scholarly journals Relationships between litter size, sex ratio and within-litter birth weight variation in a sow herd and consequences on weaning performance

2021 ◽  
Author(s):  
Titus J Zindove ◽  
Tonderai Mutibvu ◽  
Andrew C Shoniwa ◽  
Erica L Takaendesa
Keyword(s):  
Birth Weight ◽  
Sex Ratio ◽  
Litter Size ◽  
Research Unit ◽  
Weaning Weight ◽  
Male And Female ◽  
Litter Weight ◽  
Regression Procedure ◽  
Weight Variation ◽  
Selection For

Abstract Routine selection for litter size has resulted in increase in the proportion of lightweight piglets. There is a need to balance prolificacy with litter uniformity in order to maximise profit. A total of 3 465 piglets from 310 litter records obtained from 2016 until 2019 at the Pig Industry Board research unit, Arcturus, Zimbabwe, were used to determine the relationships between litter size, sex ratio and within-litter birth weight variation in the sow herd and consequences on performance at weaning. The regression procedure of SAS was used to determine the relationships between litter size, sex ratio and within-litter birth weight variation. The regression procedure was also used to determine the relationships between number born alive, within-litter birth weight variation, and sex ratio, and litter performance traits at weaning. Parity of sow, year and month of farrowing did not affect sex ratio (P > 0.05). The number born alive and number of piglets born had no relationship with sex ratio (P > 0.05). As the sex ratio increased, percent survival of piglets at weaning also increased linearly (P < 0.05). As the proportion of males in litters increased, within-litter birth weight variation and within-litter weaning weight variation increased reaching maximum as the proportion of males in litters approached 0.5 and then decreased onwards. As the proportion of males in litters approached 1, within-litter birth weight variation and within-litter weaning weight variation reached their least values. In conclusion, within-litter sex ratio does not vary with parity, year and month of farrowing. Within-litter weight variation is highest in litters with equal number of male and female piglets and lowest in unisex litters. This implies that production of unisex litters can help to reduce the variation in the weight of pigs at birth, weaning, and marketing which is one of the biggest economic challenges faced by pork producers.

scholarly journals Genetic Analysis Of Rabbit Litter Traits At Birth And Weaning

2021 ◽  
Vol 19 ◽  
pp. 64-69
Author(s):  
I. K Odubote ◽  
B. Somade
Keyword(s):  
Birth Weight ◽  
Genetic Analysis ◽  
Litter Size ◽  
Weaning Weight ◽  
Litter Weight ◽  
Phenotypic Correlations ◽  
Litter Traits ◽  
Genetic And Phenotypic Correlations ◽  
Selection For ◽  
Size At Birth

Data on 260 litters were used to provide therefore to estimate the heritability and estimates of heritability, repeatability, genetic and phenotypic correlations for litter traits at birth and at weaning. Breed, sire within breed and doe within sire effects were found to be significant, (P<0.05) for litter size at birth and at weaning and for litter weight at birth and at weaning. Heritability estimates of 0.33±0.08, 0.38±0.02, 0.03±0.02 and 0.16±0.05 were obtained for litter birth weight, litter size at birth, litter size at weaning and litter weaning weight, respectively. Repeatability estimates were found to be generally moderate to high. Genetic and phenotypic correlations were positive and significant (P<0.01). Selection for litter size at birth and litter birth weight are likely to result in improved litter size at weaning and litter weaning weight respectively.

Comparative farrowing to weaning performance in Meishan and Large White pigs and their crosses

1995 ◽  
Vol 60 (2) ◽  
pp. 269-280 ◽  
Author(s):  
G. J. Lee ◽  
C. S. Haley
Keyword(s):  
Birth Weight ◽  
Standard Deviation ◽  
Litter Size ◽  
Large White ◽  
Weaning Weight ◽  
Growth And Survival ◽  
Probability Of Survival ◽  
Litter Weight ◽  
Litter Traits ◽  
Breed Differences

AbstractGrowth and survival from birth to weaning were monitored during three generations of crossbreeding between British Large White (LW) and Chinese Meishan (MS) pigs. The design allowed comparisons between sow genotypes ranging from zero to all MS genes, which were mated toLWor MS boars, to produce progeny with proportions of 0·0 to 0·5 or 0·5 to 1·0 MS genes, respectively. Crossbreeding parameters of both maternal and direct piglet performance were estimated for the first two parities using restricted maximum likelihood (REML) methods for litter traits (litter weight at birth, litter mean and within litter standard deviation of piglet weight at birth, proportion surviving to weaning, litter size and weight at weaning and litter mean piglet weight at weaning) and for traits of the piglet (birth weight, probability of survival and weaning weight). For litter traits, the estimated contribution of the additive maternal effect to the breed differences (MS-LW) was significant for litter mean piglet birth weight (–0·46 (s.e. 0·04) kg), survival to weaning (0·15 (s.e. 0·02)), litter size at weaning (1·6 (s.e. 0·16) piglets), litter weaning weight (–11·2 (s.e. 3·8) kg) and litter mean piglet weaning weight (2·54 (s.e. 0·24) kg). Adding litter size and litter mean piglet birth weight to the model removed the additive maternal contribution to the breed differences in survival, and litter size and reduced that for litter mean piglet weaning weight. The contribution of the direct additive effect to the breed difference (MS-LW) was significant for the within litter standard deviation in birth weight (0·018 (s.e. 0·006)), survival to weaning (0·12 (s.e. 0·02)) and litter size (1·12 (s.e. 0·64)) and weight (11·6 (s.e. 4·0) kg) at weaning, but not for piglet weight at birth or weaning. Fitting litter size and litter mean birth weight had comparatively little impact on the direct additive effects. There were significant maternal heterosis effects for litter weight at birth and litter size and weight at weaning, the estimated deviation of the F1 from the midpoint of the two purebreds 3·22 (s.e. 0·55) kg, 2·20 (s.e. 0·47) piglets, and 20·1 (s.e. 3·3) kg respectively, but none for survival or piglet weights. There were direct heterosis effects for litter weight and litter mean piglet weights, the estimated deviation of the Fjfrom the mid point of the two purebreds being 1·16 (s.e. 0·41) kg and 0·14 (s.e. 0·02) kg, for survival to weaning (0·04 (s.e. 0·02)) and for litter weight (11·2 (s.e. 2·5) kg) and litter mean piglet weight (0·96 (s.e. 0·17) kg) at weaning. Fitting litter size and litter mean piglet birth weight removed or reduced both maternal and direct heterosis effects. Individual piglet analyses gave similar results to analyses of the equivalent sow trait. It was concluded that in litters born to MS cows, the lower piglet survival and lower weaning weights were related to the larger litter sizes and lower piglet birth weights. For their birth weight, however, MS piglets have a greater ability to survive and thrive. The large direct and maternal heterosis effects observed for litter and mean piglet weight at weaning werepartly associated with the heavier birth weight of the crossbred piglet.

scholarly journals The effects of breed, sire and environmental factors on the birth and weaning weight of lambs

2020 ◽  
Vol 108 (4) ◽  
pp. 70-78
Author(s):  
S. Kramarenko ◽  
◽  
A. Kramarenko ◽  
S. Lugovoy ◽  
D. Balan ◽  
...  
Keyword(s):  
Birth Weight ◽  
Environmental Factors ◽  
Litter Size ◽  
Analysis Of Variance ◽  
Significant Influence ◽  
Research Data ◽  
Weaning Weight ◽  
Factors Influencing ◽  
Size Type

The effects of breed, sire and environmental factors on the birth and weaning weight of lambs The aim of this study was to determine the effect of some important factors influencing on the birth and weaning weight variability in lambs. Data from 2603 ewes was included in the analysis, where 3961 lambs were obtained during the five years of the research. Data was tested using analysis of variance (ANOVA) with the GLM procedure of Minitab Release 13.1. Our results presented significant influence on the year of lambing, breed, ram genotype, age of a dam, type of a birth (litter size), sex of a lamb and on the birth weight and weaning weight of lambs. Keywords: birth and weaning weight of lambs; ram genotype; year of lambing; age of ewes; litter size (type of birth); sex of a lamb; the Ascanian fine-fleece breed.

scholarly journals PSXI-5 Effect of increasing feed intake during late gestation on piglet birth weight and weaning weight of low backfat thickness sows

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 387-388
Author(s):  
Yuanfei Zhou ◽  
Zuhong Liu ◽  
Jian Peng
Keyword(s):  
Birth Weight ◽  
Feed Intake ◽  
Energy Requirement ◽  
Body Weight Loss ◽  
Late Gestation ◽  
Backfat Thickness ◽  
Large White ◽  
Weaning Weight ◽  
Weight Variation ◽  
High Feed

Abstract This study investigated the effect of feed intake during late gestation on piglet birth weight and weaning weight of sows with the low backfat thickness (BF) at gestation 90 d. A total of 397 crossbred Landrance × Large White sows according to feed intakes were randomly allotted to three groups 2.8 kg/d (the energy requirement for sow maintenance), 3.6 kg/d and 4.0 kg/d from day 90 to day 110 of gestation. Sows were weighed and measured BF at 90 d and at 110 d of gestation and at weaning. Piglet performance at parturition and at weaning and wean-to-estrus of sows were recorded. Although sows had a tendency to increase BF at gestation 110 d (P = 0.09) and had more BF gain during late gestation with higher feed intake (P &lt; 0.01), there was no evidence for differences in piglet birth weight, within-litter birth weight variation and weak piglet rate, and the number of total born, born alive and stillborn. During lactation, sows fed with high feed intake in late gestation increased body weight loss (P &lt; 0.01). And no differences were observed in piglet performance at weaning and wean-to-estrus interval of sows. In conclusion, during late gestation, sows fed with feed intake more than energy requirement for maintenance had no effect on piglet birth weight or weaning weight.

Bayesian analysis of selection for greater weaning weight while maintaining birth weight in beef cattle

2009 ◽  
Vol 87 (10) ◽  
pp. 3089-3096 ◽  
Author(s):  
L. M. Melucci ◽  
A. N. Birchmeier ◽  
E. P. Cappa ◽  
R. J. C. Cantet
Keyword(s):  
Birth Weight ◽  
Beef Cattle ◽  
Bayesian Analysis ◽  
Weaning Weight ◽  
Selection For

The role of selection in the improvement of Welsh Mountain sheep

1958 ◽  
Vol 9 (6) ◽  
pp. 819 ◽  
Author(s):  
JM Doney
Keyword(s):  
Birth Weight ◽  
Maternal Environment ◽  
Weaning Weight ◽  
Phenotypic Correlations ◽  
Selection For ◽  
Heritability Estimates ◽  
Fleece Weight ◽  
Staple Length

Means and variances of several economic characters in Welsh Mountain sheep are given. The repeatabilities of, and phenotypic correlations between, these characters are generally within the range of similar estimates given for other breeds. Heritabilities, calculated from parent-offspring correlations, were : birth weight 0.39, weaning weight 0.68, 18-month weight 0.59, greasy fleece weight 0.61, and staple length 0.73. These values are in general higher than similarly derived estimates from other breeds. A method of correcting heritability estimates to remove the error due to correlation between maternal environment, and the character as measured in the dam, is described. This reduces the estimate for weaning weight to 0.48, and that for 18-month weight to 0.16, but does not change that for fleece weight. The use of such estimates in predicting the effect of selection is discussed, and it is concluded that accurate selection for the chosen economic characters will result in improvement at the present genetic stage of the breed.

Estimates of genetic parameters for pre-weaning and post-weaning growth traits of Chios lambs

1980 ◽  
Vol 30 (2) ◽  
pp. 271-276 ◽  
Author(s):  
A. P. Mavrogenis ◽  
A. Louca ◽  
O. W. Robison
Keyword(s):  
Body Weight ◽  
Birth Weight ◽  
Genetic Parameters ◽  
Growth Traits ◽  
Genetic Correlations ◽  
Heritability Estimate ◽  
Weaning Weight ◽  
Phenotypic Correlations ◽  
Selection For ◽  
Daily Gain

ABSTRACTData on 792 Chios lambs born during the 1972/73 and 1973/74 lambing seasons were used to estimate genetic and phenotypic parameters for birth weight, weaning weight, age at weaning, pre-weaning daily gain, body weight at 5, 10, 15 and 20 weeks of age, and postweaning daily gain. Body weight at 15 weeks of age had the highest heritability estimate (0·73 ± 0·17) and that of post-weaning daily gain was also high (0·56 ± 0·15). Selection for either weight at 15 weeks or post-weaning daily gain would be expected to yield a greater response than selection for pre-weaning daily gain or weaning weight. Genetic correlations among weights and/or gains were positive (approximately 0·20). Phenotypic correlations among weights and gains were generally higher than genetic correlations. However, the correlation between pre— and post-weaning daily gain was small (0·08). Likewise, post-weaning daily gain had low correlations with all weights before 10 weeks. Age at weaning had moderate negative associations with all weights but a very low positive correlation with post-weaning daily gain.

Genetic relationships between seasonal tissue levels in Scottish Blackface ewes and lamb growth traits

2005 ◽  
Vol 81 (1) ◽  
pp. 11-21 ◽  
Author(s):  
N. R. Lambe ◽  
S. Brotherstone ◽  
M. J. Young ◽  
J. Conington ◽  
G. Simm
Keyword(s):  
Weight Gain ◽  
Birth Weight ◽  
Litter Size ◽  
Growth Traits ◽  
Genetic Relationships ◽  
Genetic Correlations ◽  
Muscle Weight ◽  
Litter Weight ◽  
Weight Gains ◽  
Lamb Growth

AbstractScottish Blackface ewes (no. = 308) were scanned four times per year using X-ray computed tomography (CT scanning) (pre-mating, pre-lambing, mid lactation and weaning), from 18 months to 5 years of age, giving a maximum of 16 scanning events per ewe. Total weights of carcass fat, internal fat and carcass muscle were estimated from the CT images at each scanning event. Lambs produced by these ewes were weighed at birth, mid lactation and weaning to calculate litter growth traits: litter birth weight; litter weight gain from birth until mid lactation; and litter weight gain from birth until weaning. Genetic (rg) and phenotypic (rp) correlations were estimated between ewe CT tissue traits and litter growth traits. Correlations between ewe CT tissue traits and litter size (LS) were also estimated. Ewe CT tissue traits were either unadjusted or adjusted for total soft tissue weight (sum of weights of carcass fat, internal fat and carcass muscle) to investigate relationships with either absolute tissue weights of carcass fat (CFWT), internal fat (IFWT), and carcass muscle (CMWT), or relative proportions of carcass fat (CFP), internal fat (IFP), and carcass muscle (CMP). Litter growth traits were either unadjusted or adjusted for litter size, to investigate relationships with total lamb burden (total litter birth weight (TBW), total litter weight gain from birth until mid lactation (TWGM), total litter weight gain from birth until weaning (TWGW)) or average lamb performance (average lamb birth weight (ABW), average lamb weight gain from birth until mid lactation (AWGM), average lamb weight gain from birth until weaning (AWGW)).Moderate to large positive genetic correlations were estimated between absolute weights of all three ewe tissues (CFWT, IFWT, CMWT), or muscle proportion (CMP), and litter size (LS). Significant positive genetic correlations were also estimated between weight (CMWT) or proportion (CMP) of muscle carried by the ewe pre-mating and total birth weight (TBW) and weight gains (TWGM, TWGW) of her litter, largely due to the associated increase in litter size. Muscle proportion (CMP) was not significantly correlated to average lamb weights or weight gains (ABW, AWGM, AWGW). Pre-lambing carcass fat weight (CFWT) and proportion (CFP) in the ewe showed positive genetic correlations with average lamb weights and weight gains (ABW, AWGM, AWGW), whereas, after lambing, CFP was negatively correlated with these lamb traits. Internal fat weight (IFWT) pre-mating showed positive genetic correlations with all litter growth traits (TBW, TWGM, TWGW, ABW, AWGM, AWGW). Average lamb growth traits were negatively correlated with pre-lambing internal fat proportion (IFP), but positively correlated to IFP at mid lactation and weaning.Correlations were also estimated between each pair of CT traits. Total internal fat weight and total carcass fat weight were very highly correlated (rp= 0·75,rg= 0·96). Correlations with total carcass muscle weight were smaller and positive for both carcass fat weight (rp= 0·48,rg= 0·12) and internal fat weight (rp= 0·42,rg= 0·20).The results suggest that selection for increased carcass muscle weight or proportion in a Scottish Blackface hill flock would have a positive effect on total weights of litters reared, but that selection against carcass fat weight or proportion in a breeding programme for Blackface sheep may have an impact on the maternal ability of the ewe. However, maintaining fat in internal depots may reduce the depletion of carcass fat during pregnancy, allowing this depot to provide energy for lactation, and may have a positive impact on lamb growth.

MASS SELECTION FOR POST-WEANING GROWTH IN SWINE. V. CORRELATED RESPONSE OF REPRODUCTIVE TRAITS AND PRE-WEANING GROWTH

1976 ◽  
Vol 56 (4) ◽  
pp. 791-801
Author(s):  
I. GARNETT ◽  
G. W. RAHNEFELD
Keyword(s):  
Birth Weight ◽  
Average Daily Gain ◽  
Reproductive Traits ◽  
Correlated Response ◽  
Mass Selection ◽  
Gestation Length ◽  
Control Line ◽  
Weaning Weight ◽  
Selection For ◽  
Daily Gain

Female reproductive performance and pre-weaning survival and growth were examined in a population of swine over 11 generations of selection for post-weaning average daily gain (ADG). Three separate breeding groups were used: (1) a Lacombe (L) line selected each generation for ADG, (2) a Yorkshire control (Y) line, and (3) a crossbred Lacombe × Yorkshire group (LY) generated each generation from the L and Y lines. Breeding group differences were evident for litter size, perinatal mortality, pre-weaning mortality, gestation length, birth weight, pre-weaning average daily gain (PreADG) and weaning weight. Selection did not affect number born, number born alive, number weaned or birth weight. When the values for the L line were expressed as a deviation from the control, pre-weaning mortality showed an increase. The increase appeared to be due to a decrease in the control rather than an increase in the L line. Gestation length showed a negative response to selection. As in the case of pre-weaning mortality, the response appeared to be a reflection of the instability of the control line. Genetic gains in PreADG of 0.004 kg/day/generation were realized in both the L line and LY group. Correspondingly, responses of 0.18 and 0.19 kg/generation were realized for weaning weight in the L line and LY group.

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