A carefully formulated starter ration made from ingredients that Ethiopian smallholder farmers can already obtain locally has been shown to dramatically improve the growth of crossbred lambs, both before and after weaning, according to a new on-station trial conducted in the Ethiopian highlands. The study, carried out by researchers at the Debre-Birhan Agricultural Research Center under the Amhara Agricultural Research Institute, found that lambs given a nutrient-dense starter feed grew nearly twice as fast before weaning as lambs managed under conventional practice, and that this early advantage persisted all the way to one year of age. The findings, published in the open-access journal Discover Animals, offer a deceptively simple intervention for one of the most stubborn productivity problems in resource-limited sheep farming.
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
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Drew Townsend. (September 21, 2026). Simple Starter Feed Boosts Lamb Growth Before and After Weaning. Scienmag. https://scienmag.com/simple-starter-feed-boosts-lamb-growth-before-and-after-weaning/
Drew Townsend. “Simple Starter Feed Boosts Lamb Growth Before and After Weaning.” Scienmag, 21 September 2026, https://scienmag.com/simple-starter-feed-boosts-lamb-growth-before-and-after-weaning/. Accessed 21 September 2026.
Drew Townsend. “Simple Starter Feed Boosts Lamb Growth Before and After Weaning.” Scienmag. September 21, 2026. https://scienmag.com/simple-starter-feed-boosts-lamb-growth-before-and-after-weaning/
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Tags: animal nutritionaverage daily gainDorperEthiopialamb growthMenz sheeprumen developmentsheep productionsmallholder farmingstarter rationvetch hayweaning
