Prediction of genetic gains for breeding objective traits and designing selection schemes for Washera and Gumuz indigenous sheep

In Ethiopia,there are 32.85 millions of sheep,more than 99 % of which are indigenous.However,the productivity of local sheep under traditional production system is low with high mortality of sheep.There are two ways of improving performance of sheep and goats,namely improving the enviroment of animals and/or improving there genetic potential.The aim of this study was to predict genetic gains of breedingobjective traits and select the best sheep selection scheme for Gumuz andWashera sheep. Body size(six month weight and yearling weight) and litter size were breeding objective traits identified by own flock animal ranking experiment and personal interview. Deterministic approach of ZPLAN computor program is used for modeling input parametres of Gumuz and Washera sheep and simulating breeding plans using gene flow method and selection index procedures. One-tier cooperative sheep breeding scheme were proposed whereby ram exchange between and within villages is the main means of genetic dissimination. Genetic gains predicted for six month weight of Gumuz and Washera sheep were 0.43 and 0.55 kg,respectively. Genetic gains predicted for yearling weight of Gumuz and Washera sheep were 0.55 and 0.60 kg,respectively. Genetic gains predicted for litter size of Gumuz and Washera sheep were 0.08 and 0.09 lambs,respectively. The lower rate of inbreeding, the higher monetary genetic gain for aggregate genotype,higher return to investmnet and higher profit/ewe/year were quality measures of breeding program considered to prefer scheme 4 for both Gumuz and Washera sheep.Hence,for both Gumuz and Washera sheep populations a sheep selection scheme designed with 15 % selection proportion and one year ram use for breeding was recommended. Special emphasis need to be given to yearling weight with higher predicted genetic response and higher percentage return to investment.

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MOET breeding schemes for wool sheep 2. Selection for adult fleece traits

Animal Science ◽

10.1017/s0003356100007534 ◽

1994 ◽

Vol 59 (1) ◽

pp. 87-98

Author(s):

N. R. Wray ◽

M. E. Goddard

Keyword(s):

Genetic Correlation ◽

Embryo Transfer ◽

Selection Index ◽

Optimum Number ◽

Genetic Response ◽

Breeding Scheme ◽

Merino Sheep ◽

Individual Record ◽

Breeding Programmes ◽

Natural Mating

AbstractBenefits of collection of annual versus a single fleece record are investigated for breeding programmes of Australian Merino sheep. Breeding scheme alternatives are based on natural mating (N) or multiple ovulation and embryo transfer (MOET). The breeding objective is assumed to be an adult fleece trait which is expressed annually from a minimum of age 2 years, with a unity genetic correlation between annual records. Initial selection of parents can occur prior to the availability of their adult records, based on records collected at 6,12 or 18 months which have a maximum genetic correlation of 0·8 with the adult trait. Monte Carlo simulation is used to compare breeding programme alternatives, which allows overlapping generations and selection across age groups. MOET schemes select parents of minimum age 19 months in adult (A) schemes, 7 months in juvenile (J) schemes or 13 months when there are two breeding seasons per year. Natural mating results in an average of 1·09 lambs per ewe mated, whilst embryo transfer success rates follow realistic distributions (only 70% of donors giving live lambs) with an average of 3·45 lambs per donor flushed. Estimated breeding values, on which selection is based, are calculated by multiple trait selection index of an individual's own records or by multivariate best linear unbiased prediction (BLUP). In J schemes 7-month-old lambs may be selected on the basis of a pedigree index if no individual record has been collected at 6 months of age. Breeding scheme alternatives are compared on the basis of genetic response, rate of inbreeding and economic ‘income’ which is calculated as genetic response reduced for inbreeding depression, cumulated and discounted over a medium time horizon (14 years). The quantitative benefits of the collection of annual records are dependent on the choice of genetic and phenotypic parameters between traits, but these were chosen from the literature to be representative of annual fleece weight records in Merino sheep. Genetic response to selection and ‘income’ associated with the adult trait is increased by at least 15% in N, A and J schemes compared with when only a single record is collected at 18 months. The advantage of MOET over N schemes and the optimum number of sires to use is unchanged, but the average age of sires is increased. Both annual rate of inbreeding and average age of dams are unchanged. In N schemes, 80% of the benefits of collecting annual records on both sexes can be achieved by collecting records on males alone, whilst in MOET schemes measurement of dams contributes up to 50% of the benefit of the measurement of both sexes. Since MOET schemes have fewer dams to be recorded, the cost-effectiveness of collecting records on females is much higher than in natural mating schemes. Breeding programmes operating two mating seasons each year are found to be a viable alternative to J schemes: although genetic response is less, rate of inbreeding is also less, so that ‘income’ response is approximately equal.

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Selection for prolificacy in pigs

Proceedings of the British Society of Animal Production (1972) ◽

10.1017/s0308229600014033 ◽

1984 ◽

Vol 1984 ◽

pp. 43-43

Author(s):

E. Avalos ◽

C. Smith ◽

M. Bichard

Keyword(s):

Litter Size ◽

Selection Index ◽

Generation Interval ◽

Sire Family ◽

Males And Females ◽

Selection For ◽

One Year

Pigs can be bred at 6 months of age. By this time it is possible for their dams to have two litter records (at 12 months and 18 months of age) on which selection for litter size can be based. Hence, a generation interval of one year for both males and females can be achieved. Ollivier (1974), has shown that this system maximizes the rates of response. The accuracy with which replacements are chosen can be increased further by including information from other relatives (dam and sire family) in a selection index.

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Multistage selection for genetic gain by orthogonal transformation.

Genetics ◽

10.1093/genetics/129.3.963 ◽

1991 ◽

Vol 129 (3) ◽

pp. 963-974 ◽

Cited By ~ 1

Author(s):

S Z Xu ◽

W M Muir

Keyword(s):

Selection Index ◽

Orthogonal Transformation ◽

Cost Savings ◽

Breeding Value ◽

Economic Returns ◽

Selection Scheme ◽

Genetic Gains ◽

Independent Culling ◽

Total Proportion ◽

Multistage Selection

Abstract An exact transformed culling method for any number of traits or stages of selection with explicit solution for multistage selection is described in this paper. This procedure does not need numerical integration and is suitable for obtaining either desired genetic gains for a variable proportion selected or optimum aggregate breeding value for a fixed total proportion selected. The procedure has similar properties to multistage selection index and, as such, genetic gains from use of the procedure may exceed ordinary independent culling level selection. The relative efficiencies of transformed to conventional independent culling ranged from 87% to over 300%. These results suggest that for most situations one can chose a multistage selection scheme, either conventional or transformed culling, which will have an efficiency close to that of selection index. After considering cost savings associated with multistage selection, there are many situations in which economic returns from use of independent culling, either conventional or transformed, will exceed that of selection index.

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The impact of maternal genetic merit and country of origin on ewe reproductive performance, lambing performance and ewe survival

Translational Animal Science ◽

10.1093/tas/txab070 ◽

2021 ◽

Author(s):

N Fetherstone ◽

N McHugh ◽

T M Boland ◽

F M McGovern

Keyword(s):

New Zealand ◽

Birth Weight ◽

Litter Size ◽

Country Of Origin ◽

Reproductive Traits ◽

Gestation Length ◽

Genetic Merit ◽

Genetic Groups ◽

One Year ◽

The Impact

Abstract The objective of this study was to investigate the impact of the ewe’s maternal genetic merit and country of origin (New Zealand or Ireland) on ewe reproductive, lambing and productivity traits. The study was performed over a four year period (2016 to 2019) and consisted of three genetic groups: high maternal genetic merit New Zealand (NZ), high maternal genetic merit Irish (High Irish) and low maternal genetic merit Irish (Low Irish) ewes. Each group contained 30 Suffolk and 30 Texel ewes, selected based on the respective national maternal genetic indexes; i.e. either the New Zealand Maternal Worth (New Zealand group) or the €uro-star Replacement index (Irish groups). The impact of maternal genetic merit on reproductive traits such as litter size; lambing traits such as gestation length, birth weight, lambing difficulty, mothering ability, and productivity traits such as the number of lambs born and weaned were analyzed using linear mixed models. For binary traits, the impact of maternal genetic merit on reproductive traits such as conception to first AI service; lambing traits such as dystocia, perinatal lamb mortality and productivity traits such as ewe survival were analyzed using logistic regression. New Zealand ewes outperformed Low Irish ewes for conception to first AI (P<0.05) and litter size (P=0.05). Irish ewes were more likely to suffer from dystocia (6.84 (High Irish) and 8.25 (Low Irish) times) compared to NZ ewes (P<0.001); birth weight and perinatal mortality did not differ between groups (P>0.05). Lambs born from NZ ewes were 4.67 (95% CI: 1.89 to 11.55; P<0.001) and 6.54 (95% CI: 2.56 to 16.71; P<0.001) times more likely to stand up and suckle unassisted relative to lambs born from High or Low Irish ewes, respectively. New Zealand and High Irish ewes had a greater number of lambs born and weaned throughout the duration of the study compared to their Low Irish counterparts (P<0.001). New Zealand ewes tended to be more likely to survive from one year to the next compared to Low Irish ewes (P=0.07). Irish ewes of high maternal genetic merit outperformed their Low counterparts in total number of lambs born and weaned per ewe, but performance did not differ across other traits investigated. This highlights the importance of continuous development of the Irish maternal sheep index to ensure favourable improvements in reproductive, lambing and productivity traits at farm level. Overall, results demonstrate the suitability of NZ genetics in an Irish production system.

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Claw health and feed efficiency as new selection criteria in the Czech Holstein cattle Krupová Z., Wolfová M., Krupa E., Přibyl J., Zavadilová L.

Czech Journal of Animal Science ◽

10.17221/44/2018-cjas ◽

2018 ◽

Vol 63 (No. 10) ◽

pp. 408-418 ◽

Cited By ~ 1

Author(s):

Z. Krupová ◽

M. Wolfová ◽

E. Krupa ◽

J. Přibyl ◽

L. Zavadilová

Keyword(s):

Feed Intake ◽

Feed Efficiency ◽

Disease Incidence ◽

Selection Index ◽

Residual Feed Intake ◽

Selection Response ◽

Holstein Cattle ◽

Breeding Objective ◽

Economic Weights ◽

The Impact

The objective of this study was to calculate economic weights for ten current breeding objective traits and for four new traits characterising claw health and feed efficiency in Czech Holstein cattle and to investigate the impact of different selection indices on the genetic responses for these traits. Economic weights were estimated using a bio-economic model, while applying actual (2017) and predicted (2025) production and economic circumstances. For the actual situation, the economic weights of claw disease incidence were –100.1 € per case, and those of daily residual feed intake in cows, breeding heifers, and fattened animals were –79.37, –37.16, and –6.33 €/kg dry matter intake per day, respectively. In the predicted situation, the marginal economic weights for claw disease and feed efficiency traits increased on average by 38% and 20%, respectively. The new traits, claw disease incidence and daily residual feed intake, were gradually added to the 17 current Holstein selection index traits to improve the new traits. Constructing a comprehensive index with 21 traits and applying the general principles of the selection index theory, a favourable annual genetic selection response was obtained for the new traits (–0.008 cases of claw disease incidence and –0.006 kg of daily residual feed intake across all cattle categories), keeping the annual selection response of the most important current breeding objective traits at a satisfactory level (e.g., 73 kg of milk yield per lactation, 0.016% of milk fat). Claw health and feed efficiency should be defined as new breeding objectives and new selection index traits of local dairy population.

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Selection and response within the nucleus of a sheep group-breeding scheme

Animal Science ◽

10.1017/s0003356100012630 ◽

1990 ◽

Vol 51 (3) ◽

pp. 593-599 ◽

Cited By ~ 2

Author(s):

S. Anderson ◽

M. K. Curran

Keyword(s):

Litter Size ◽

Age Groups ◽

Selection Response ◽

Sheep Flock ◽

Breeding Scheme ◽

Average Value ◽

Group Breeding ◽

Selection For ◽

Progeny Group ◽

Selection Differentials

ABSTRACTAn evaluation of the response to selection for prolificacy within a nucleus sheep flock of a commercial group-breeding scheme is presented. In 1979, the Romney Group Breeders formed a nucleus flock of 120 prolific ewes chosen from 12 contributing flocks. A control flock was established in 1982 from the same source. The analysis was conducted on the trait of litter size. Selection differentials are presented for each year of birth progeny group in both flocks. Expected selection response was calculated from selection differentials and was found to have an average value of 1·5% of parent mean litter size per year. Using least squares procedures the litter size performance of control and nucleus ewes of 2, 3 and 4 years of age was corrected for environmental effects. Realized response was estimated from the differences between corrected litter size means of control and nucleus flocks. Response in litter size was found to be significant within years and within ewe age groups (P < 0·05).

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Yield traits as selection indices in seedling populations of cassava

Cropp Breeding and Applied Biotechnology ◽

10.1590/s1984-70332010000300002 ◽

2010 ◽

Vol 10 (3) ◽

pp. 191-196 ◽

Cited By ~ 11

Author(s):

Henry Fred Ojulong ◽

Maryke Tine Labuschagne ◽

Liezel Herselman ◽

Martin Fregene

Keyword(s):

Dry Matter ◽

Tuber Yield ◽

Selection Index ◽

Matter Content ◽

Root Weight ◽

Dry Matter Content ◽

Root Yield ◽

Breeding Scheme ◽

Selection Indices ◽

Root Quality

The cassava breeding scheme currently used is long, because initial stages concentrate mainly on improving yield, with root quality selection following later. To shorten the scheme, yield and root quality should be selected simultaneously, starting at the seedling nursery. In this study, a nursery comprising of eight cassava families and 1885 seedlings developed from parents adapted to three major agro-ecologies, were evaluated for yield related traits in Colombia. Percentage dry matter content (DMC) and harvest index produced similar ranking of the parents. Tuber yield, weight, and number showed potential of increasing yield through conventional breeding. A selection index including fresh root yield, percentage DMC, root weight and roots per plant, with heavier weights being assigned to root weight and roots per plant, should be used.

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Heterosis in the second and third generation affects litter size in a crossbreed mink (Neovison vison) population

Archives of Biological Sciences ◽

10.2298/abs1403097t ◽

2014 ◽

Vol 66 (3) ◽

pp. 1097-1103 ◽

Cited By ~ 2

Author(s):

Janne Thirstrup ◽

Cino Pertoldi ◽

Peter Larsen ◽

Vivi Nielsen

Keyword(s):

Litter Size ◽

Maternal Effects ◽

Inbreeding Depression ◽

Neovison Vison ◽

Parental Line ◽

Third Generation ◽

Black Line ◽

Environmental Variations ◽

The Mean ◽

One Year

Litter sizes in a cross between Brown and Black mink color types were observed through six generations. Litter size was significantly affected by yearly environmental variations. After adjusting for year effects, we found significant increases in litter size in the second and third generations (F2 and F3) after crossing. Thereafter, in the following generations, litter size dropped to a level comparable to the mean litter size of the midparent. Increased litter size in F2 compared to F1 indicated that maternal effects influenced litter size more than non-maternal effects. The heterosis was mainly caused by an increase in litter size compared to the Black parental line. This indicates that the Black line was affected by inbreeding depression prior to crossing. We also found that two-year old F1 females had significantly more offspring compared to one-year old F1 females.

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Association of gdf9 Gene Polymorphisms With Litter Size in Indigenous Sheep of Bangladesh

Research in Agriculture Livestock and Fisheries ◽

10.3329/ralf.v7i2.48871 ◽

2020 ◽

Vol 7 (2) ◽

pp. 283-292

Author(s):

Faruk Hossain ◽

Sharmin Akter Suma ◽

Mohammad Shamsul Alam Bhuiyan

Keyword(s):

Gene Polymorphism ◽

Litter Size ◽

Gene Polymorphisms ◽

Climatic Conditions ◽

Animal Protein ◽

Selection Program ◽

Indigenous Sheep ◽

Gdf9 Gene

Sheep in Bangladesh are well known as efficient users of low quality roughages, welladapted to hot and humid agro-climatic conditions, capable of bi-annual lambing withmultiple births and resistant to common prevalent diseases. They play an important role inthe supply of animal protein. Present study aimed to investigate possible association ofGDF9 gene polymorphisms with litter size. A total of 126 DNA samples extracted from theblood of indigenous sheep from 5 locations namely Tangail, Noakhali, Naogaon,Gaibandha and Satkhira with known litter size were used to study the association ofGDF9 polymorphism by PCR based RFLP method. Two polymorphic regions of GDF9(FecG1 and FecG8) were amplified by PCR, digested with respective restriction enzymesand 126 sheep were genotyped. Current study revealed that genotype and allelefrequency for FecG1 varied among the sheep from different locations. The genotype (GG,AG, AA) frequency were 51.59%, 45.24% and 3.17% and the allele (G and A) frequenciesin the overall population were 74.21% and 25.79%, respectively. There was a significantassociation of FecG1 of GDF9 gene polymorphism with litter size. The homozygous GGgenotype had the lowest litter size (1.59±0.09; n=65) and homozygous AA genotype hadthe highest litter size (2.00±0.41; n=4). No genotypic variations were found for FecG8.Findings of this study specially the polymorphism of FecG1 together with genotyping ofsome sheep could be utilized in the selection program to increase the lamb productionpotentiality of indigenous sheep of Bangladesh. Res. Agric., Livest. Fish.7(2): 283-292, August 2020

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