Divergent genotypes for fatness or residual feed intake in Angus cattle. 3. Performance of mature cows

2018 ◽  
Vol 58 (1) ◽  
pp. 55 ◽  
Author(s):  
K. J. Copping ◽  
J. M. Accioly ◽  
M. P. B. Deland ◽  
N. J. Edwards ◽  
J. F. Graham ◽  
...  
Keyword(s):  
Body Composition ◽  
Pregnancy Rate ◽  
Feed Intake ◽  
Residual Feed Intake ◽  
Reproductive Rate ◽  
Cattle Production ◽  
High Fat ◽  
Angus Cattle ◽  
Selection For ◽  
Estimated Breeding Values

This experiment evaluated the productivity of 500 Angus cows that differed in genetic merit for either subcutaneous rib fat depth (Fat) or residual feed intake (RFI) based on estimated breeding values (EBVs) and managed under two levels of nutrition. Reproductive rate over four calving opportunities in mature cows and growth performance of progeny to weaning was assessed. Level of nutrition significantly affected all body composition traits for both Fat and RFI line cows. Cows on High-Nutrition were 14–16% heavier (P < 0.001) than those on Low-Nutrition. Differences in EBVs for fatness were reflected in phenotypic fatness at maturity. High-RFI line cows were fatter for both scanned rump (P8) and rib (RIB) fat depth relative to their Low-RFI contemporaries. Of those cows that were lactating, there was no significant effect of line or nutrition on pregnancy rate or days to calving (DC). There was, however, a trend (P < 0.1) in the Low-Fat line cows towards longer DC compared with the High-Fat line cows. There was no significant effect of either line or nutrition on calf birthweight. Calves with mothers on High-Nutrition were 8% heavier at weaning (P < 0.001) than those on Low-Nutrition. Lower EBVs for RFI was associated with higher 200-day growth EBV and heavier calves at weaning. Current carcass BREEDPLAN EBVs can be used to select for changes in cow body composition if desired. In this experiment, Angus cows selected for lower RFI or with below-average fatness EBV and had raised a calf at every previous opportunity were not compromised in pregnancy rate or DC at maturity under varying nutrition such as can be experienced during normal seasonal conditions in southern Australia. However, selection for lower RFI was associated with lower weaning rate (P < 0.05), which warrants further investigation to confidently predict the implications for commercial cattle production.

Divergent breeding values for fatness or residual feed intake in Angus cattle. 5. Cow genotype affects feed efficiency and maternal productivity

2018 ◽  
Vol 58 (1) ◽  
pp. 80 ◽  
Author(s):  
M. L. Hebart ◽  
J. M. Accioly ◽  
K. J. Copping ◽  
M. P. B. Deland ◽  
R. M. Herd ◽  
...  
Keyword(s):  
Weight Gain ◽  
Feed Intake ◽  
Feed Efficiency ◽  
Residual Feed Intake ◽  
Bodyweight Gain ◽  
High Fat ◽  
Low Fat ◽  
Weaning Weight ◽  
Angus Cattle ◽  
Selection For

Cow bodyweight gain, calf weaning weight, feed intake and maternal productivity of 500 Angus cows, in 64 replicate groups, were measured over three parities at two locations (Struan and Vasse) as part of the Beef CRC Maternal Productivity Project. The cows were sourced as heifers from the top and bottom 10% of BREEDPLAN Rib Fat EBV (High-Fat and Low-Fat), and from High and Low residual feed intake (RFI) selection lines (High-RFI and Low-RFI). Each of the four genotypes were run under High- and Low-Nutrition (measured as feed on offer) at both sites. The High-Fat cows were 7% more efficient at producing weaner calves under Low-Nutrition than were the Low-Fat cows. This was driven primarily by the 4% difference between the lines in weaning rate. When weaning rate differences were accounted for (as covariate), there was no difference between the Fat lines in the efficiency of weaner weight production. When the weight gain of the cow was included as an output in addition to calf weaning weight, there was also no difference between the Fat lines in efficiency. Low-RFI cows were always more efficient at producing weaner calves than were the High-RFI cows. This was primarily driven through a 7% reduction in annual feed intake (across both nutrition treatments). However, the Low-RFI cows were leaner, had 6.3% lower weaning rate and calved on average 5.4 days later than did the High-RFI cows. Furthermore, the largest differences in feed intake were in spring when feed availability is greatest. In the context of the results herein, a balanced breeding program should include selection for improved reproduction and low RFI.

Divergent genotypes for fatness or residual feed intake in Angus cattle. 7. Low-fat and low-RFI cows produce more liveweight and better gross margins than do high-fat and high-RFI cows when managed under the same conditions

2018 ◽  
Vol 58 (1) ◽  
pp. 103
Author(s):  
L. Anderton ◽  
J. M. Accioly ◽  
K. J. Copping ◽  
M. P. B. Deland ◽  
M. L. Hebart ◽  
...  
Keyword(s):  
Feed Intake ◽  
Residual Feed Intake ◽  
Low Fat ◽  
Gross Margin ◽  
Breeding Values ◽  
Angus Cattle ◽  
Estimated Breeding Values ◽  
Supplementary Feed ◽  
Gross Margins ◽  
Stocking Rates

The present paper focuses on the economic evaluation of the observed differences in maternal productivity of different genetic lines in Angus cattle that were managed under contrasting nutritional regimes typical of southern Australia. Five hundred Angus cows were managed concurrently at two locations in southern Australia. On each site, the cows were managed under the following two different nutritional treatments: High and Low, to simulate different stocking rates. Cows selected for a divergence in either carcass rib-fat depth or residual feed intake based on mid-parent estimated breeding values for those traits, were allocated in replicate groups to either High- or Low-nutrition treatments. By design, the supplementary feeding regime was the same for the High and Low genetic lines to ensure genetic differences were not confounded with management differences. Animal productivity results from the experiment were used as input data to evaluate the economic performance of the four genetic lines under the two nutritional treatments. Two methods were used; the first was a gross-margin calculation of income minus variable costs as AU$ per breeding cow for a 1000-cow herd; the second was a whole-farm linear programming model maximising the gross margin. Stocking rates were optimised by matching the energy requirements for the whole herd with the energy available from pasture and supplementary feed on a representative 700-ha farm. Using the two methods of calculating gross margin (per cow and optimised per hectare), including examination of sensitivity to changes in prices of cattle and supplementary feed, the present study demonstrated that genetically leaner cows due to selection of low fat or low residual feed intake, had gross margins superior to those of genetically fatter cows. They generated more income by selling more liveweight due to heavier weights and higher stocking rates. The results are affected by the management system utilised and some confounding with growth (leaner genetic lines had higher growth estimated breeding values), but will assist producers to make more informed decisions about how to manage animal breeding and nutritional interactions.

Divergent breeding values for fatness or residual feed intake in Angus cattle. 4. Fat EBVs’ influence on fatness fluctuation and supplementary feeding requirements

2018 ◽  
Vol 58 (1) ◽  
pp. 67
Author(s):  
J. M. Accioly ◽  
K. J. Copping ◽  
M. P. B. Deland ◽  
M. L. Hebart ◽  
R. M. Herd ◽  
...  
Keyword(s):  
Feed Intake ◽  
Residual Feed Intake ◽  
Supplementary Feeding ◽  
Genetic Line ◽  
High Fat ◽  
Low Fat ◽  
Breeding Values ◽  
Angus Cattle ◽  
The Difference ◽  
Supplementary Feed

The productivity of 500 Angus cows, divergently selected for either rib fat or residual feed intake (RFI) based on BREEDPLAN estimated breeding values (EBVs) and managed under two levels of nutrition (stocking rates), was evaluated. The study examined the effects of genetic line, nutrition and weaning history on profiles for weight, rib fat depth, fatness (rib fat depth adjusted for weight) and supplementary feed requirements from just before the first joining as heifers through to the weaning of their third calf. Cows gained both weight and fat as they grew older. Observed fluctuations in weight and rib fat depth, within each year, were associated with pasture availability and physiological demands. Cows that did not wean a calf in a given year became heavier and fatter than cows that did; and they remained so when they calved the following year. High-fat and High-RFI were always fatter and lighter than Low-fat and Low-RFI cows, respectively. The difference in rib fat and fatness between High- and Low-RFI lines (P < 0.001) was similar to, although slightly greater than, the difference between High- and Low-fat lines (P = 0.048) reflecting differences in rib fat EBVs between High-RFI (3.2 ± 1.47) and Low-RFI (–0.7 ± 1.3) compared with High-fat (1.1 ± 0.78) and Low-fat (–1.4 ± 0.67). Cows on High-Nutrition were heavier and fatter than those on Low-Nutrition (P < 0.001) but there were no significant interactions between genetic line and nutrition (P > 0.05). Supplementary feeding threshold was reached earlier by Low-fat and Low-RFI cows than their counterparts. Calculations based on the data in the present paper estimate that if cows lose condition at a rapid rate (1 condition score/month), then a cow with an extra 1 mm rib fat EBV would take 7.5 days longer to reach the same supplementary feeding threshold. Fat EBVs can, therefore, be a useful tool in assisting beef producers to match genotype to their production system.

Divergent breeding values for fatness or residual feed intake in Angus cattle. 6. Dam-line impacts on steer carcass compliance

2018 ◽  
Vol 58 (1) ◽  
pp. 94
Author(s):  
M. P. B. Deland ◽  
J. M. Accioly ◽  
K. J. Copping ◽  
J. F. Graham ◽  
S. J. Lee ◽  
...  
Keyword(s):  
Feed Intake ◽  
South Australia ◽  
Residual Feed Intake ◽  
Carcass Weight ◽  
Research Centre ◽  
High Fat ◽  
The South ◽  
Low Fat ◽  
Breeding Values ◽  
Estimated Breeding Values

The present study determined the impact of maternal genetics for estimated breeding values for rib fat (High-Fat, Low-Fat) or residual feed intake (RFI; High-RFI, Low-RFI) on the carcass compliance of Angus steer progeny when reared pre-weaning under High or Low-Nutrition and post-weaning under various finishing system (grazing versus short-term feedlot). The dams were joined to sires of similar genetic background (close to average estimated breeding values) and sires were rotated among all dam genotypes, with herds located at either Struan Research Centre, near Naracoorte in the south-east of South Australia, or Vasse Research Station, in the south-west of Western Australia. The breeding herd was part of the Beef CRC maternal productivity project and cows were managed under either High or Low-Nutrition, achieved by adjustments to stocking rate in rotational grazing systems and supplementary feeding, so as to maintain ~20% difference in cow liveweight. The steer progeny were weaned at ~7 months of age, with individuals from both pre-weaning nutritional treatments being treated the same from then on at each site. Steers from Struan Research Centre in South Australia born in 2008 and 2009 were sold and grown out on pasture on a local commercial property. Steer calves born in 2010 at Vasse remained on the station where they were backgrounded on hay, followed by a short period (111 days) total mixed ration containing 40% grain. In the first year, steers from Struan (n = 58) were slaughtered together at ~2 years of age, and in the second year (n = 85), consigned to six slaughter groups as their ultrasound-scanned subcutaneous P8 (rump) fat reached 7 mm and their liveweight exceeded 550 kg. Steers from Vasse (n = 101) were slaughtered at ~12 months of age, all on the same day. High-Fat-line dams produced steers with carcasses with greater P8 fat than did Low-Fat-line dams at both sites. At Struan, when the 2008-born steers were slaughtered together, more steers from Low-Fat dams failed to meet minimum fat specifications, than steers from High-Fat dams (28% vs 9% respectively). The steers born in 2009 at Struan all met processor fat specifications but steers from the Low-Fat dams took longer to reach the fat threshold, and so had greater carcass weight, but attracted more price penalties because of increased dentition. All steers from Vasse met minimum requirements for fat, with none penalised for dentition. Vasse steers from High- or Low-RFI dams performed in a manner similar to that from High- and Low-Fat dams, respectively, in that the High-RFI group produced fatter carcasses than did the Low-RFI group. Steers reared under low pre-weaning nutrition weighed less at weaning than did those on High-Nutrition, but had higher weight gains after weaning, although insufficient to result in the same carcass weight. The results showed that commercial cattle producers need to be aware of the balance and trade-off among fat breeding value, effect of pre-weaning nutrition and post-weaning growth required to ensure their cattle meet market specifications and to avoid price penalties.

Selection for residual feed intake affects appetite and body composition rather than energetic efficiency

2018 ◽  
Vol 58 (1) ◽  
pp. 175 ◽  
Author(s):  
D. S. Lines ◽  
W. S. Pitchford ◽  
C. D. K. Bottema ◽  
R. M. Herd ◽  
V. H. Oddy
Keyword(s):  
Body Composition ◽  
Heat Production ◽  
Feed Intake ◽  
Nitrogen Balance ◽  
Protein Metabolism ◽  
Energy Use ◽  
Residual Feed Intake ◽  
Daily Weight Gain ◽  
Energetic Efficiency ◽  
Selection For

Residual feed intake (RFI) is the difference between an animal’s actual feed intake and that which would be expected based on production. This experiment was to test the hypothesis that part of the variation in RFI may be due to differences in energetic efficiency through changes in heat production, these being in part due to differences in protein metabolism. Following three generations of divergent selection for RFI, eight High and eight Low-RFI heifers were fed at both 105% and 180% of predicted maintenance feed requirements. Between-RFI line and feeding-level differences were assessed for energy intake, protein metabolism, heat production, body composition, energy and nitrogen balance and digestibility. The RFI lines did not differ in protein metabolism or heat production. The High-RFI heifers deposited 51% and 56% more subcutaneous fat at the P8 rump and 12/13th rib sites, respectively, with no difference in eye muscle area gain or average daily weight gain. The greater fat deposition of High-RFI heifers was due to a larger ad libitum feed consumption compared with the Low-RFI heifers. Energy and nitrogen balance did not differ between the RFI lines. The energy transactions indicated no difference in the efficiency of energy use on 105% maintenance, although when fed 180% of maintenance the differences in feed intake suggest variation in appetite as the mechanism contributing to RFI. All of the extra energy consumed by High-RFI heifers above maintenance and deposition of protein was associated with additional energy retained as fat. This study suggests that selection for RFI may not lead to improved efficiency of energy use.

Relationship between residual feed intake classification as a heifer and lifetime productivity of beef cattle

2019 ◽  
Vol 99 (1) ◽  
pp. 191-201 ◽  
Author(s):  
C. Callum ◽  
K.H. Ominski ◽  
G. Crow ◽  
F. Zvomuya ◽  
J.A. Basarab
Keyword(s):  
Birth Weight ◽  
Pregnancy Rate ◽  
Feed Intake ◽  
Residual Feed Intake ◽  
Production Traits ◽  
Weaning Weight ◽  
Age At First Calving ◽  
Event Frequency ◽  
Productivity Measure ◽  
Selection For

The effect of residual feed intake adjusted for backfat thickness (RFIfat) on heifer pregnancy rate and subsequent lifetime productivity was examined in 867 beef females that were ranked as low, medium, or high RFIfat. Age at first calving, weaning weight of first calf, and most probable producing ability for birth weight (MPPAbw) and weaning weight (MPPAww) were calculated to assess first parity heifer productivity. The effect of heifer RFI adjusted for backfat (RFIfat; n = 532) on subsequent lifetime cow productivity (n = 415) was calculated based on kg of calf weaned per cow bred per year. A total lifetime productivity measure (n = 218) were also calculated as total calf weaning weight (kg) output per cow culled. RFI rank had no significant effect on pregnancy rate, when adjusted for season and site differences (P = 0.33). No significant correlations (P < 0.05) were observed between MPPAww and RFI, RFIfat, RFI adjusted for backfat and feeding event frequency (RFIfat & activity), or age at first calving. A negative trend (P < 0.10) between RFI, RFIfat, and MPPAbw calculated from first parity pregnancy rate and production traits was no longer apparent when adjusted for RFIfat & activity. These results suggest that selection for low RFI replacement heifers has no impact on their first parity pregnancy rate and productivity or on subsequent cow productivity.

Genetic parameters and breed differences for feed efficiency, growth, and body composition traits of young beef bulls

2004 ◽  
Vol 84 (2) ◽  
pp. 177-185 ◽  
Author(s):  
F. S. Schenkel ◽  
S. P. Miller ◽  
J. W. Wilton
Keyword(s):  
Body Composition ◽  
Genetic Correlation ◽  
Feed Intake ◽  
Feed Efficiency ◽  
Fixed Effects ◽  
Residual Feed Intake ◽  
Backfat Thickness ◽  
Daily Weight Gain ◽  
Feed Conversion ◽  
Beef Bulls

Genetic associations between feed efficiency, growth, and live ultrasound measured body composition traits were studied in purebred beef bulls of six breeds in Ontario bull test stations from 1991 to 2000. Feed traits included average daily feed intake (FI), feed conversion ratio (FCR), and residual feed intake [feed intake adjusted for production alone (RFIp) or production and backfat thickness (RFIb)]. Growth traits were average daily weight gain (ADG), mid-test metabolic weight (MW), hip height (HH), and scrotal circumference (SC). Body composition traits included ultrasound backfat thickness (BF), longissimus muscle area (LMA), and predicted percentage of intramuscular fat (IFAT). Bulls were measured every 28 d for weight and individual feed intake, and at the end of test for ultrasound body composition traits. Number of records per trait ranged from 2284 (FI) to 13 319 (ADG). Fixed effects of test group, breed and end of test age (within breed), and random effects of animal and herd of origin were modeled using REML bivariate analyses for all traits. Heritability estimates were moderate for all traits (0.30 to 0.55), except for IFAT (0.14). The genetic correlation between RFIp and RFIb was high (0.99) within breeds, but breeds ranked differently with respect to RFIp and RFIb. Genetic correlations of RFIb with ADG and backfat thickness were essentially zero, which indicate that selection on residual feed intake could be implemented to reduce feed intake and improve feed conversion without compromising growth or changing levels of subcutaneous fat. Key words: Central test, genetic correlation, heritability, residual feed intake

The effect of selection for residual feed intake on general behavioral activity and the occurrence of lesions in Yorkshire gilts1

2011 ◽  
Vol 89 (1) ◽  
pp. 258-266 ◽  
Author(s):  
L. J. Sadler ◽  
A. K. Johnson ◽  
S. M. Lonergan ◽  
D. Nettleton ◽  
J. C. M. Dekkers
Keyword(s):  
Feed Intake ◽  
Residual Feed Intake ◽  
Behavioral Activity ◽  
Selection For

230 Effect of divergent selection for residual feed intake on whole body protein turnover in growing gilts fed either adequate or lysine deficient diets

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 ◽  
...  
Keyword(s):  
Feed Intake ◽  
Protein Turnover ◽  
Residual Feed Intake ◽  
Divergent Selection ◽  
Whole Body ◽  
Body Protein ◽  
Selection For
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