BREEDING FOR FEED EFFICIENCY: SWINE AND DAIRY CATTLE

1984 ◽  
Vol 64 (3) ◽  
pp. 505-512 ◽  
Author(s):  
B. W. KENNEDY
Keyword(s):  
Growth Rate ◽  
Dairy Cattle ◽  
Feed Efficiency ◽  
Large Scale ◽  
Experimental Studies ◽  
Direct Selection ◽  
Correlated Response ◽  
Selection For ◽  
Potential Improvement ◽  
Current Selection

Feed efficiency in dairy cattle is moderately heritable and selection for its improvement theoretically would be effective. Despite this, direct selection for feed efficiency is not practiced in dairy cattle. Growth of milk recording programs which monitor feeding information has made selection for feed efficiency, or at least efficiency of concentrate conversion, possible on a large scale. However, it has been estimated that correlated response to direct selection for increased milk yield probably results in 70–95% of the potential improvement in feed efficiency that could be achieved through direct selection for feed efficiency. Current selection practices for increased body size may be detrimental to feed efficiency. In swine also, little direct selection for improved feed efficiency is practiced. Experimental studies for selection for feed efficiency have been less successful than expected. Correlated response from selection for an index that combines growth rate and backfat seems to be as effective in improving feed efficiency as direct selection. Development of automated feeding devices which allow measurement of individual feed intake under group penning will facilitate monitoring of and selection for improved feed efficiency. Key words: Selection, feed efficiency, swine, dairy cattle

MASS SELECTION FOR POSTWEANING GROWTH IN SWINE. III. CORRELATED RESPONSE IN WEANING WEIGHT AND FEED EFFICIENCY TO RECURRENT SELECTION FOR POSTWEANING AVERAGE DAILY GAIN IN SWINE

1973 ◽  
Vol 53 (2) ◽  
pp. 173-178
Author(s):  
G. W. RAHNEFELD
Keyword(s):  
Genetic Correlation ◽  
Feed Efficiency ◽  
Average Daily Gain ◽  
Direct Selection ◽  
Correlated Response ◽  
Mass Selection ◽  
Total Response ◽  
Weaning Weight ◽  
Selection For ◽  
Daily Gain

Correlated response in weaning weight and feed efficiency were estimated for a genetically variable population of swine selected during nine generations for postweaning average daily gain. Total response in weaning weight to direct selection for gain was 0.03 kg per generation. This was 3.1% of the predicted response. The estimate of genetic correlation between postweaning average daily gain and weaning weight was found high and positive (> 1). Total response in feed efficiency to direct selection for gain was −0.58 kg per generation. This was 10% of the predicted response. The estimate of genetic correlation between postweaning gain and feed efficiency was −0.35.

Selection for components of efficient lean growth rate in pigs 2. Selection pressure applied and direct responses in a Landrace herd

1994 ◽  
Vol 59 (2) ◽  
pp. 263-269 ◽  
Author(s):  
N. D. Cameron ◽  
M. K. Curran
Keyword(s):  
Growth Rate ◽  
Genetic Correlations ◽  
Correlated Response ◽  
Selection Line ◽  
Control Line ◽  
Direct Response ◽  
Lean Growth ◽  
Ad Libitum ◽  
Selection For ◽  
Ad Libitum Feeding

AbstractResponses to divergent selection for lean growth rate with ad-libitum feeding (LGA), for lean food conversion (LFC) and for daily food intake (DFI) in Landrace pigs were studied. Selection was practised for four generations with a generation interval ofl year. A total of 2642 pigs were performance tested in the high, low and control lines, with an average of 37 boars and 39 gilts performance tested per selection line in each generation. The average within-line inbreeding coefficient at generation four was equal to 0·04. There was one control line for the DFI and LFC selection groups and another control line for the LGA selection group. Animals were performance tested in individual pens with mean starting and finishing weights of 30 kg and 85 kg respectively with ad-libitum feeding. The selection criteria had phenotypic s.d. of 32, 29 and 274 units, for LGA, LFC and DFI, respectively, and results are presented in phenotypic s.d.Cumulative selection differentials (CSD) were 5·1, 4·5 and 5·5 phenotypic s.d. for LGA, LFC and DFI, respectively. Direct responses to selection were 1·4,1·1 and 0·9 (s.e. 0·20) for LGA, LFC and DFI. In each of the three selection groups, the CSD and direct responses to selection were symmetric about the control lines. The correlated response in LFC (1·1, s.e. 0·19) with selection on LGA was equal to the direct response in LFC. In contrast, the direct response in LGA was greater than the correlated response (0·7, s.e. 0·18) with selection on LFC. There was a negative correlated response in DFI (-0·6, s.e. 0·18) with selection on LFC, but the response with selection on LGA was not significant (0·2, s.e. 0·16).Heritabilities for LGA, LFC and DFI ivere 0·25, 0·25 and 0·18 (s.e. 0·03), when estimated by residual maximum likelihood, with common environmental effects of 0·12 (s.e. 0·02). Genetic correlations for LFC with LGA and DFI were respectively positive (0·87, s.e. 0·02) and negative (-0·36, s.e. 0·09), while the genetic correlation between DFI and LGA was not statistically different from zero, 0·13 (s.e. 0·10). Selection on components of efficient lean growth has identified LGA as an effective selection objective for improving both LGA and LFC, without a reduction in DFI.

Selection for lean growth rate and correlated responses in litter traits in a synthetic line of Yorkshire-Meishan pigs

2001 ◽  
Vol 81 (2) ◽  
pp. 205-214 ◽  
Author(s):  
P. Chen ◽  
T. J. Baas ◽  
J. C. M. Dekkers ◽  
L. L. Christian
Keyword(s):  
Growth Rate ◽  
Regression Coefficients ◽  
Correlated Response ◽  
Selection Line ◽  
Control Line ◽  
Correlated Responses ◽  
Lean Growth ◽  
Litter Traits ◽  
Selection For ◽  
Synthetic Line

Selection for lean growth rate (LGR) was conducted for four generations in a synthetic line of Yorkshire-Meishan pigs to study the effectiveness of selection for LGR and correlated responses in litter traits. Lean growth rate was estimated from ultrasound measurements of 10th-rib backfat thickness and longissimus muscle area. In the selection line, 7 boars and 20 gilts with the highest LGR were selected to produce the next generation. The generation interval was 13 mo and the average selection differential per generation was 1.1 phenotypic standard deviation units. A contemporaneous control line was maintained by randomly selecting 5 boars and 15 gilts. Data from a total of 1057 pigs sired by 58 boars and out of 133 sows were available from the two lines. Selection responses were estimated from deviations of the selection line from the control line using least squares (LS) and by multiple trait derivative-free restricted maximum likelihood analysis using an animal model (AM). The estimate of response to selection per generation using LS was 9.4 ± 0.95 g d–1 for LGR. The corresponding estimate from the AM was 9.8 ± 0.51 g d–1. Correlated responses in litter traits were regressed on generation. For the LS method, regression coefficients were negative but not significant (P > 0.05) for total number born, number born alive, and number at 21 d and at 42 d. Significant, positive correlated responses occurred in 42-d litter weight and 21-d piglet weight (P < 0.05). For the AM method, the regression coefficients were also negative, but were not significant (P > 0.05) for numberalive at birth, at 21 d, and at 42 d. A significant positive correlated response occurred only for 42-d litter weight (P < 0.05). Although results are based on a population of limited size, it can be concluded that selection for LGR in a synthetic line is effective and should have little effect on litter traits. Key words: Pigs, selection, lean growth rate, correlated response

Selection on ram 18-month weight to improve lamb growth rate

1983 ◽  
Vol 36 (2) ◽  
pp. 159-164
Author(s):  
D. Croston ◽  
J. L. Read ◽  
D. W. Jones ◽  
D. E. Steane ◽  
C. Smith
Keyword(s):  
Growth Rate ◽  
Live Weight ◽  
Indirect Selection ◽  
Direct Selection ◽  
Selection For ◽  
The Relationship ◽  
Lamb Growth

ABSTRACTThirteen pairs of Suffolk rams were selected on high and low 18-month adjusted live weight from six farms over 2 years, to establish the relationship between 18-month weight and early lamb growth. Progeny were first produced in recorded crossbred flocks (618 lambs) and then in an experimental flock of crossbred ewes (1083 lambs). Different results were obtained from the recorded and experimental flocks. The regressions of lamb 12- to 13-week weight on ram 18-month weight (within farm deviation) were 0·053 ± 0·022 kg and –0·004 ± 0·020 kg, respectively. These regressions for indirect selection correspond to ‘effective’ heritabilities for direct selection for lamb growth of 0·18 ± 0·07 and 0·02 ± 0·06 respectively. Improvement of early Iamb growth is discussed and it is concluded that selection for 18-month weight is unlikely to be a useful method.

scholarly journals Results of selection for breast muscle percentage and feed conversion ratio in Pekin ducks

2011 ◽  
Vol 27 (3) ◽  
pp. 769-776 ◽  
Author(s):  
H. Pingel
Keyword(s):  
Feed Efficiency ◽  
Conversion Ratio ◽  
Feed Conversion Ratio ◽  
Breast Muscle ◽  
Feed Consumption ◽  
Direct Selection ◽  
Meat Production ◽  
Feed Conversion ◽  
Nitrogen And Phosphorus ◽  
Selection For

Increasing breast muscle percentage by selection for breast layer thickness (muscle and skin) of living ducks by needle probe improves carcass quality as could be demonstrated by experiments and by applied breeding programs. In addition direct selection for individual feed conversion ratio can increase the efficiency of duck meat production. Divergent selection for feed conversion ratio from the age of 4 - 7 weeks over 11 generations has differentiated the feed efficiency by about 25 %. Causes for the reduction in feed conversion ratio are lower fat content of carcass, lower locomotor activity, higher enzymatic activity (alkaline phosphatase and creatinkinase in blood plasma) and better feed protein utilization. Because of lower feed consumption in the line selected for lower feed conversion ratio the emission of nitrogen and phosphorus via manure was reduced by about 39 and 26 %, respectively. That means, selection for better feed efficiency is not only an important economical but also an important ecological factor.

The use of station and field tests for the improvement of milking performance in dairy cattle. II. Milking rate and time as indicators of a cow's milking ability

1968 ◽  
Vol 10 (2) ◽  
pp. 201-207 ◽  
Author(s):  
C. J. M. Hinks ◽  
E. O. Nielsen ◽  
A. Neimann-Sørensen
Keyword(s):  
Dairy Cattle ◽  
Average Rate ◽  
Field Tests ◽  
Direct Selection ◽  
Productive Performance ◽  
Testing Programme ◽  
Selection For

An investigation of milking ability in three dairy breeds has shown that selection for superior productive performance would contribute little to the improvement of milking time. The heritability of both average rate of flow and milking time was reasonably high in all three breeds, however, and direct selection should result in effective improvements.The problem of slow milking was more acute in the Danish Red breed, in which almost one cow in ten needed more than six minutes to milk out, than in the Black Pied or Danish Jersey breeds.A comparison of the average rate of flow and milking time as criteria of selection for milking ability indicated that both measures were equally effective in the Black Pied and Jersey breeds, but that rate of flow was considerably more (40%) effective than milking time in the Danish Reds. This was largely because the heritability of milking time in this breed was only one-third that of milking rate.It was concluded that the average rate of flow was to be preferred to milking time as a criterion of selection for milking ability in the Danish station testing programme.

scholarly journals Heritability of Teat Condition in Italian Holstein Friesian and Its Relationship with Milk Production and Somatic Cell Score

Animals ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2271
Author(s):  
Francesco Tiezzi ◽  
Antonio Marco Maisano ◽  
Stefania Chessa ◽  
Mario Luini ◽  
Stefano Biffani
Keyword(s):  
Dairy Cattle ◽  
Somatic Cell ◽  
Milk Yield ◽  
Genetic Factors ◽  
Genetic Correlations ◽  
Somatic Cell Score ◽  
Cattle Industry ◽  
Holstein Friesian ◽  
Selection For ◽  
Current Selection

In spite of the impressive advancements observed on both management and genetic factors, udder health still represents one of most demanding objectives to be attained in the dairy cattle industry. Udder morphology and especially teat condition might represent the first physical barrier to pathogens’ access. The objectives of this study were to investigate the genetic component of teat condition and to elucidate its relationship with both milk yield and somatic cell scores in dairy cattle. Moreover, the effect of selection for both milk yield and somatic cell scores on teat condition was also investigated. A multivariate analysis was conducted on 10,776 teat score records and 30,160 production records from 2469 Italian Holstein cows. Three teat scoring traits were defined and included in the analysis. Heritability estimates for the teat score traits were moderate to low, ranging from 0.084 to 0.238. When teat score was based on a four-classes ordinal scoring, its genetic correlation with milk yields and somatic cell score were 0.862 and 0.439, respectively. The scale used to classify teat-end score has an impact on the magnitude of the estimates. Genetic correlations suggest that selection for milk yield could deteriorate teat health, unless more emphasis is given to somatic cell scores. Considering that both at national and international level, the current selection objectives are giving more emphasis to health traits, a further genetic deterioration in teat condition is not expected.

LIVE PERFORMANCE AND CARCASS CHARACTERISTICS OF BEEF BULLS IN RELATION TO SELECTION FOR YEARLING WEIGHT

1970 ◽  
Vol 50 (3) ◽  
pp. 491-497 ◽  
Author(s):  
A. H. MARTIN ◽  
H. T. FREDEEN ◽  
J. A. NEWMAN
Keyword(s):  
Growth Rate ◽  
Live Weight ◽  
Direct Selection ◽  
Control Line ◽  
Live Performance ◽  
Carcass Yield ◽  
Yield And Quality ◽  
Lean Growth ◽  
Kidney Fat ◽  
Selection For

Data over two years on a total of 149 Shorthorn bulls from a closed herd under direct selection for yearling weight were used to examine line differences in carcass yield and quality and to evaluate relationships between live performance and carcass yield and quality. No significant differences [Formula: see text] in performance or carcass data between control and selected lines were apparent in 1967. However, in 1968 bulls from the selected line were heavier at slaughter (470.5 kg vs. 441.8 kg), their carcasses contained more kidney fat (9.14 kg vs. 8.46 kg), and they had larger loin eye area but smaller weight-adjusted loin eye area. Rate of gain was superior for the selected line whether examined as live-weight, carcass weight, trimmed primal cut weight or lean weight per day of age. There were no significant differences between lines for percent fat, lean or bone in primal cuts, or for rib fat thickness, percent trimmed prime cuts, percent seam fat, muscle/bone and hind/front ratios, or for chemical composition or tenderness evaluations of the longissimus dorsi. Averaged over the two years and at the same averaged slaughter weights (418 days), selected-line bulls produced a significantly greater quantity of total carcass, of trimmed primal cuts and of total lean than did the control-line bulls; selection for yearling weight appeared to have been effective in increasing rate of lean growth. Phenotypic correlations indicated that liveweight/day of age was more highly related to variation in lean growth rate than growth rate of fat. From 20 to 60% of the variation in wholesale cut weights was associated with differences in rate of gain. Distribution of the gains was little influenced by rate of gain. Tenderness evaluations were not related to live performance.

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