Preweaning Weights in Lines of Pigs Selected for Rate of Gain and Thickness of Backfat

Vangen, O.

doi:10.1080/00015127409434192

Cited by 9 publications

(9 citation statements)

References 26 publications

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“…Second parity sows had litters that were 7.37 +-.71 kg heavier than those of gilts when adjusted for number of pigs in the litter. This difference was similar to that reported by Vangen (1974) and Swiger and Irwin (1977).…”

Section: Regression Coefficients the Partial Linearsupporting

confidence: 75%

“…Vangen (1974) studied litters from Norwegian Landrace females and estimated the first and second degree polynomials. The linear coefficients were similar to those obtained in the present study; however, the quadratic coefficients were Since there was less than a .5% reduction in the r 2 when the model was reduced from a linear and quadratic to a linear model for all data sets, it would appear that the linear partial regression coefficient would give a practical adjustment for 21-day litter weight for number of pigs at 21 days.…”

Section: Regression Coefficients the Partial Linearmentioning

confidence: 99%

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Adjustment of 21-Day Litter Weight for Number of Pigs Nursed for Purebred and Crossbred Dams

Wilson

Johnson

1980

Journal of Animal Science

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SummaryLitter data from two crossbreeding experiments were used to estimate coefficients for regressing 21-day litter weight on litter size at 21-days. Exp. 1 involved 1,003 purebred and FI gilts of Hampshire, Duroc and Yorkshire breeding and 206 second parity sows of Duroc, Hampshire and Yorkshire breeding; Exp. 2 involved 388 F 1 gilts and sows of Duroc, Yorkshire, Landrace and Spot breeding. The linear and quadratic regression coefficients from the gilt data in Exp. 1 were 5.64 + .29 kg/pig and -.10 + .02 kg/(pig) 2, respectively. For Exp. 2, the regression coefficients were 5.98 + .71 kg/pig and -.14 -+ .05 kg/(pig) 2. In both data sets, there was less than a .5% reduction in r 2 when the model was reduced from a linear and quadratic to a linear equation. The linear regression coefficients were 4.28 -+ .07 kg/pig and 3.91 -+ .14 kg/pig in Exp. 1 and 2, respectively. The linear and quadratic regression coefficients from sow data in Exp. 1 were 6.28 +-.55 kg/pig and -.14 -+ .04 kg/(pig) 2. When the model was reduced to a linear model, there was a significant interaction between breed of dam and the linear regression coefficient. These regression coefficients were 4.74 +-.25 kg/pig for Duroc, 4.73 + .26 kg/pig for Hampshire and 3.55 -+ .30 kg/pig for Yorkshire. Breed of dam differences for gilt 21-day litter weight adjusted to constant litter size were significant in Exp. 1. Duroc dam litters weighed less than litters of Hampshire, Yorkshire and the F 1 crosses. In Exp. 2, breed of dam differences were not significant for F 1 crossbred females of Duroc, Yorkshire, Landrace and Spot breeding, and I Journal Article 3692 of the Agr. Exp. Sta., Oklahoma State Univ., Stiilwater. Research was carried out in cooperation with USDA, SEA, Southern Region.

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Section: Regression Coefficients the Partial Linearsupporting

confidence: 75%

Section: Regression Coefficients the Partial Linearmentioning

confidence: 99%

Adjustment of 21-Day Litter Weight for Number of Pigs Nursed for Purebred and Crossbred Dams

Wilson

Johnson

1980

Journal of Animal Science

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“…However, the regressions on cumulative selection differential for the index were not significant. Vangen (1974) reported correlated responses (P > .05) that were positive for litter weight at birth but negative for litter weight at 42 d to index selection for rate of lean growth. DeNise et al (1983) found that selection for weight of lean cuts resulted in negative correlated responses for litter weights at birth and 21 d at first and second parity.…”

Section: Resultsmentioning

confidence: 99%

“…Hetzer and Miller (1970, 1972, 1973 and Berruecos et al (1970) have reported correlated responses to selection for low BF in swine, and correlated responses to selection for growth rate have been evaluated by Rahnefeld (1973), Garnett and Rahnefeld (1976) and Rahnefeld et al (1983). Correlated responses to index selection for rate of lean growth have been reported also (Vangen, 1974(Vangen, , 1980aFredeen and Mikami, 1986a,b,c), but precision of these estimates is generally low. The objective of this study was to estimate correlated responses in carcass and reproductive traits to five generations of index selection for increased postweaning ADG and decreased BF.…”

Section: Introductionmentioning

confidence: 99%

Correlated Responses of Carcass and Reproductive Traits to Selection for Rate of Lean Growth in Swine

Cleveland

Johnson

Cunningham

1988

Journal of Animal Science

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Mass selection for an index of increased postweaning average daily gain and decreased backfat thickness was practiced for five generations. Litter size and weight for 221 gilt litters, birth weight and nipple number for 2,242 piglets and weaning weight at 42 d of age for 2,111 pigs were recorded. Carcass measurements were taken on 331 pigs. Differences between means of the lines (select control) were regressed on cumulative selection differential of the index. These regression coefficients were negative (P > .10) for total number born, number born alive, number weaned per litter, nipple number and carcass backfat thickness. Coefficients were positive (P > .10) for individual pig and litter weights at birth and weaning and for the carcass traits of length, longissimus muscle area and percentage of ham and loin. Absolute values of realized genetic corrdations of index with traits evaluated were all .35 or less except the correlation with carcass backfat, which was -.84. None of these was significant; therefore, index selection for lean growth should have little effect on litter size and weight but may have a beneficial effect on carcass backfat.

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“…4), but only the response for litter weight at 42 d was significantly different from zero (Table 2). Vangen (1974) reported that correlated responses to index selection for rate of lean growth were positive (P > 0.05) for litter weight at birth but negative for litter weight at 42 d. DeNise et al (1983) found that selection for weight of lean cuts resulted in negative correlated responses for litter weights at birth and 21 d in first and second parity, but responses were significant only for second parity sows. Fredeen and Mikami (1986) observed a significant negative phenotypic trend over years for litter weight at birth in a Lacombe line.…”

Section: Litter Weight Traitsmentioning

confidence: 99%

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

Chen¹,

Baas²,

Dekkers³

et al. 2001

Can. J. Anim. Sci.

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[205][206][207][208][209][210][211][212][213][214]. 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 number alive 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. LGR ont été sélectionnés pour produire la génération suivante. L'intervalle entre les générations était de 13 mois et le différentiel de sélection moyen par génération s'établissait à 1,1 unité d'écart-type phénotypique. Parallèlement, on a élevé une lignée témoin de contemporains en sélectionnant au hasard 5 verrats et 15 truies nullipares. Les deux lignées ont permis de recueillir des données sur 1 057 porcs venant de l'accouplement de 58 verrats avec 133 truies. On a estimé les effets de la sélection en appliquant la méthode des moindres carrés (LS) et un modèle animal reposant sur la méthode du maximum de vraisemblance restreint sans dérivée pour les caractères multiples aux écarts entre la lignée sélectionnée et la lignée témoin. La réaction à la sélection estimative était de 9,4 ± 0,95 g par jour par génération selon la LS et de 9,8 ± 0,51 g par jour pour le modèle animal. La variation des caractères de la portée qui présentent une corrélation avec la réaction de la sélection a fait l'objet d'une analyse de régression pour la génération. Les coefficients de régression était nég...

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Preweaning Weights in Lines of Pigs Selected for Rate of Gain and Thickness of Backfat

Cited by 9 publications

References 26 publications

Adjustment of 21-Day Litter Weight for Number of Pigs Nursed for Purebred and Crossbred Dams

Adjustment of 21-Day Litter Weight for Number of Pigs Nursed for Purebred and Crossbred Dams

Correlated Responses of Carcass and Reproductive Traits to Selection for Rate of Lean Growth in Swine

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

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