Response to Selection for Feed Efficiency in Individually Fed Yorkshire Boars

Jungst, Steve B.; Christian, L. L.; Kuhlers, D. L.

doi:10.2527/jas1981.532323x

Cited by 37 publications

(19 citation statements)

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“…The heritability estimate for the feed conversion ratio was low (0.10) and in agreement with estimates of 0.06 for Rambouillet and 0.18 for Romnelet ram lambs reported by Vesely et al (1970). Estimates for other species have been low to moderate (0.12 for goats, Khan and Singh, 1995;0.16 and 0.26 for beef cattle, Fan et al, 1995 andBishop et al, 1991, respectively;0.12 for swine, Jungst et al, 1981;and, 0.27 for mice, Sutherland et al, 1970).…”

Section: Resultssupporting

confidence: 61%

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Estimates of genetic parameters and selection strategies to improve the economic efficiency of postweaning growth in lambs1

Snowder

Vleck

2003

Journal of Animal Science

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ABSTRACT:The objectives of this study were to estimate (co)variance components for growth and feed efficiency measures, and to compare selection strategies to improve economic efficiency of gain. Variance components for pre-and postweaning growth, body weight, and measures of feed efficiency were estimated from data collected on 1,047 Targhee lambs over 7 yr. Approximately 21 d after weaning, lambs were group-fed for 4 wk, with ad libitum access to a diet of 37% whole barley grain and 63% pelleted alfalfa hay. Lambs were then individually fed for 6 wk. Lambs were then returned to group feeding for another 4-wk period. The mean feed conversion ratio (gain/intake) for the individual feeding period was 0.11. Mean postweaning ADG for the total 14-wk feeding period was 0.26 kg. (Co)variance components were estimated from single-and two-trait animal models using REML. The selection strategies compared included direct selection, index selection, and restricted index selection. Estimates of (co)variances derived from single-and two-trait models were similar,

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Section: Resultssupporting

confidence: 61%

“…Lower estimates for daily feed intake have been reported for lambs (0.25, Leymaster et al, 2002) and swine (0.22, Jungst et al, 1981). Heritability estimates for feed intake in beef cattle have been high (0.40, Scholtz et al, 1998;and 0.39, Arthur et al, 2001a).…”

Section: Resultsmentioning

confidence: 97%

Estimates of genetic parameters and selection strategies to improve the economic efficiency of postweaning growth in lambs1

Snowder

Vleck

2003

Journal of Animal Science

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“…However, Bereskin (1986) reported a considerably lower heritability (0.10) for ADG of group fed Duroc and Yorkshire gilts. The reasons for differences in estimates of heritability might be due to feeding method (Jungst et al, 1981). Higher values of heritability for ADG can be expected when pigs are individually fed (Robison and Berruecos, 1973).…”

Section: Discussionmentioning

confidence: 98%

Genetic parameters for measures of residual feed intake and growth traits in seven generations of Duroc pigs

et al. 2009

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“…The results of direct selection in swine for food conversion ratio are discouraging (Dickerson and Grimes, 1947;Jungst et al, 1981), even though selection for improved food conversion ratio in chickens reduced the food to gain ratio (Pym and Nicholls, 1979) and improved the carcass lean to fat ratio (Pym and Solvyns, 1979). In swine, index selection for increased growth rate and decreased backfat has been effective (Fredeen et al, 1976;Ollivier, 1977;Vangen, 1979;Cleveland et al, 1982).…”

Section: Discussionmentioning

confidence: 99%

“…The poor response to direct selection for food conversion ratio (Jungst et al, 1981) and the higher improvements obtained from index selection for growth rate and backfat raises Clearly, improved lean tissue food conversion should be a breeding objective. The present results, however, lead us to question the value of placing food conversion ratio in the selection index.…”

Section: Discussionmentioning

confidence: 99%

Index Selection and Feed Intake Restriction in Swine. II. Effect on Energy Utilization

Cleveland

Johnson

Mandigo

et al. 1983

Journal of Animal Science

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SummaryFifty-three index select and control line barrows were randomly assigned to three feeding levels at 83 d of age. They were slaughtered at approximately 188 d of age to determine the effects of index selection (for increased average daily gain and decreased backfat) and level of feed intake on energy utilization. During the trial, the feed intake levels were twice daily to appetite (AP), once daily feeding of 91% of appetite (AP91) or once daily feeding of 82% of appetite (AP82) intake. The metabolizable energy intake required per kilogram of edible lean deposited (Mcal/kg) was reduced (P<.05) by restricting intake and was lower (P<.01) for index than for control barrows [index: 25.6 (AP), 23.3 (AP91) and 25.3 (AP82) vs control: 31.1 (AP), 27.5 (AP91) and 28.1 (AP82)]. However, intake restriction and index selection increased (P<.05) the energy lost per unit of retained energy (index: 1.33, 1.45 and 1.53 vs control: 1.24, 1.29 and 1.34). The index line had a higher (P<.05) maintenance requirement than the control line when expressed'unit of weight (kg'TS) -1" day -I, but the difference was less when expressed'unit of lean (kg'S3)-l'day -I. The energy cost of protein deposition varied from 9.02 to 11.25 kcal/g, while the energy cost of fat deposition ranged from 12.73 to 12.86 kcal/g. Variation among animals in metabolizable energy intake was explained by variation in lean mass maintained and the quantity of prOtein and fat deposited.

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Response to Selection for Feed Efficiency in Individually Fed Yorkshire Boars

Cited by 37 publications

References 0 publications

Estimates of genetic parameters and selection strategies to improve the economic efficiency of postweaning growth in lambs1

Estimates of genetic parameters and selection strategies to improve the economic efficiency of postweaning growth in lambs1

Genetic parameters for measures of residual feed intake and growth traits in seven generations of Duroc pigs

Index Selection and Feed Intake Restriction in Swine. II. Effect on Energy Utilization

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