437 research outputs found

    A comparison of finishing strategies to fixed slaughter weights for Holstein Friesian and Belgian Blue × Holstein Friesian steers

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    peer-reviewedCattle finishing strategies may involve feeding a high energy diet throughout or following a period of moderate growth. The objective of this study was to compare Holstein Friesian (HF) and Belgian Blue × Holstein Friesian (BB) steers (24 per breed type, initial live weight 434 and 431 kg for HF and BB, respectively) finished to 560 kg or 620 kg target slaughter weight, on either a concentrate diet ad libitum from the start of the finishing period (C), or on a concentrate diet ad libitum following an 84-day period on grass silage (SC). Slaughter weights were similar for HF and BB, but kill-out proportion, carcass weight and carcass conformation class were superior (P < 0.001), and carcass fat score was inferior (P < 0.001), for BB. Total concentrate, dry matter and net energy intakes were higher (P < 0.001) for HF, and efficiency of utilization of net energy for carcass-weight gain was lower (P < 0.01). Mean daily live-weight gain was higher for C than SC (P < 0.001) and for slaughter at 560 kg than at 620 kg (P < 0.05). Killout proportion was higher for C than SC (P < 0.05) and for 620 kg compared to 560 kg slaughter weight (P < 0.001). Measures of fatness were unaffected by feeding treatment but all were higher (P < 0.01) for the 620 kg slaughter weight. Net energy required per unit carcass-weight gain was higher for C than SC (P < 0.001) and for 620 kg than for 560 kg slaughter weight (P < 0.001). When slaughtered at 620 kg live weight there was no difference between the feeding treatments in net energy required per unit carcass-weight gain. While both breed types had similar live-weight gain BB had 9% greater (P < 0.01) carcass-weight gain and were 14% more efficient (P < 0.01) in converting feed energy to carcass weight. Neither breed type had commercially acceptable carcasses at 560 kg slaughter weight when finished on SC

    Ranking of Sire Breeds and Beef Cross Breeding of Dairy and Beef Cows

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    End of Project ReportSummary There is general agreement across countries on the ranking of beef breeds for production and carcass traits. Differences between dairy and early maturing beef breeds in growth and slaughter traits are small, but the latter have lower feed intake and better carcass conformation. Late maturing beef breeds also have lower feed intake and better carcass conformation and in addition, have a higher growth rate, kill-out proportion and carcass muscle proportion. When factors such as age and fatness are accounted for, differences between breeds in meat quality traits are small. Differences amongst breed types in kill-out proportion can be explained by differences in gut contents (consequent on differences in feed intake), differences in the proportions of gastrointestinal tract and metabolic organs, differences in hide proportion, and differences in offal fats. Growth is an allometric, rather than an isometric, process. Some parts, organs and tissues grow relatively more slowly than the animal overall, and so become decreasing proportions over time, while others grow relatively faster and become increasing proportions. With increasing slaughter weight, the proportions of non carcass parts, hind quarter, bone, total muscle and higher value muscle decrease, while the proportions of non carcass and carcass fats, fore quarter and marbling fat all increase. Because of heterosis or hybrid vigour, the productivity of cross-bred cattle is superior to the mean of the parent breeds. While calving difficulty may be slightly higher (probably due to greater birth weight), calf mortality is much reduced in cross-breds. In addition, general robustness and growth rate are increased. There are additive effects of heterosis in the dam and the progeny. When cross-bred cows are mated to a bull of a third breed, >60 % of total heterosis is attributable to the cross-bred cows. The double muscling phenotype in beef cattle is due to the inactivated myostatin gene, but the inactivating mutation is not the same in all breeds and other genes also contribute to muscling. Compared to normal animals, double muscled animals have lower proportions of digestive tract, internal fats and metabolic organs. This explains their superior kill-out proportion. They also have a smaller hind shin that helps accentuate the muscling in the remainder of the 4 limb. There are similar degrees of muscular hypertrophy in both the hind and fore quarters. Muscle to bone ratio is about one third greater in double muscled than in normal carcasses. Piedmontese cattle with none, one or two mutated myostatin alleles were compared with normal Herefords and Limousins. In the absence of any mutated allele, Piedmontese were similar to Herefords, with one mutated allele they were similar to Limousins and with two mutated alleles they were immensely superior to Limousins. In fact, the response to the second mutated allele was about three times that to the first. If progeny approximated to the mean of the parent breeds, crossing a double muscled sire with a dairy or early maturing beef cow would result in cattle of similar characteristics to pure-bred late maturing beef breeds. This does not happen because double muscling is dependent on a homozygous myostatin genotype. The progeny of a common cow breed and normal late maturing, or double muscled, sire breeds have similar production traits

    Performance and carcass traits of progeny of Limousin sires differing in genetic merit

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    peer-reviewedGenetic indices for growth and carcass classification are published for beef sires used in Ireland for artificial insemination (AI). The objective of this study was to compare growth and carcass traits of progeny of Limousin sires of low and high genetic index for growth. A total of 70 progeny (42 males and 28 females) out of predominantly Holstein-Friesian cows by 7 AI Limousin sires were reared together to slaughter. The 7 sires were classified as low (n=3) or high (n=4) index based on their published genetic index for growth. The male progeny were reared entire and all animals were slaughtered at about 20 months of age. Carcasses were classified for conformation and fatness, and a rib joint (ribs 6 to 10) was separated into fat, muscle and bone. Growth rate did not differ significantly between the index groups but tended to be higher for the high index progeny. This higher growth rate, combined with a significantly higher kill out proportion, resulted in carcass weight andcarcass weight per day of age being significantly higher for the high index progeny. Carcass conformation and fat class were not affected by genetic index, nor was the composition of the rib joint. Compared with males, females had a significantly lower growth rate and kill out proportion and, consequently, had a significantly lower carcass weight. The proportions of fat and bone in the rib joint were significantly higher, and the proportion of muscle was significantly lower for females than for males. It is concluded that carcass weight reflected sire group genetic index for growth but feed intake, carcass classification and rib joint composition were not affected

    Evaluation of the Progeny of Beef Sires Differing in Genetic Merit

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    End of project reportThe Irish Cattle Breeding Federation (ICBF) publishes breeding values (BVs) for beef bulls. Historically, BVs were expressed in index form relative to the base population. Sometime ago this changed to expression in units of measurement of trait. This change occurred in the course of this project and was accompanied by some re-ranking of bulls. BVs are published for growth, carcass grades and calving traits. Growth BV is expressed as carcass weight but there is no indication if this results from higher live weight gain or from a higher kill-out proportion and there is no indication of any consequences for feed intake or efficiency. • The objectives of the project were (i) to compare progeny of bulls of high and low growth genetic index, for growth, feed intake, slaughter traits and carcass traits, (ii) to partition the extra live weight of progeny of high growth index bulls into carcass and non-carcass parts, and (iii) to partition any extra carcass weight of progeny from high growth index bulls into its component fat, muscle and bone fractionsEuropean Unio

    Post-weaning performance and carcass characteristics of steer progency from different suckler cow breed types

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    peer-reviewedIn two experiments a total of 44 steer progeny of spring-calving Charolais (C) and Hereford × Friesian (HF) suckler cows and C sires were slaughtered at approximately 2 years of age. Following weaning they were offered silage and 1 kg of concentrate per head daily during a 5 month winter after which they spent 7 months at pasture. In Experiment 1, animals were given a silage/concentrate diet during a finishing period of either 95 or 152 days. In Experiment 2, steers were offered either a daily diet of silage plus 6 kg of concentrates or concentrates to appetite plus 5 kg of silage (fresh weight) during the final 140-day finishing period. Following slaughter, an 8-rib pistola from each animal was dissected. For the two experiments combined C and HF progeny had carcass weights of 372 and 385 (s.e. 6.1) kg, proportions of carcass as pistola of 467 and 454 (s.e. 2.8) g/kg and pistola meat proportions of 676 and 642 (s.e. 5.1) g/kg, respectively. All fat traits were lower for the C than HF progeny but there was no difference in carcass conformation score. Increasing slaughter weight increased carcass weight (P < 0.001), kidney plus channel fat weight (P < 0.001), and pistola fat proportion (P < 0.001) and decreased the proportions of carcass as pistola (P < 0.05), pistola meat (P < 0.01), and bone (P < 0.05). In conclusion, breed type had no effect on carcass growth but the C progeny had higher meat yield than the HF. Increasing slaughter weight increased fatness and reduced meat yield

    Comparison of pasture and concentrate finishing of Holstein Friesian, Aberdeen Angus × Holstein Friesian and Belgian Blue × Holstein Friesian steers

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    peer-reviewedCrossbreeding Holstein Friesian dairy cows with both early and late maturing beef breed bulls is common in Ireland. This study concerned the comparison of spring-born Holstein Friesian (HF), Aberdeen Angus × Holstein Friesian (AA) and Belgian Blue × Holstein Friesian (BB) steers slaughtered directly off pasture in the autumn or following a period of concentrate finishing indoors. Male calves (18 per breed type) were reared together until August of their second year when they were assigned to a 3 (breed type) × 3 (finishing strategy) factorial experiment. The three finishing strategies were (i) pasture only for 94 days to slaughter (PE), (ii) concentrate ad libitum indoors for 94 days to slaughter (CE), and (iii) pasture only for 94 days followed by concentrate ad libitum indoors for 98 days to slaughter (PC). For HF, AA, and BB, mean carcass weight, carcass conformation score and carcass fat score values were 275, 284 and 301 (s.e. 5.1) kg, 1.75, 2.42 and 2.89 (s.e. 0.11), and 2.48, 2.89 and 2.17 (s.e. 0.11), respectively. Pasture alone supported live-weight and carcass-weight gains of approximately 800 g/day and 400 g/day, respectively. Live-weight and carcass-weight gains on concentrate ad libitum were approximately 1400 and 870 g/day, respectively. For PE, CE and PC, mean carcass weight, carcass conformation score and carcass fat score values were 244, 287 and 329 (s.e. 5.1) kg, 1.81, 2.56 and 2.69 (s.e. 0.11), and 1.83, 2.71 and 3.01 (s.e. 0.11), respectively. It is concluded that none of the breed types reached an acceptable carcass weight on PE and only HF had acceptable carcass finish. All breed types were acceptably finished on both concentrate finishing strategies

    Effects of feeding management and breed type on muscle chemical composition and relationships between carcass and muscle compositional traits in steers

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    peer-reviewedThere is little published information on the chemical composition of muscle from beef steers produced in Irish production systems. The objective of this study was to determine the effects of feeding management and breed type on m. longissimus chemical composition of steers, and to examine relationships between selected carcass traits and measures of carcass and muscle composition. A total of 117 steers (65 Friesians and 52 Charolais Friesians) were assigned on weight within breed type to a pre-experimental slaughter group and to one of 12 finishing groups (6 feeding treatments by 2 finishing periods). The 6 feeding treatments were: (1) silage only offered ad libitum (SO), (2) and (3) SO plus a low concentrate level, (4) and (5) SO plus a high concentrate level, (6) concentrates ad libitum. In Treatments 2 and 4, the silage and concentrates were offered separately whereas in Treatments 3 and 5 they were offered as a total mixed ration (TMR). The two finishing periods were 105 and 175 days. Mean low, high and ad libitum concentrate levels were proportionately 0.415, 0.732 and 0.927, respectively, of daily dry matter intake. Carcass weight, fat depth, fat proportion in the rib joint and m. longissimus lipid concentration all increased (P < 0.01) asymptotically with increasing concentrate level. Carcass fat class (P < 0.07), perinephric plus retroperitoneal fat weight (P < 0.001), fat depth (P < 0.06), fat proportion in the rib joint (P < 0.001) and m. longissimus lipid concentration (P < 0.001) were higher for Friesians than for Charolais crosses. Carcass weight increased (P < 0.001) with increased duration of the finishing period, as did carcass fat class (P < 0.06), fat proportion in the rib joint (P < 0.001) and m. longissimus lipid concentration (P < 0.001). Method of feeding had no effect on any of the traits measured

    Optimising The Response To Supplementary Concentrates By Beef Cattle In Winter

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    End of project reportConcentrates are a major component of feed costs in winter finishing of beef cattle. Two separate experiments were carried out to evaluate the response to increasing supplementary concentrate level with grass silage and the effects of feeding the silage and concentrates separately or as a total mixed ration (TMR). In experiment 1, a total of 117 finishing steers (initial live weight 538 kg, s.d. 35.5) were assigned to a preexperimental slaughter group of 9 animals and to 6 feeding treatments of 18 animals each. The feeding treatments were: 1) silage (SO) only offered ad libitum, 2) SO plus a low level of concentrates offered separately (LS), 3) SO plus a low level of concentrates offered as a TMR (LM), 4) SO plus a medium level of concentrates offered separately (MS), 5) SO plus a medium level of concentrates offered as a TMR (MM), and 6) concentrates ad libitum plus a restricted silage allowance (AL). Low and medium target concentrate levels were 3 and 6 kg dry matter (DM) per head daily. When silage and concentrates were fed separately, the daily concentrate allowance was given in one morning feed. The animals were individually fed for a mean period of 132 days. After slaughter, carcasses were weighed and graded and the ribs joint was dissected into its component tissues. Silage DM intake decreased but total DM intake increased with increasing concentrate level. Live weight gains for SO, LS, LM, MS, MM and AL were 0.34, 0.86, 0.86, 1.02, 1.00 and 1.12 (s.e. 0.064) kg/day, respectively. Corresponding carcass weight gains were 0.25, 0.58, 0.58, 0.71, 0.68 and 0.82 (s.e. 0.028) kg/day. All measures of fatness increased, ribs joint bone proportion decreased, and muscle proportion was not significantly affected by dietary concentrate level. There were no significant interactions between concentrate level and method of feeding. Compared with offering the feeds separately, feeding a TMR increased silage DM intake by proportionately 0.06 and total DM intake by proportionately 0.04. Otherwise, method of feeding had no significant effect on performance, slaughter or carcass traits. Mean rumen pH decreased while ammonia concentration tended to increase with increasing concentrate level. Total volatile fatty acids and the acetate to propionate ratio were lowest for SO. Method of feeding had no significant effect on rumen fermentation
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