Community-based breeding programs (CBBPs) for small ruminants have been suggested as alternatives to centralised, government-controlled breeding schemes which have been implemented in many developing countries. An innovative methodological framework on how to design, implement and sustain CBBPs was tested in three sites in Ethiopia: Bonga, Horro and Menz. In these CBBPs, the main selection trait identified through participatory approaches was 6-month weight in all three sites. In Horro and Bonga, where resources such as feed and water permitted larger litter sizes, twinning rate was included. Ten-year (2009 to 2018) performance data from the breeding programs were analysed using Average Information Restricted Maximum Likelihood method (AI-REML). Additionally, the socioeconomic impact of CBBPs was assessed. Results indicated that 6-month weight increased over the years in all breeds. In Bonga, the average increase was 0.21 ± 0.018 kg/year, followed by 0.18 ± 0.007 and 0.11 ± 0.003 kg/year in Horro and Menz, respectively. This was quite substantial in an on-farm situation. The birth weight of lambs did not improve over the years in Bonga and Horro sheep but significant increases occurred in Menz. Considering that there was no direct selection on birth weight in the community flock, the increased weights observed in Menz could be due to correlated responses, but this was not the case in Bonga and Horro. The genetic trend for prolificacy over the years in both Bonga and Horro flocks was positive and significant (P < 0.01). This increase in litter size, combined with the increased 6-month body weight, increased income by 20% and farm-level meat consumption from slaughter of one sheep per year to three. The results show that CBBPs are technically feasible, result in measurable genetic gains in performance traits and impact the livelihoods of farmers.

The objectives of this study were to estimate the genetic parameters and genetic trends for different measures of persistency (PM) for milk yield in Iranian buffaloes using a random regression test day model. Test day records of the first three lactations of buffaloes within 715 herds comprising 43 014, 38 941 and 33 937 records, respectively, were obtained from the Animal Breeding Center of Iran during 1992 to 2012. Legendre polynomial functions were chosen to fit the lactation curves in the framework of a random regression test day model for estimating (co)variance components. Three measures of persistency were modified based on the lactation curve conditions of buffaloes: (1) The average of estimated breeding values (EBVs) for test day milk yields from day 226 to day 270 as a deviation from the average of EBVs from day 44 to day 62 (PM1), (2) A summation of contribution for each day from day 53 to day 247 as a deviation from day 248 (PM2), (3) The difference between EBVs for day 257 and day 80 (PM3). The highest heritability estimates were observed for PM2 over the first three lactations (0·29, 0·80 and 0·42, respectively). Estimates of genetic correlations between persistency measures and milk yield varied from −0·48 to 0·29 (first lactation), from −0·12 to 0·48 (second lactation), and from −0·62 to 0·63 (third lactation). Estimate of genetic trend for first lactation PM2 was negative (−0·0088 ± 0·0043; P < 0·05). It is essential to include milk yield persistency in the breeding goal of Iranian buffaloes along with other important traits such as milk yield or reproductive traits.

The objective of this study was to analyse the effectiveness of genetic improvement via domestic selection and import for backfat thickness and time on test in a conventional pig breeding programme for Landrace (L) and Large-White (LW) breeds. Phenotype data was available for 25 553 L and 10 432 LW pigs born between 2002 and 2012 from four large-scale farms and 72 family farms. Pedigree information indicated whether each animal was born and registered within the domestic breeding programme or has been imported. This information was used for defining the genetic groups of unknown parents in a pedigree and the partitioning analysis. Breeding values were estimated using a Bayesian analysis of an animal model with and without genetic groups. Such analysis enabled full Bayesian inference of the genetic trends and their partitioning by the origin of germplasm. Estimates of genetic group indicated that imported germplasm was overall better than domestic and substantial changes in estimates of breeding values was observed when genetic group were fitted. The estimated genetic trends in L were favourable and significantly different from zero by the end of the analysed period. Overall, the genetic trends in LW were not different from zero. The relative contribution of imported germplasm to genetic trends was large, especially towards the end of analysed period with 78% and 67% in L and from 50% to 67% in LW. The analyses suggest that domestic breeding activities and sources of imported animals need to be re-evaluated, in particular in LW breed.

The aim of this study was to investigate the effect of including milk yield data in the international genetic evaluation of female fertility traits to reduce or eliminate a possible bias because of across-country selection for milk yield. Data included two female fertility traits from Great Britain, Italy and the Netherlands, together with milk yield data from the same countries and from the United States, because the genetic trends in other countries may be influenced by selection decisions on bulls in the United States. Potentially, female fertility data had been corrected nationally for within-country selection and management biases for milk yield. Using a multiple-trait multiple across-country evaluation (MT-MACE) for the analysis of female fertility traits with milk yield, across-country selection patterns both for female fertility and milk yield can be considered simultaneously. Four analyses were performed; one single-trait multiple across-country evaluation analysis including only milk yield data, one MT-MACE analysis including only female fertility traits, and one MT-MACE analysis including both female fertility and milk yield traits. An additional MT-MACE analysis was performed including both female fertility and milk yield traits, but excluding the United States. By including milk yield traits to the analysis, female fertility reliabilities increased, but not for all bulls in all the countries by trait combinations. The presence of milk yield traits in the analysis did not considerably change the genetic correlations, genetic trends or bull rankings of female fertility traits. Even though the predicted genetic merits of female fertility traits hardly changed by including milk yield traits to the analysis, the change was not equally distributed to the whole data. The number of bulls in common between the two sets of Top 100 bulls for each trait in the two analyses of female fertility traits, with and without the four milk yield traits and their rank correlations were low, not necessarily because of the absence of the US milk yield data. The joint international genetic evaluation of female fertility traits with milk yield is recommended to make use of information on several female fertility traits from different countries simultaneously, to consider selection decisions for milk yield in the genetic evaluation of female fertility traits for obtaining more accurate estimating breeding values (EBV) and to acquire female fertility EBV for bulls evaluated for milk yield, but not for female fertility.

In genetic evaluations, the definition of unknown parent groups (UPG) is usually based on time periods, selection path and flows of foreign founders. The definition of UPG may be more complex for populations presenting genetic heterogeneity due to both, large national expansion and coexistence of artificial insemination (AI) and natural service (NS). A UPG definition method accounting for beef bull flows was proposed and applied to the French Charolais cattle population. It assumed that, at a given time period, unknown parents belonged to the same UPG when their progeny were bred in herds that used bulls with similar origins (birth region and reproduction way). Thus, the birth period, region and AI rate of a herd were pointed out to be the three criteria reflecting genetic disparities at the national level in a beef cattle population. To deal with regional genetic disparities, 14 regions were identified using a factorial approach combining principal component analysis and Ward clustering. The selection nucleus of the French cattle population was dispersed over three main breeding areas. Flows of NS bulls were mainly carried out within each breeding area. On the contrary, the use and the selection of AI bulls were based on a national pool of candidates. Within a time period, herds of different regions were clustered together when they used bulls coming from the same origin and with an estimated difference of genetic level lower than 20% of genetic standard deviation (σg) for calf muscle and skeleton scores (SS) at weaning. This led to the definition of 16 UPG of sires, which were validated as robust and relevant in a sire model, meaning numerically stable and corresponding to distinct genetic subpopulations. The UPG genetic levels were estimated for muscle and SS under sire and animal models. Whatever the trait, differences between bull UPG estimates within a time period could reach 0.5 σg across regions. For a given time period, bull UPG estimates for muscle and SS were generally larger by 0.30 to 0.75 σg than those of cows. Including genetic groups in the evaluation model increased the estimated genetic trends by 20% to 30%. It also provoked re-ranking in favor of bulls and cows without pedigree.

An experimental design aiming at analysing the consequences of genetic selection from 1977 to 1998–2000 on the evolution of stress-responsive systems in the French Large White (LW) and Landrace (LR) pig populations was conducted by INRA and IFIP-Institut du Porc. Large White sows were inseminated with semen from LW boars born in 1977 (frozen semen) or in 1998 and their second-generation offspring were station-tested. Landrace sows were inseminated with semen from LR boars born in 1977 (frozen semen) or in 1999 to 2000, and their progeny was station-tested. Urinary concentration of stress hormones (cortisol and catecholamines) and traits related to carcass composition (estimated carcass lean content (ECLC) and global adiposity) and meat quality (pH 24 h) were measured. For the two populations, selection carried out since 1977 led to an increase in ECLC and a decrease in carcass adiposity. Between 1977 and 1998 to 2000, urinary concentrations of stress hormones were unchanged in the LR breed, but were decreased in the LW breed. Moreover, for the animals generated from LW boars born in 1977 and in 1998, urinary cortisol levels were negatively correlated with ECLC. Therefore, in the LW breed, selection carried out for higher ECLC resulted in a decrease in cortisol production, as well as a reduction of catecholamine production that may be responsible for the lower ultimate pH of meat. Therefore, selection carried out for increased carcass lean content led, in this breed, to large modifications in the functioning of the stress-responsive systems, thereby influencing a large range of physiological regulations and technical properties such as carcass composition and meat pH, which remained however in the normal range for acceptable meat quality.

In this note, a procedure to partition the genetic trend of a selected population is presented. Each part of the genetic gain accounts for the Mendelian sampling terms of different groups of animals, which can be sometimes assigned to different selection policies. The method is based on a simple transformation of the predicted breeding values. The procedure was illustrated with two simulated examples. In the first example, the genetic trend is partitioned into two pieces, one coming from the selection on sires and the other coming from the selection on dams. The second example shows how the impact of an artificial insemination center in the genetic gain of the whole population can be evaluated.

The objective of the study was to estimate genetic trends from 1977 to 1998 in the French Large White (LW) breed for stillbirth and associated traits measured at farrowing using frozen semen. Two groups of pigs (G77 and G98) were obtained by inseminating LW sows with semen from LW boars born either in 1977 or in 1998. A second generation was produced by inter se mating in each group. Farrowing was thoroughly supervised through both direct observations and video recording all long farrowing on a total of 137 first- and second-parity litters produced by sows from this second generation (68 G77 and 69 G98 litters, respectively). Measurements included birth time, weight and birth characteristics (including orientation, presence of cyanosis or oedema, membrane obstruction, umbilical cord length/content) of each piglet, as well as sow traits (weight and backfat thickness, farrowing duration, litter size and within-litter variation of weights at birth). The data were analysed using linear or generalised linear mixed models, according to the definition of the trait (continuous or binary data). The importance of several effects to piglet probability of stillbirth was then quantified by computing the reduction of variance associated with the addition of each effect in the model. Litter size did not significantly differ in first parity, but was higher in G98 second-parity sows: the differences for global (including pre partum dead piglets) and total numbers of piglets born per litter were +2.3 ± 1.1 and +1.3 ± 0.6, respectively. G98 sows also had a higher number of stillbirths in both parities (+0.7 ± 0.3 stillborn per litter). Piglets from G98 litters were heavier at birth (+130 ± 40 g for birth weight adjusted for litter size), without any increase in within-litter heterogeneity of birth weight. No significant difference was detected between G77 and G88 groups for farrowing length and the distribution of time interval between piglet births. G98 stillborn piglets had longer and more often empty umbilical cords at birth. G98 piglets born alive also had more often umbilical nodes than G77 piglets. These characteristics were considered as indicators of increased farrowing difficulties and risk of hypoxia at birth in G98 pigs. Time of birth of each piglet, sow fatness at farrowing and time of first placenta expulsion were the main factors of variation of the piglet’s probability of stillbirth.

This paper reports the procedures put into place in the UK for the genetic evaluation of pedigree beef cattle and estimation of genetic trends using a comprehensive model to allow critical analysis of progress made under previous data recording schemes. Live weights of Simmental, Limousin, Charolais, South Devon and Aberdeen Angus beef cattle, recorded by the Meat and Livestock Commission (MLC) from 1970 to 1992 were analysed, as part of a project to introduce best linear unbiased predictions (BLUP) of breeding value in the British beef industry. Birth weights were available from MLC or the relevant breed society, (4000 to 84000 records, depending on the breed) and 200- and 400-day weights were estimated by within-animal linear regression on all available weights (resulting in 8000 to 48000 records per breed). Animals were retrospectively assigned to contemporary groups within herds, separately for each trait, taking account of observed calving patterns. Records were adjusted to correct for heterogeneity of variance between herds. BLUP evaluations were then performed within breed, fitting a multivariate individual animal model. In addition to additive direct genetic effects, additive maternal genetic and dam permanent environmental effects were included for birth weight and 200-day weight. Unknown parents were assigned to genetic groups, based on estimated date of birth. The model included fixed effects for contemporary group, sex, month of birth, birth type (single or multiple), embryo transfer births, fostered calves, breed of dam, proportion purebred and age of dam. Genetic trends were estimated by regressing estimated breeding values for animals on their year of birth. Trends in birth weight, 200-day weight and 400-day weight between 1970 and 1992 were approximately 0·09, 0·73 and 1·38 kg per annum respectively for the Charolais breed; 0·08, 0·76 and 1·33 kg per annum for the Simmental; 0·06, 0·53 and 0·89 kg per annum for the Limousin; 0·12, 1·02 and 1·86 kg per annum for the Aberdeen Angus; and 0·03, 0·38 and 0·82 kg per annum for the South Devon breed.

A selection programme was set up in 1983 in the Ivory Coast to improve the growth and live weight of the indigenous Djallonkè sheep using an open nucleus breeding system. Selection was based on male individual weights at 80, 180 and 365 days of age. Multiple sires were used in farmers' flocks. Individual animal model, using average numerator relationship was used to estimate breeding values from which genetic trends were derived. This paper reports results of the analyses of 10 417 records of 80-day weights (WT80) of lambs born between 1984 and 1992 from 29 participating farmers, and 1978 and 849 records on 180- (WT180) and 365- (WT365) day weights, respectively, of lambs from the nucleus. Phenotypic trends exhibited substantial annual fluctuation during the study period. The heaviest weights were obtained in 1986 (10·1 kg) for WT80, 1984 (23·3 kg) for WT180 and 1985 (33·7 kg) for WT365. There was an annual decline of 152 g (P<0·05) in WT80 mainly (–180 g/year) due to negative environmental trend. The phenotypic and environmental trends for WT180 were –703 and –721 g/year, respectively, while the corresponding values for WT365 were –931 and –956 g/year. Overall mean weights of the ram lambs at the three ages were 9·9, 23·3 and 33·7 kg, respectively in the base year and 9·3, 17·8 and 28·2 kg, respectively in the final year. Breeding values increased by 28, 11 and 14 g/year for WT80, WT180 and WT365, respectively. Results of this study indicate that genetic progress can be made in growth performance of Djallonkè sheep if reasonable levels of animal management as well as selection pressure are maintained.

Records on total of 1746 calvings of principally Milking Criollos and their crosses were collected between 1972 and 1990 at the experiment station of the Mexican Association of Animal Production on the Gulf Coast of Mexico. Traits of interest were 305-day milk yield, days in lactation, number of services per lactation (raised to power 1/2), age at first calving and lifetime milk yield. Data were analysed by restricted maximum likelihood (REML) under an individual animal model based on 584 animals of which 146 were female ancestors and 35 were male ancestors. Heritabilities of 305-day milk and age at first calving were 0·17 and 0·07, respectively, but heritabilities of other traits were close to zero. Genetic trend in the Milking Criollos for 305-day milk was small and not significant (0·76 (s.e. 2·38) kg/year). Of crosses with Criollo sires, those involving Holstein and Canadienne breeding had highest 305-day and lifetime milk yields and those involving Brown Swiss and native Mexican (mostly Oaxaca) had lowest yields. Jersey crosses were intermediate for 305-day yield. The F1 Criollo × Jersey cross had highest lifetime yield, but backcrosses involving Jersey breeding were poor for lifetime milk. Additive breed effects for Jersey and Canadienne, relative to Milking Criollo, were 88 (s.e. 91) and 227 (s.e. 74) kg 305-day milk, respectively. Heterosis was 144 (s.e. 55) kg (11·6%) for 305-day milk, 16–4 (s.e. 9·6) (5·0%) for days in milk, −0·107 (s.e. 0–042) (7·7%) for number of services per lactation raised to power 1/2, −25·6 (s.e. 41·4) days (2•3%) for age at first calving and 1789 (s.e. 664) kg (60·0%) for lifetime milk. A plan was designed to develop a nucleus breeding scheme utilizing multiple ovulation and embryo transfer technology (MOET) for the genetic improvement of the Milking Criollo breed in Mexico.

Breeding programmes for Wakwa and Ngaundere Gudali cattle breeds were initiated in Wakwa (Cameroon) in 1952 and 1965, respectively, to improve growth performance of the indigenous breeds. Animals were selected on 240-day weaning weight (WWT). Data analysed covered the period 1971 through 1985 and consisted of 2211 calf birth weight (BWT) and 1409 WWT records on Gudali and 1196 BWT and 763 WWT records on Wakwa. Selection responses in BWT and WWT were estimated as regressions of average sire estimated transmitting abilities (ETAs) and average dam estimated breeding values (EBVs) on year of calving. ETAs and EBVs were predicted using best linear unbiased prediction procedures. Estimated annual changes in sire ETAs for WWT were 0·67 (s.e. 0·17) and 1·69 (s.e. 1·13) kg/year for Gudali and Wakwa, respectively. Corresponding trends in dam EBVs were –0·03 (s.e. 0·03) and –0·24 (s.e. 0·19) kg/year. Estimated correlated trends in BWT among Gudali and Wakwa sires were 0·09 (s.e. 0·05) and –0·14 (s.e. 0·04) kg/year, respectively. Corresponding correlated trends in BWT associated with dam selection were essentially zero, being –0·001 (s.e. 0·001) and –0·01 (s.e. 0·01) kg/year. Environmental trends were negative for all traits except Gudali WWT. Phenotypic trends were all positive, except that of Wakwa BWT. Overall, selection on WWT yielded moderate selection reponse despite substantial infrastructural constraints in the breeding programme. Trends in sire ETAs and dam EBVs for WWT jointly accounted for estimated genetic gains of 8·60 kg in Gudali and 20·4 kg in Wakwa over the study period. Overall correlated response in BWT during the study period was significant (P < 0·001) and negative for Wakwa. It was positive but not significant for Gudali.