scholarly journals Meat quality and the calpain system of feedlot steers following a single generation of divergent selection for residual feed intake

2001 ◽  
Vol 41 (7) ◽  
pp. 1013 ◽  
Author(s):  
M. B. McDonagh ◽  
R. M. Herd ◽  
E. C. Richardson ◽  
V. H. Oddy ◽  
J. A. Archer ◽  
...  

Residual feed intake (RFI) is calculated as the difference between an animal’s actual feed intake and its expected feed intake based on its size and growth over a specified test period. Following a single generation of divergent selection for postweaning RFI, Angus steers and Angus × Hereford, Angus×Poll Hereford and Angus × Shorthorn crossbred steers born in 1996 and 1997 were fed in a feedlot. Cohorts of steers were slaughtered at the same age and had attained similar (P&gt;0.05) final liveweights: 467 kg for steers selected for low RFI (high efficiency; HE, n = 91) and 459 kg for steers selected for high RFI (low efficiency; LE, n = 98). The HE and LE steers had similar (P>0.05) carcass weight (247 and 244 kg), dressing percentage (53.1 and 53.2&percnt;) and eye-muscle area (58.9 and 60.3 cm 2 ). The HE steers had slightly less subcutaneous fat over the rib than the LE steers (9.2 v. 10.1 mm, P&lt;0.05), and there was a trend towards less fat over the rump of HE steers (11.5 v. 12.1 mm, P = 0.10). For meat samples taken from the M. longissimus dorsi (LD) there were no differences (P>0.05) between the HE and LE steers in content of intramuscular fat (5.4 and 5.3% fresh weight), marbling scores, meat colour and fat colour. There were also no differences (P>0.05) between HE and LE steers in shear force and compression values for samples of LD aged for 1 day (4.6 and 4.6 kg shear force, 1.45 and 1.44 kg compression), or for 14 days (3.8 and 3.5 kg, 1.36 and 1.32 kg). Myofibril fragmentation index (MFI) measures the breakdown of these structural elements which occurs as an initial step in the process of protein degradation and meat tenderisation. MFI was lower (i.e. less fragmentation; P<0.05) in LD samples from HE steers than from LE steers, both in samples aged for 1 day (67.7 v. 72.5 units) and in samples aged for 14 days (87.8 v. 91.1 units). The rate of decline in MFI between 1 and 14 days post slaughter was similar in the LD samples from both lines of steers. There were no differences (P>0.05) between HE and LE steers in the activity of m-calpain and &micro;-calpain in LD immediately after slaughter (HE steers: 1.9 and 2.3 units, LE steers: 1.8 and 2.1 units). The level of calpastatin in LD from the HE steers was 13% higher than in the LD from the LE steers (5.2 and 4.6 units respectively, P<0.05). Rate of myofibril fragmentation was positively correlated (P<0.01) with the ratios of both m-calpain and µ-calpain to calpastatin, but not (P>0.10) with levels of either calpain or calpastatin. A single generation of divergent selection for RFI produced differences in calpastatin and myofibril fragmentation that may, with on-going selection for low RFI, negatively affect meat tenderness.


2018 ◽  
Vol 58 (1) ◽  
pp. 43 ◽  
Author(s):  
M. Laurence ◽  
J. M. Accioly ◽  
K. J. Copping ◽  
M. P. B. Deland ◽  
J. F. Graham ◽  
...  

This paper reports a subset of results from the Beef Cooperative Research Centre-funded Maternal Productivity Project. This research aimed to describe the response of Angus cows of different and divergent genotypes to variable nutritional environments over five breeding seasons. Cows selected for a divergence in either fat depth (HFat vs LFat) or residual feed intake (RFI: HRFI vs LRFI) based on mid-parent estimated breeding values (EBV) for those traits were allocated in replicate groups to either high or low nutritional treatments at two different sites, namely the Vasse Research Centre in Western Australia and the Struan Research Centre in South Australia. The traits reported in this paper include output traits (birth and weaning weight of calves, liveweight change of cows), change traits (change in Rib Fat, P8 fat, eye muscle area and liveweight between specified time points) and reproductive traits [pregnancy rates, percentage calves born alive and days to calving at the days to calving at the second calving opportunity (DC2)]. Having had their first calf, the vulnerability of these young cows to nutritional restriction and how it may adversely affect rebreeding was examined. HFat and HRFI cows were fatter, heavier and had greater eye muscle area than LFat and LRFI, respectively, at all times during the breeding cycle on both levels of nutrition. There was no difference in either days-to-calving or pregnancy rates after the second mating between genotypes. Equally, nutritional treatment had no effect on these traits in this cohort of cows. There was evidence for an implied genetic correlation between Rib Fat EBV, DC2 and pregnancy rates of –0.38 that suggests that selection for leanness may result in reduced fertility of the herd but the effect was not significant herein. As long as producers record the phenotype for both traits and select cows with favourable DC2 as well as low fatness, these problems can be avoided, owing to only 22% of variation in pregnancy rates being explained by DC2 and Rib Fat EBV. Producers can largely be confident that selection for leanness, or increased feed efficiency, has little impact on productivity as long as cows are in adequate body condition to remain healthy and productive.



2005 ◽  
Vol 45 (8) ◽  
pp. 985 ◽  
Author(s):  
P. F. Arthur ◽  
R. M. Herd ◽  
J. F. Wilkins ◽  
J. A. Archer

Data on 185 Angus cows were used to study the effect of divergent selection for residual feed intake on maternal productivity across 3 mating seasons, starting from 2000. The cows were the result of 1 to 2.5 generations of selection (mean of 1.5), and differed in estimated breeding value for residual feed intake by 0.8 kg/day. In general, cows lost subcutaneous fat (measured 2 times a year) during the period when they were nursing calves, and gained fat thereafter. No significant selection line differences in fatness were observed except for those measured at the start of the 2000 (10.8 ± 0.4 v. 9.3 ± 0.4 mm), 2001 (11.3 ± 0.4 v. 9.8 ± 0.4 mm) and 2002 (7.0 ± 0.5 v. 5.7 ± 0.5 mm) mating seasons, where high residual feed intake cows had significantly (P<0.05) higher rib fat depths. No significant selection line differences in weight (measured 4 times a year) were observed. However, the cows either maintained or lost weight during the calf nursing period, and gained weight thereafter, with mean weights ranging from 450 to 658 kg. There were no significant selection line differences in pregnancy (mean 90.4%), calving (mean 88.7%) and weaning (mean of 80.8%) rates, milk yield (mean 7.7 kg/day) and weight of calf weaned per cow exposed to bull (mean 195 kg). The study indicates that after 1.5 generations of divergent selection for residual feed intake there are no significant selection line differences for maternal productivity traits.



2016 ◽  
Vol 94 (suppl_2) ◽  
pp. 108-109 ◽  
Author(s):  
D. J. Hewitt ◽  
C. F. M. de Lange ◽  
T. Antonick ◽  
J. C. M. Dekkers ◽  
A. R. Pendleton ◽  
...  


1995 ◽  
Vol 46 (4) ◽  
pp. 703
Author(s):  
PA Kenney ◽  
ME Goddard ◽  
LP Thatcher

Three and a half thousand lambs from Border Leicester x Merino ewes mated to 133 sires from five Poll Dorset, one White Suffolk, one Siromt, two Meridale and four Merino studs were slaughtered, their carcasses halved and one side divided into six primals. Subcutaneous fat was dissected from all six primals, and bone from only the three rear primals. There were four slaughter groups: average slaughter weights of 30 and 35 kg for ewes and 35 and 45 kg for cryptorchids. Heritabilities and phenotypic and genetic correlations for all traits measured (>50) are published in an appendix. Where comparisons were available, estimates were similar to those for purebred animals. Genetic parameters for various assessments of fat were similar except for channel and omental fat. The GR fat depth was the best predictor for total subcutaneous fat, cannon bone length for total bone, and eye muscle area for total soft tissue. Carcass weight and GR appear to be the most important measurements for use in selection for breeding of sires for the prime lamb industry. Slaughter weight and fat depth at the C site could be used as suitable alternatives on live animals. Production of lean meat is not likely to be increased greatly by including measurements other than liveweight and GR in a selection index. Of the other measurements bone length and eye muscle measurements showed most promise.



2014 ◽  
Author(s):  
Emily Arkfield ◽  
Emily Hamman ◽  
Jordy E. Berger ◽  
Roger Johnson ◽  
Jennifer Young ◽  
...  


Meat Science ◽  
2014 ◽  
Vol 96 (1) ◽  
pp. 470
Author(s):  
E.K. Arkfeld ◽  
E.R. Benedict ◽  
R.C. Johnson ◽  
J.M. Young ◽  
J.F. Patience ◽  
...  


2014 ◽  
Vol 54 (5) ◽  
pp. 550 ◽  
Author(s):  
W. Al-Husseini ◽  
C. Gondro ◽  
K. Quinn ◽  
L. M. Cafe ◽  
R. M. Herd ◽  
...  

Hormonal growth promotants (HGP) have been used to improve feed conversion ratio (FCR) and growth rates of cattle by modifying protein turnover rates. Residual feed intake (RFI) is correlated with FCR and has been adopted in Australia as a measure of feed efficiency in cattle for the purpose of genetic improvement. Eight genes (AHSG, GHR, GSTM1, INHBA, PCDH19, S100A10, SERPINI2 and SOD3) have been previously reported to be highly associated with RFI and could potentially be used to predict RFI in bulls and steers. In this study, expression levels of these genes in liver tissue of 46 cattle were measured by quantitative real-time PCR. These cattle were part of a larger tenderness gene marker experiment consisting of two breeds (Angus and Brahman); two sexes (steers and heifers) and HGP treatments (implanted vs control). Cattle were measured for growth, feed efficiency, body composition and carcass traits. Results showed the expression of these eight genes was significantly correlated with RFI. However, HGP treatment did not affect RFI or the expression of the RFI-associated genes. HGP treatment increased average daily gain by 20%, improved FCR by 18%, and increased rib eye-muscle area by 7.5%. HGP treatment was effective in improving growth rate, presumably by its known action in the protein turnover mechanism. This mechanism has been hypothesised as one of the regulators of RFI. Lack of effect of HGP treatment on RFI does not support this hypothesis.



2012 ◽  
Vol 90 (4) ◽  
pp. 1097-1108 ◽  
Author(s):  
H. Gilbert ◽  
J.-P. Bidanel ◽  
Y. Billon ◽  
H. Lagant ◽  
P. Guillouet ◽  
...  


1995 ◽  
Vol 46 (4) ◽  
pp. 703
Author(s):  
PA Kenney ◽  
ME Goddard ◽  
LP Thatcher

Three and a half thousand lambs from Border Leicester x Merino ewes mated to 133 sires from five Poll Dorset, one White Suffolk, one Siromt, two Meridale and four Merino studs were slaughtered, their carcasses halved and one side divided into six primals. Subcutaneous fat was dissected from all six primals, and bone from only the three rear primals. There were four slaughter groups: average slaughter weights of 30 and 35 kg for ewes and 35 and 45 kg for cryptorchids. Heritabilities and phenotypic and genetic correlations for all traits measured (>50) are published in an appendix. Where comparisons were available, estimates were similar to those for purebred animals. Genetic parameters for various assessments of fat were similar except for channel and omental fat. The GR fat depth was the best predictor for total subcutaneous fat, cannon bone length for total bone, and eye muscle area for total soft tissue. Carcass weight and GR appear to be the most important measurements for use in selection for breeding of sires for the prime lamb industry. Slaughter weight and fat depth at the C site could be used as suitable alternatives on live animals. Production of lean meat is not likely to be increased greatly by including measurements other than liveweight and GR in a selection index. Of the other measurements bone length and eye muscle measurements showed most promise.



animal ◽  
2017 ◽  
Vol 11 (9) ◽  
pp. 1427-1439 ◽  
Author(s):  
H. Gilbert ◽  
Y. Billon ◽  
L. Brossard ◽  
J. Faure ◽  
P. Gatellier ◽  
...  


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