The study, published in Veterinary Medicine and Science, examined growth performance within community-based breeding programmes, or CBBPs, established in 2018 in the villages of Addis Mender and Alquzu in the Sekota and Ziquala districts. This participatory approach to breed improvement, widely regarded as the most sustainable model for tropical smallholder systems, puts selection decisions directly in the hands of farmers while researchers supply the performance data and genetic tools. Enumerators recorded birth weights within 24 hours of kidding and tracked growth at standardized ages of 90, 180, 270 and 360 days, adjusting all weights to fixed ages so that a kid weighed at 110 days could be fairly compared with one weighed at 95.

The headline numbers tell a story of modest but meaningful production. Average birth weight across the flock was about 2.3 kilograms, rising to roughly 7.5 kilograms at three months, 8.8 kilograms at six months, 12.1 kilograms at nine months, and 15.3 kilograms at one year. Average daily gain peaked at 58.2 grams per day from birth to weaning, then fell steeply, halving between three and six months and dwindling to just 10.5 grams per day from nine months to yearling age. This declining trajectory, the authors note, is expected: pre-weaning growth is driven largely by the dam’s milk production and mothering ability, while post-weaning growth depends more on the animal’s own genetic potential and the increasingly unforgiving environment.

That environment is punishing. The Ziquala district receives between 250 and 650 millimetres of rain, compressed into a brief and erratic window from July to August, and temperatures swing from 25 to 39 degrees Celsius. Kids born in the wet season consistently outgrew their dry-season counterparts at every measured age, with three-month weights of 8.0 versus 7.6 kilograms and yearling weights of 15.8 versus 14.6 kilograms. Village effects were equally striking: Addis Mender kids significantly outgrew those in Alquzu at every post-birth stage, a gap the researchers attribute to better feed management, the use of improved cowpea forage, and traditional livestock mobility along the Tirari river that lets herders chase surplus grazing in times of shortage.

Sex, birth type and parity also left their fingerprints on the data. Male kids were heavier than females at birth and at most later ages, a difference the authors ascribe to hormonal influences. Single-born kids edged out twins at birth and three months, plausibly reflecting limited uterine space and prenatal nutrient competition, but this advantage evaporated by nine months and one year, an encouraging finding that suggests encouraging twin births carries no long-term growth penalty. That matters in a breed where twinning rates are only about 10 percent and kidding intervals stretch to 11.3 months, limiting each doe to roughly one kid per year.

The genetic core of the study lies in its heritability estimates, calculated using mixed univariate animal models in the Wombat software, with four competing models tested via likelihood ratio tests to properly partition direct additive, maternal genetic and maternal permanent environmental effects. Direct heritability estimates ranged from 0.34 for birth weight to 0.45 for three-month weight, with six-month, nine-month and yearling weights falling between 0.40 and 0.42. These moderate to high values carry a powerful practical implication: a substantial fraction of the variation in growth is genetically driven, meaning that selecting the best bucks as sires should yield real, measurable progress across generations.

The pattern of maternal effects proved equally instructive. When maternal genetic effects were included in the models, direct heritability estimates dropped, confirming that ignoring dam contributions inflates apparent genetic merit and biases breeding value predictions. Maternal heritability for early growth rate traits reached 0.24, and maternal permanent environmental effects, capturing the lasting imprint of uterine conditions, milk yield and early-life care, accounted for 5 to 16 percent of phenotypic variance. Genetic correlations between direct growth effects and maternal performance were strongly positive, between 0.86 and 0.96, suggesting that genes which make kids grow faster also tend to make their dams better mothers, allowing simultaneous improvement of both through selection, though the authors caution that such high covariance estimates can carry large sampling errors with limited pedigree depth.

Perhaps the most actionable finding concerns which traits breeders should target. Birth weight showed only weak genetic correlations with later growth stages, ranging from 0.09 to 0.23, indicating that selecting on birth weight alone would do little to improve yearling size. In contrast, three-month weight exhibited high positive genetic correlations with six-month weight (0.87), nine-month weight (0.67) and yearling weight (0.71). This opens the door to indirect early selection: kids carrying genes for superior growth reveal themselves clearly by weaning age, letting breeders cull and choose months before the animals reach market weight, accelerating the entire selection cycle.

Against regional benchmarks, Abergelle goats remain modest performers. Their birth weights lag the Central Highland breed, their six-month weights fall well short of Woyto-Guji, Bati and Borana goats, and their early daily gains trail those recorded for the same breed under semi-intensive management. But the comparison is not simply a matter of inferior genetics; Abergelle goats survive and reproduce in some of the most marginal agro-ecologies in the Amhara region, browsing Acacia-dominated shrubland where crop farming fails. The moderate heritabilities found here suggest the breed is not genetic dead weight but a locally adapted resource waiting for better selection pressure.

The authors’ diagnosis of the programme’s uneven progress is refreshingly candid. Weight traits did not increase linearly across the six study years, and they point to gaps in accurate buck selection, premature sale of breeding sires, inconsistent enumerator training, and year-to-year feed fluctuations as the likely culprits. Their prescriptions are concrete: tighten sire selection using estimated breeding values, which has been standard practice since 2020; increase selection intensity beyond the current top-10-percent retention of bucks; rotate breeding bucks annually across flocks to keep inbreeding at zero; and shift selection decisions earlier, to six months of age. For a country where sheep and goats supply 242,774 tonnes of the national meat supply and goat meat demand from urban kurete houses and hotels is climbing, squeezing faster growth out of a breed that already thrives where nothing else will may be one of the most quietly consequential wins in African livestock science.

Subject of Research: Genetic and phenotypic parameters of growth traits in Abergelle goats under community-based breeding programmes in north-eastern Ethiopia

Article Title: The Estimation of Phenotypic and Genetic Parameters for Growth Rate Traits of Abergelle Goat Under the Community‐Based Breeding Programme in the North‐Eastern Parts of Ethiopia

Article References: Abebe, Y. W., Meberatie, W. S., & Wondie, Z. T. (2026). The Estimation of Phenotypic and Genetic Parameters for Growth Rate Traits of Abergelle Goat Under the Community‐Based Breeding Programme in the North‐Eastern Parts of Ethiopia. Veterinary Medicine and Science, 12(5), Article e71202. https://doi.org/10.1002/vms3.71202

Image Credits: AI Generated

DOI: 10.1002/vms3.71202

Keywords: Abergelle goats, heritability, community-based breeding programme, Ethiopia, growth traits, genetic parameters, average daily gain, maternal effects, animal breeding, small ruminants, selective breeding, Wag-Himera

Ethiopia is home to approximately 44.9 million sheep, one of the largest national populations in Africa, and small ruminants provide critical support to rural livelihoods, food security, and household income. Yet the productivity of these flocks is chronically constrained by feed shortages in both quantity and quality. Seasonal fluctuations in forage availability mean that growing lambs often fail to receive sufficient nutrients during the most demanding phase of their development. The consequences are severe: reduced growth rates, depressed weaning weights, greater susceptibility to disease, and lamb mortality rates that have been reported to range from 15 to 30 percent under traditional production systems. Because early-life performance exerts a profound influence on subsequent growth, reproductive potential, and lifetime productivity, the pre-weaning period represents a decisive window in which nutritional interventions can pay dividends for months or even years afterward.

The biology underlying this window is well established. During the first weeks of life, lambs rely almost entirely on their dam’s milk, but as they begin to nibble solid feed, a cascade of developmental events is set in motion within the rumen. Microbial colonization begins, the ruminal papillae that line the organ’s wall start to develop, and the rumen undergoes functional maturation that enables the animal to transition from a liquid, milk-based diet to efficient utilization of solid feed. Fermentation of starter feeds produces volatile fatty acids, particularly butyrate and propionate, which stimulate the development of the ruminal epithelium and improve digestive capacity after weaning. In theory, then, providing young lambs with an appropriate solid supplement should accelerate this developmental program and buffer them against the nutrient shortfall that occurs as their growth demands outstrip what maternal milk alone can supply, especially in systems where ewe milk production is itself limited by poor maternal nutrition.

To test this idea under realistic Ethiopian conditions, the research team designed a randomized complete block experiment involving 36 healthy 50% Dorper crossbred lambs (Dorper × Menz), born in the center’s sheep breeding flock. The animals were enrolled at approximately seven days of age and allocated to four treatments balanced for sex, dam parity, and birth weight. The control group (T1) followed routine center management: lambs suckled their dams and had access only to the 300-gram daily concentrate supplement offered to the ewes themselves. Treatment 2 (T2) added vetch hay to dam milk, offered at 10 percent of the starter-ration allowance. Treatment 3 (T3) received dam milk plus a locally formulated starter ration, while Treatment 4 (T4) combined both the starter ration and vetch hay. The starter ration was built from noug seed cake as the principal protein source, with yellow corn grain and wheat bran supplying energy, plus mineral and vitamin premixes. Formulated to National Research Council guidelines with 12.0 MJ of metabolizable energy and 18 percent crude protein per kilogram of dry matter, the mash diet targeted an average daily gain of 150 grams and was offered at 3.5 percent of each lamb’s body weight, with allowances recalculated weekly.

The results were striking. Initial body weight did not differ among treatments, confirming that the groups started on an equal footing, but from the fourth week onward the supplemented groups began pulling decisively ahead. By week ten, lambs on the starter ration weighed an average of 17.65 kilograms, and those on starter ration plus vetch hay 18.30 kilograms, compared with just 12.41 kilograms in the control group. At weaning at three months, average daily gain reached 185 grams per day on the starter ration and 196 grams per day on starter ration plus vetch hay, against only 106 grams per day in the control group. Final weaning weights told the same story: 18.20 and 18.70 kilograms for T3 and T4 respectively, versus 11.90 kilograms for controls, with the vetch-only group intermediate at 14.50 kilograms. Statistical analysis using linear mixed-effects models, which accounted for repeated measurements on the same animals and adjusted for initial body weight, confirmed significant effects of treatment, time, and their interaction on pre-weaning body weight, with p-values of 0.004 or lower.

Crucially, the growth advantage did not evaporate once supplementation ended. After weaning, body weights at 6, 9, and 12 months remained significantly higher in the supplemented groups, with treatment and time both highly significant effects, even though the treatment-by-time interaction was not, meaning the between-group differences were maintained rather than widening or closing. At 12 months, lambs from the starter ration groups weighed about 27.2 kilograms, compared with 21.45 kilograms in the control group, a difference of nearly 6 kilograms at the yearling stage. This carry-over effect is among the most commercially significant aspects of the trial, because it suggests that a relatively short period of early nutritional investment produces lasting structural gains in animal size rather than a transient growth spurt. The authors attribute this plausibly to enhanced rumen development, improved metabolic programming, and smoother adaptation to solid diets after weaning, while cautioning that feed intake, digestibility, and rumen morphology were not directly measured in the study.

Perhaps the most revealing analysis concerned the predictive power of early body weight. A regression of 12-month body weight on 3-month body weight produced a coefficient of determination of 0.780, meaning that roughly 78 percent of the variation in yearling weight could be explained by weight at weaning alone. Each additional kilogram gained by three months was associated with an estimated 1.09 kilograms of extra body weight at twelve months. Complementary correlation analysis reinforced the message: postnatal weights at 3, 6, and 12 months were strongly and positively correlated (r = 0.69–0.92), birth weight showed moderate positive correlations with later weights, and dam body weight and body condition score were also moderately associated with lamb growth. Parity, by contrast, was only weakly related to offspring growth. Together these findings argue that management aimed at the first three months of life, including maintaining ewes in good body condition, captures most of the leverage available for shaping an animal’s productive lifetime.

One nuance in the data deserves attention. Although lambs receiving vetch hay alongside the starter ration performed numerically best across nearly every measurement, the differences between T3 and T4 did not reach statistical significance, indicating that the starter ration alone was sufficient to drive the observed growth response under these conditions. This contrasts with earlier studies in which legume forages such as common vetch conferred measurable additional benefits on lamb growth and ruminal fermentation, and the authors suggest that when a concentrate supplement already meets the nutrient requirements of a growing lamb, additional forage supplementation may yield only marginal returns. They also note that supplement responses tend to diminish as lambs mature and their rumens become functionally developed, consistent with prior reports that early growth advantages from starter feeding can fade with age in some systems.

The trial was not without limitations, which the authors acknowledge candidly. Control lambs, in keeping with routine husbandry and animal welfare practice, had incidental access to small amounts of their dams’ concentrate, which may have narrowed the nutritional contrast between groups and made the true effect of supplementation an underestimate rather than an overestimate. Feed intake was recorded at the group rather than the individual level, so individual variation in consumption could not be quantified, and outcomes such as carcass traits, reproduction, welfare, and economics were outside the study’s scope. The correlation analyses describe associations rather than causal pathways, and the findings apply strictly to the on-station conditions of the experiment.

Even with those caveats, the practical implications for smallholder sheep producers are considerable. Every component of the starter ration, noug seed cake, maize grain, and wheat bran, is already part of the Ethiopian feed economy, and vetch (Vicia dasycarpa) grows well in the highlands without fertilizer inputs, meaning the intervention does not depend on imported or expensive inputs. Before widespread adoption, however, the researchers recommend multi-location and on-farm validation trials, longitudinal studies of long-term effects on adult productivity and carcass characteristics, investigation of nutrition-by-genotype interactions, and rigorous cost-benefit analysis. If those follow-up studies confirm what this trial suggests, a simple bucket of locally mixed starter feed, offered in the first weeks of life, could become one of the most cost-effective tools available for lifting lamb productivity, and rural incomes, across feed-limited farming systems in Ethiopia and beyond.

Subject of Research: Starter ration supplementation and its effect on pre- and post-weaning growth performance of Dorper × Menz lambs in Ethiopia

Article Title: Effect of starter ration supplementation on pre- and post-weaning growth performance of Dorper × Menz lambs

Article References: Nigat, L. A., Getachew, T., Alamerew, E. A., Eshete, M., Kebede, A., Besufikad, S., Abebe, A., Tesema, Z., Ayele, F., Yitagesu, E., Aydefruhim, D., Mekonen, T., & Bisrat, A. (2026). Effect of starter ration supplementation on pre- and post-weaning growth performance of Dorper × Menz lambs. Discover Animals, 3(1), Article 89. https://doi.org/10.1007/s44338-026-00248-1

Image Credits: AI Generated

DOI: 10.1007/s44338-026-00248-1

Keywords: lamb growth, starter ration, Ethiopia, Dorper, Menz sheep, weaning, average daily gain, vetch hay, smallholder farming, rumen development, animal nutrition, sheep production