Research Station of MTT Agrifood Research Finland (Ruukki, 64°44′N, 25°15′E) and started in January 2011. The experiment comprised 36 bulls: nine purebred NR, nine NR×Aberdeen Angus (NR×Ab), nine NR×Limousin (NR×Li) and nine NR×Blonde d'Aquitaine (NR×Ba). The bulls in all the three crossbred breed groups were from three different sires, while those in the NR group were from seven different sires. The bulls were managed according to the Finnish legislation regarding the use of animals in scientific experimentation. All animals were purchased from local farms, and at the beginning of the experiment the animals were 200 days old, on average. Before the experiment started, the animals were fed and managed similarly. One NR×Li bull was excluded from the study due to several occurrences of bloat.
The bulls were placed in an insulated barn in adjacent tie-stalls. The width of the stalls was 0·70–0·90 m for the first 4 months and 1·13 m until the end of the experiment. The bulls were tied with a collar around the neck, and a 0·50 m long chain was attached to a horizontal bar 0·40–0·55 m above the floor. The floor surface was solid concrete under the forelegs and metal grids under the hind legs. No bedding was used on the floor. The animals were fed three times a day (at 08·00, 12·00 and 18·00 h). Refused feed was collected and measured at 07·00 h daily. The bulls had free access to water from an open water bowl during the experiment.
The animals were offered total mixed ration (TMR) ad libitum (proportionate refusals as 0·05). The dry matter (DM) of the TMR consisted of grass silage (500 g/kg DM), rolled barley (425 g/kg DM) and rapeseed meal (75 g/kg DM). The daily ration for the bulls included also 150 g of a mineral mixture (A-Rehu Ltd., P.O. Box 908, FI-60061 Atria, Finland: KasvuApeKivennäinen: calcium 260, phosphorus 0, sodium 70, magnesium 35 g/kg). A vitamin mixture (Suomen Rehu Ltd., Xylitol ADE-Vita: vitamin A at 2 000 000 IU/kg, vitamin D3 at 400 000 IU/kg, vitamin E as DL-α-tocopherol acetate 1000 mg/kg and DL-α-tocopherol 900 mg/kg, selenium at 10 mg/kg) was given at 50 g per animal weekly.
Silage sub-samples (0·5 kg of fresh silage) for chemical analyses were taken twice a week, pooled over periods of 4 weeks and stored at −20 °C. Thawed samples were analysed for DM, ash, crude protein (CP), ether extract, neutral detergent fibre (NDF), starch, silage fermentation quality (pH, water-soluble carbohydrates (WSC), lactic and formic acids, volatile fatty acids, soluble and ammonia N content of N) and digestible organic matter in DM (D value). Concentrate subsamples were collected weekly, pooled over periods of 8 weeks and analysed for DM, ash, CP, ether extract, NDF and starch. The analyses of DM, ash, CP, ether extract, NDF and starch were made as described by Huuskonen (Reference Huuskonen2011) and Pesonen et al. (Reference Pesonen, Honkavaara, Kämäräinen, Tolonen, Jaakkola, Virtanen and Huuskonen2013). The silage was analysed for fermentation quality by electrometric titration as described by Moisio & Heikonen (Reference Moisio and Heikonen1989) and for D value by the method described by Nousiainen et al. (Reference Nousiainen, Ahvenjärvi, Rinne, Hellämäki and Huhtanen2004). The metabolizable energy (ME) value of the silage was calculated as 0·016×D value (MAFF 1984). The ME values of the concentrates were calculated based on concentrations of digestible crude fibre, CP, ether extract and nitrogen-free extract described by MAFF (1984). The digestibility coefficients of the concentrates were taken from the Finnish feed tables (MTT 2013). The values of amino acids absorbed from the small intestine (AAT) and the protein balance in the rumen (PBV) were calculated according to the Finnish feed tables (MTT 2013).
The grass silage used in the feeding trial was primary growth from a timothy (Phleum pratense) and meadow fescue (Festuca pratensis) sward and ensiled in bunker silos with a formic acid-based additive (AIV-2 Plus: 760 g formic acid/kg and 55 g ammonium formate/kg, supplied by Kemira Ltd., P.O. Box 171, FI-90101 Oulu, Finland) applied at a rate of 5 litres/tonne of fresh grass. The grass silage used was of good nutritional quality, as indicated by the D value as well as the AAT and CP contents (Table 2). The fermentation characteristic of the silage was also good, as indicated by the pH value and the low concentration of ammonia N and total acids. The silage was restricted and fermented with high residual WSC concentration and low lactic acid concentration. The concentrate feeds used had typical chemical composition and feed values (Table 2).
Table 2. Chemical composition and feeding values of grass silage, barley, rapeseed meal and total mixed ration (TMR) used in the feeding experiment
The animals were weighed on two consecutive days at the beginning of the experiment and thereafter approximately every 56 days. Before slaughter they were weighed on two consecutive days. The average slaughter age was 553 days. The live weight gain (LWG) was calculated as the difference between the means of initial and final live weights divided by the number of growing days. The estimated rate of carcass gain was calculated as the difference between the final carcass weight and the carcass weight at the beginning of the experiment divided by the number of growing days. Carcass weight at the beginning of the experiment was assumed to be 0·50×initial LW, which was used also in studies by Root & Huhtanen (Reference Root and Huhtanen1998) and Huuskonen et al. (Reference Huuskonen, Tuomisto, Joki-Tokola and Kauppinen2009) and which was assessed based on earlier studies (unpublished data).
The animals were slaughtered in the Atria slaughterhouse in Kuopio in two batches and all four breed groups were represented in both the batches. After slaughter the carcasses were weighed hot and the cold carcass weight was estimated as 0·98 of the hot carcass weight. Carcass yields were calculated from the ratio of cold carcass weight to final LW. The carcasses were classified for conformation and fatness using the EUROP quality classification (EC 2006) as described earlier.
Statistical methods
The results of the complete slaughter data and commercial cuttings are shown as least-squares means. The normality of residuals and the homogeneity of variances were checked using graphical methods: box-plots and scatter plots of residuals and fitted values. The data were subjected to the analysis of variance using the SAS Mixed procedure (version 9.2, SAS Institute Inc., Cary, NC). Differences between the breeds were compared using Dunnett's test so that purebred NR was used as a control breed.
The results of the feeding experiment are shown as least-squares means, because the records from one excluded animal were not replaced. The data were subjected to the analysis of variance using the SAS Mixed model procedure (version 9.2, SAS Institute Inc., Cary, NC). Animals were slaughtered in two batches and the model used included the random effect of the slaughter batch. The model was:
$$y_{ijk} = \mu + {\rm batch}_i + {\rm breed}_j + \varepsilon _{ijk} $$where μ is the intercept, batchi is the random effect of ith batch (i=1,2), breedj is the fixed effect of jth breed (j=NR, NR×Ab, NR×Li, NR×Ba) and ε ijk is the between-animal variation (=residual). Differences between the breed groups were compared using Dunnett's test so that the comparison of the breed groups was based on the purebred NR bulls.
RESULTS
Complete slaughter data and commercial cuttings
The complete slaughter data included 164 812 purebred NR bulls (Table 3). The most popular beef breed sires were Limousin (5293 observations), Aberdeen Angus (2329) and Blonde d'Aquitaine (1466), while Simmental (Si; 1270), Charolais (Ch; 1044) and Hereford (Hf; 782) were used less. The average slaughter age for purebred NR bulls was 592 days and there were no remarkable differences in the slaughter ages among breed groups. However, the NR×Ba (P<0·001), NR×Ch (P<0·05) and NR×Si (P<0·001) bulls were 9, 6 and 9 days younger than the NR bulls, respectively. In addition, the NR×Ab bulls were 4 days older than purebred NR bulls (P<0·05).
Table 3. Carcass gain, carcass characteristics and valuable cuts of purebred Nordic Red (NR) and NR×beef breed crossbred bulls in Finnish slaughter dataset. (Ab=Aberdeen Angus, Ba=Blonde d'Aquitaine, Ch=Charolais, Hf=Hereford, Li=Limousin, Si=Simmental)
* Differences between the breed groups were compared using Dunnett's test so that purebred NR was used as a control breed.
† s.e.m., standard error of the mean.
‡ Conformation: (1=poorest, 15=excellent).
§ Fat cover: (1=leanest, 5=fattest).
All crossbred groups differed significantly (P<0·001) from NR bulls in both carcass weight and carcass gain (Table 3). The estimated average daily carcass gain of the NR bulls was 532 g/d, and it improved by 8, 16, 18, 9, 14 and 18% with NR×Ab, NR×Ba, NR×Ch, NR×Hf, NR×Li and NR×Si crossbreds, respectively, compared with pure NR bulls. The EUROP conformation score of the NR bulls was 4·7, and improved most (51–57%) by using Ba, Li and Ch sires (P<0·001). Carcasses from NR×Ab, NR×Hf and NR×Si crossbreds showed 28, 23 and 36% better conformation compared with purebred NR bulls (P<0·001). The carcass fat score of the NR bulls (2·4) was 9% higher than that of the NR×Ba bulls (P<0·001). With NR×Ab, NR×Ch, NR×Hf, NR×Li and NR×Si crossbreds the carcass fat score was 29, 4, 33, 8 and 13% higher compared with purebred NR bulls, respectively (P<0·001).
Dataset from commercial cuttings included 16 037 purebred NR bulls but the amount of the crossbreds was clearly lower (45–287 bulls/breed group) (Table 3). The carcass weights were somewhat lower than those in the complete slaughter data. Breed group had clear effects on the yield of valuable cuts. The yields of loin, tenderloin, inside round, outside round, corner round and roast beef were higher with NR×Ba, NR×Ch and NR×Li bulls compared with purebred NR bulls (P<0·001) (Table 3). Additionally, the yields of loin, tenderloin, inside round, outside round and roast beef were higher with NR×Si bulls than with pure NR bulls (P<0·001). Furthermore, the yields of inside round (P<0·05) and corner round (P<0·001) were higher with purebred NR bulls compared with NR×Ab bulls. The yield of subcutaneous fat was significantly lower in the NR bulls than in the NR×Ab, NR×Hf and NR×Si bulls. On the other hand, the yield of subcutaneous fat was 25% higher with purebred NR bulls compared with NR×Ba bulls (P<0·001).
Average carcass weights in different EUROP fat score classes and the incidence of different fat scores in breed groups are presented in Table 4. The most common class for NR, NR×Ba and NR×Ch bulls was fat score 2, including 0·55, 0·69 and 0·47 of all observations within the breed group, respectively. For NR×Ab, NR×Hf, NR×Li and NR×Si bulls, the incidence of fat score 3 was greater than score 2, being 0·47, 0·49, 0·45 and 0·49, respectively. Considering fat score 4, 0·27–0·28 of NR×Ab and NR×Hf carcasses were placed in this category. For other breed groups, only 0·02–0·10 of carcasses were ranked in class 4. In addition, 0·04–0·05 of NR×Ab and NR×Hf carcasses, but <0·01 carcasses for other breed groups were placed under fat score 5. In general, the average carcass weight of the crossbred bulls in different fat score classes was higher than that of the purebred NR bulls (Table 4). For example, in fat score 3 the average carcass weights were 3, 14, 16, 2, 10 and 13% higher with NR×Ab, NR×Ba, NR×Ch, NR×Hf, NR×Li and NR×Si crossbreds, respectively, compared with purebred NR bulls.
Table 4. Average carcass weights of purebred Nordic Red (NR) and NR×beef breed crossbred bulls in different EUROP fat score classes (1=leanest, 5=fattest). (Ab=Aberdeen Angus, Ba=Blonde d'Aquitaine, Ch=Charolais, Hf=Hereford, Li=Limousin, Si=Simmental)
* Differences between the breed groups were compared using Dunnett's test so that purebred NR was used as a control breed.
† s.e.m., standard error of the mean.
For purebred NR bulls, the majority of carcasses (0·87) were given conformation scores 4 (O−) to 6 (O+), with the most common being O (0·42 of all observations) (Table 5). Considering NR×Ab, NR×Hf and NR×Si crossbreds, 0·80, 0·84 and 0·77 of carcasses were given scores of 5 (O) to 7 (R−). For NR×Ba, NR×Ch and NR×Li bulls, a notable (0·24–0·28) amount of carcasses were ranked as class 8 (R). In addition, 0·10–0·11 of NR×Ba, NR×Ch and NR×Li carcasses, but <0·03 carcasses for other breed groups, were given a conformation score of 9 (R+). Considering the most common conformation classes (4–7), the average carcass weights of NR×Ab, NR×Ba, NR×Ch and NR×Li bulls were lower compared with purebred NR bulls. For example, in conformation score 7 (R−), the average carcass weights were 4, 7, 3 and 7% lower with NR×Ab, NR×Ba, NR×Ch and NR×Li crossbreds, respectively, compared with pure NR bulls. In other words, the classifications of these breed groups were better than the NR bulls in the same carcass weight. Between NR, NR×Hf and NR×Si bulls there were only minor significant differences in the average carcass weights in the same conformation score classes (Table 5).
Table 5. Average carcass weights of purebred Nordic Red (NR) and NR×beef breed crossbred bulls in different EUROP conformation score classes (1=poorest, 15=excellent). (Ab=Aberdeen Angus, Ba=Blonde d'Aquitaine, Ch=Charolais, Hf=Hereford, Li=Limousin, Si=Simmental)
* Differences between the breed groups were compared using Dunnett's test so that purebred NR was used as a control breed.
† s.e.m., standard error of the mean.
Feeding experiment
The average DM, ME and nutrient intakes of the bulls are presented in Table 6. The average daily DM and ME intakes were 9·40 kg/d and 111·8 MJ/d during the experiment. There were no significant differences in DM, ME or nutrient intakes between breed groups. The mean final LW of the bulls was 695 kg and LWG was 1311 g/d. Breed groups had no significant effects on final LW or LWG. Instead, the carcass gain of the NR×Ba bulls was 13% higher than that of the pure NR bulls (P<0·05). In addition, the carcass gain of the NR×Li bulls tended to be 8% higher than that of the NR bulls (P<0·1). The feed (kg DM/kg carcass gain) and energy (MJ/kg carcass gain) conversion rates of the NR×Ba bulls tended to be better compared with purebred NR bulls. There were no differences in feed or energy conversion between NR, NR×Ab and NR×Li bulls (Table 6).
Table 6. Daily dry matter (DM) intake, feed conversion, growth performance and carcass characteristics of purebred Nordic Red (NR) and NR×beef breed crossbred bulls in feeding experiment. (Ab=Aberdeen Angus, Ba=Blonde d'Aquitaine, Li=Limousin)
* Differences between the breed groups were compared using Dunnett's test so that purebred NR was used as a control breed.
† s.e.m., standard error of the mean.
‡ Conformation: (1=poorest, 15=excellent).
§ Fat cover: (1=leanest, 5=fattest).
Carcass weights of the NR×Ab, NR×Li and NR×Ba bulls were 5, 6 and 9% higher compared with NR bulls, respectively. Carcass yields of the NR×Li and NR×Ba bulls were 5 and 7% higher compared with NR bulls, respectively, but there was no significant difference in carcass yield between NR and NR×Ab bulls (Table 6). Breed group had also clear effects on the carcass conformation and fat scores in the feeding trial. The conformation scores of the NR×Ab, NR×Li and NR×Ba bulls were 18, 39 and 42% better compared with NR bulls, respectively. There was no difference in the carcass fat score between NR and NR×Ba bulls. In the NR×Ab and NR×Li bulls, the fat scores were 39 and 13% higher compared with NR bulls, respectively.
DISCUSSION
Lifetime daily carcass gain (537 g/d, on average) observed in the present slaughter data was in line with the observations reported by Huuskonen et al. (Reference Huuskonen, Pesonen, Kämäräinen and Kauppinen2013) based on a corresponding dataset with purebred Holstein–Friesian (Hol) and Hol×beef breed bulls (545 g/d) and results reported by Herva et al. (Reference Herva, Virtala, Huuskonen, Saatkamp and Peltoniemi2009) based on results of 55 375 bull calves delivered by Atria Ltd. in 2003 (538 g/d). Compared with the recent Finnish experimental datasets for dairy bulls with typical Finnish grass silage-based diets (Huuskonen & Joki-Tokola Reference Huuskonen and Joki-Tokola2010; Huuskonen Reference Huuskonen2011; Huuskonen et al. Reference Huuskonen, Huumonen, Joki-Tokola and Tuomisto2011), the average lifetime carcass gain was c. 10% lower in the present field data. This difference probably illustrates variable feeding regimes and management factors at farm level compared with the controlled experimental environments. Typically all bull calves transferred from dairy farms are housed and fed consistently in finishing farms, i.e. different methods are not used for pure dairy breeds and dairy×beef crossbred bulls within a finishing farm. Therefore, it can be assumed that the results of the present data give a good representation of the differences between the breed groups in Finnish cattle population.
The superior growth of the dairy×beef breed crosses compared with the pure dairy breeds has been demonstrated in numerous studies (e.g. More O'Ferrall & Keane Reference More O'Ferrall and Keane1990; McGee et al. Reference McGee, Keane, Neilan, Moloney and Caffrey2005; Huuskonen et al. Reference Huuskonen, Pesonen, Kämäräinen and Kauppinen2013). Based on a dataset with purebred Hol and Hol×beef breed bulls, Huuskonen et al. (Reference Huuskonen, Pesonen, Kämäräinen and Kauppinen2013) reported that the average daily carcass gain of the Hol bulls was 542 g/d, and improved by 7, 16, 20, 10, 13 and 17% with Hol×Ab, Hol×Ba, Hol×Ch, Hol×Hf, Hol×Li and Hol×Si crossbreds, respectively, compared with pure Hol bulls. These results are in line with the present study using purebred NR and NR×beef breed crosses. The higher carcass yield of Continental crosses (NR×Li and NR×Ba) over purebred dairy bulls observed in the feeding trial is in agreement with earlier findings (More O'Ferrall & Keane Reference More O'Ferrall and Keane1990; Güngör et al. Reference Güngör, Alçiçek and Önenç2003; McGee et al. Reference McGee, Keane, Neilan, Moloney and Caffrey2005). For example, McGee et al. (Reference McGee, Keane, Neilan, Moloney and Caffrey2005) perceived that carcass yield was significantly higher for Hol×Ch crosses (561 g/kg) than purebred dairy bulls or steers (532 g/kg). Wheeler et al. (Reference Wheeler, Cundiff, Shackelford and Koohmaraie2005) reported that the carcasses from British sire breeds tended to have lower carcass yield than Continental Europe sire breeds at common fat thickness and fat trim percent endpoints.
The fact that there are differences between breed types in conformation and fat scores has been well established in previous datasets (More O'Ferrall & Keane Reference More O'Ferrall and Keane1990; McGee et al. Reference McGee, Keane, Neilan, Moloney and Caffrey2005; Huuskonen et al. Reference Huuskonen, Pesonen, Kämäräinen and Kauppinen2013), and this was also the case in the present large field of data. The better conformation score of the NR×beef crosses compared with pure NR bulls is consistent with Huuskonen et al. (Reference Huuskonen, Pesonen, Kämäräinen and Kauppinen2013), who reported that the conformation score of the Hol bulls improved most (71–78%) by using Ba, Li and Ch sires and less by using Hol×Ab and Hol×Hf crosses (41%) or Hol×Si crosses (54%). Furthermore, the superiority of the NR×Li and NR×Ba crossbred bulls for carcass conformation compared with purebred NR bulls corresponded to the results reported by Keane et al. (Reference Keane, More O'Ferrall and Connolly1989) with Friesian, Friesian×Limousin and Friesian×Blonde d'Aquitaine steers. In addition, Keane & More O'Ferrall (Reference Keane and More O'Ferrall1992) observed that the conformation of Friesian×Hereford and Friesian×Simmental steers was 36 and 40% better than purebred Friesians, respectively. Although measures of carcass fatness generally increase with increasing carcass weight (Keane & Allen Reference Keane and Allen1998), the carcass fat score of the NR×Ba bulls was lower than that of the NR bulls at a constant age in the present study. This is consistent with the results reported by Huuskonen et al. (Reference Huuskonen, Pesonen, Kämäräinen and Kauppinen2013) based on data with purebred Hol and Hol×beef breed bulls. Bartoň et al. (Reference Bartoň, Řehák, Teslík, Bureš and Zahrádková2006) concluded that, in general, the animals of earlier maturing breeds (Hf, Ab) produced relatively more fat than later maturing (Ch, Si) in spite of the fact that they were slaughtered at a significantly lower live weight. This statement is supported by the present data with crossbred bulls.
Considering the average carcass weights in different EUROP conformation and fat score classes, it is obvious that the differences in conformation and fat scores among breed types are not explained solely by carcass weights. In particular, Ba, Ch and Li crosses had better conformation than the NR bulls in the same carcass weight. According to Lawrence et al. (Reference Lawrence, Fowler and Novakofski2012) the body composition of beef breeds is not only dependent on carcass weight. For example, when early-maturing Hf and late-maturing Ba breeds were compared, the relative fatness of both breeds remained quite similar at different weights. Both breeds increased in fatness as the carcass weight increased but the differential remained constant (Lawrence et al. Reference Lawrence, Fowler and Novakofski2012). The different breed bulls are in different stages of their growth path from the beginning of growing till the end of finishing. The mature weight of the late-maturing bulls is greater than the early-maturing bulls, but the tissue composition is also different (Alberti et al. Reference Alberti, Panea, Sañudo, Olleta, Ripoll, Ertbjerg, Christensen, Gigli, Failla, Concetti, Hocquette, Jailler, Rudel, Renand, Nute, Richardson and Williams2008); therefore the body composition (fat v. lean) of late-maturing bulls as adult animals is different to that of the early-maturing bulls.
Market demand in Scandinavia concerning carcass fat is different from those beef markets where marbled beef is favoured (Herva et al. Reference Herva, Huuskonen, Virtala and Peltoniemi2011). Consumers generally favour low-fat products in Finland, and the beef industry has stated that, optimally, two-thirds of the carcasses would have a EUROP fat score of 2 and one-third a EUROP fat score of 3 (Herva et al. Reference Herva, Huuskonen, Virtala and Peltoniemi2011). Lean carcasses are favoured in setting prices. There are penalties for carcasses under 320 kg with fat scores 3–5 and for carcasses over 320 kg with fat scores 4–5. According to the present data, the NR, NR×Ab and NR×Hf bulls would have carcass fat class 3 at carcass weights of c. 350–360 kg, while NR×late-maturing crossbreds would be given this score at carcass weights of c. 385–400 kg. Thus the use of late-maturing rather than early-maturing bulls on NR dairy cows would permit the carcass weight of the progeny to increase 10–15% without an increase in carcass fatness. Alternatively, in recognition of the growing consumer demand for beef with less fat, the fat content of NR×late-maturing carcasses would be lower than that of purebred NR or NR×early-maturing carcasses of similar weight.
The differences in conformation score suggested a superior muscling of the NR×Ab and NR×Hf crosses compared with pure NR bulls. However, in terms of valuable cuts there were only limited differences between NR, NR×Ab and NR×Hf bulls. Instead, NR×late-maturing breed bulls had higher proportions of many high-value joints (rounds, loins) compared with purebred NR bulls. These observations are in line with the results reported by Huuskonen et al. (Reference Huuskonen, Pesonen, Kämäräinen and Kauppinen2013) based on data with purebred Hol and Hol×beef breed bulls. Previously, Keane (Reference Keane2011) concluded that early-maturing beef breeds and their crosses typically have more fat and less muscle than both pure dairy breeds and late-maturing beef breeds and their crosses. Furthermore, pure dairy breeds have typically more fat and less muscle than late-maturing beef breeds and their crosses (Keane Reference Keane2011). Other studies have also shown that Continental breed type cattle have more of their muscle in the higher-value joints than British breed crosses and pure dairy breeds (Keane et al. Reference Keane, More O'Ferrall and Connolly1989, Reference Keane, More O'Ferrall, Connolly and Allen1990; Keane & More O'Ferrall Reference Keane and More O'Ferrall1992).
In the feeding trial no differences in DM or energy intakes between breed groups were observed, which contrasts with some previously reported findings. For example, Cummins et al. (Reference Cummins, Keane, O'Kiely and Kenny2007) reported that Friesian steers had higher silage DM intake than the beef-cross animals and, as a consequence, had higher total DM and net energy intakes over the entire finishing period. The higher silage and total DM intakes of the pure dairy animals were also observed by P. D. O'Brien (personal communication 1997) for comparisons of both Holstein and Friesian steers with Friesian×Charolais steers and Keane & Allen (Reference Keane and Allen2002) for comparisons of Friesian–Holstein with Friesian–Holstein×Piedmontese and Friesian–Holstein×Romagnola steers. The results from the literature mentioned above demonstrate that growing dairy breed cattle have a higher intake than beef breeds when the diet is forage-based. It is stated that dairy breeds have a higher intake than beef breeds because the genetic selection for higher milk yield has resulted in dairy animals having a larger gastrointestinal tract (Geay & Robelin Reference Geay and Robelin1979) and a higher feed intake capacity (Langholz Reference Langholz1990).
With forage-based diets, dairy breeds can express their higher intake capacity because forage intake is mainly regulated by physical constraints such as rumen fill (Illius & Gordon Reference Illius and Gordon1991). However, it is less clear if this also applies for diets based on concentrates. In the present feeding trial, the amount of the diet made up of concentrate was 500 g/kg DM, and the high carcass growth rates measured imply that the feed ration was of very good quality. This suggested a physiological regulation of feed intake instead of a physical regulation in the present trial. Generally, when cattle are fed high-energy rations that are palatable, low in fill and readily digested, feed intake is regulated to meet the energy demands of the animal, unless the diet is fermented too rapidly and digestive disorders occur (Forbes Reference Forbes2007), which was not likely in the present experiment. Therefore, it is possible that with concentrate-based rations, dairy breeds may not express their greater rumen fill capacity because in this situation, intake is more likely to be determined by metabolic constraints related to the animal's ability to utilize absorbed nutrients (Illius & Jessop Reference Illius and Jessop1996).
Cummins et al. (Reference Cummins, Keane, O'Kiely and Kenny2007) observed that when the animals on the varied feeding pattern moved to ad libitum concentrates, DM intake continued to be numerically higher for the Friesians compared with beef crosses (7·72 v. 7·56 kg/d) but the difference was much less than for silage DM intake (6·64 v. 6·22 kg/d). For the entire 164-day finishing period, silage intake was proportionately 0·085 higher for Friesians than for beef crosses on the varied feeding pattern whereas total concentrate intake was only proportionately 0·010 higher (Cummins et al. Reference Cummins, Keane, O'Kiely and Kenny2007). Thus, the difference between the breeds in intake capacity was greater on silage than on concentrates. Therefore, in the present experiment, the high-energy ration used was perhaps the reason that no differences in intake parameters between breed groups were observed. A limitation of the feeding experiment is that only nine animals per breed group were examined. Therefore, the inconclusive differences in the fattening performance parameters presented could also be partly due to the low numbers of animals in the breed groups.
In conclusion, the large dataset collected in the current study describes the growth and carcass traits of slaughtered bulls in the Finnish NR cattle population well. Improvements in beef production traits obtained by crossbreeding NR cows with beef breed sires are highly dependent on the choice of sire breed. Crossbreeding with late-maturing beef breeds (Ba, Ch, Li, Si) had favourable effects both on daily carcass gain and carcass quality traits (conformation, proportion of high-value joints) of the progeny when compared with purebred NR bulls. The effects of crossbreeding NR cows with Ab or Hf sires were variable. No advantages in proportion of high-value joints seemed to be obtained by crossbreeding NR cows with these early-maturing breeds, while the improvements in daily carcass gain and carcass conformation score were intermediate compared with the late-maturing crossbreds. Crossbreeding, especially with late-maturing bulls, largely improved carcass production compared with purebred NR bulls. The feeding experiment indicated that there is no difference in DM intake between pure NR and crossbred bulls when animals are fed with high-energy rations. Therefore, differences in growth and carcass traits described well the economic superiority of crossbreds compared with pure dairy bulls from beef producers’ point of view.
This study was a part of the cooperation between MTT Agrifood Research Finland and Savonia University of Applied Sciences to find ways to develop and improve milk and beef production in Finland. The study was partially funded by the Centre for Economic Development, Transport and the Environment for North Savo, A-Tuottajat Ltd., HK-Agri Ltd., Saarioinen Lihanjalostus Ltd., Snellman Lihanjalostus Ltd. and Valio Ltd. We wish to express our gratitude to Mr. Matti Huumonen and his personnel for technical assistance and their excellent care of the experimental animals. We would like to thank Ms. Maarit Hyrkäs for the data processing and statistical analyses. The personnel at Animal Production Research in Jokioinen are thanked for the laboratory analyses. The evaluation of the manuscript by Professor Marketta Rinne is warmly acknowledged.
