A new study out of Ekiti State University in Ado-Ekiti has delivered some of the most detailed physiological data yet recorded for West African Dwarf sheep fed Gmelina arborea leaf meal, and the findings carry a clear message for Nigerian livestock farmers: Gmelina arborea leaves and cassava peels offer promising, low-cost feed resources for sheep in the tropics, particularly during forage scarcity. Gmelina provides protein and minerals, while cassava peels supply fermentable energy. When properly dried, ensiled, and balanced with other nutrients, they can improve sheep health and productivity, leading to sustainable small ruminant production.

The research, published this year in the Agriculture and Biology Journal of North America, was led by Ms Olayinka Tawose of the Department of Animal Production and Health Sciences at Ekiti State University. Ms Tawose obtained and used twenty-four West African Dwarf rams in a twelve-week feeding trial designed to measure not just voluntary intake or digestibility, but the deeper physiological responses that feed quality ultimately affects: respiratory rate, pulse rate, rectal temperature, packed cell volume, red blood cell count, haemoglobin concentration, and a full panel of haematological indices.

Ms Tawose occupies a distinctive position in the field of animal science in Nigeria. Few researchers in the country have applied a full haematological and physiological assessment framework to the question of browse plant supplementation in West African Dwarf sheep under controlled management conditions, and none have done so for Gmelina arborea at the level of granularity this study achieves. The investigation fills a critical gap: while the nutritional composition of Gmelina arborea leaves has been noted in Nigerian literature, the internal biological response of sheep to its sustained dietary inclusion, measured through packed cell volume, haemoglobin concentration, red and white blood cell counts, and a full differential of corpuscular indices, had never before been documented with this precision. The work is, according to peers in the field, a first of its kind.

“Feed intake and digestibility data tell you a lot, but they do not tell you everything,” Ms Tawose said. “We needed to assess the internal environment of the animal, using the blood parameters, respiratory, temperature, and pulse rates, to confirm that what we were seeing on the outside was matched by genuine physiological health on the inside.” Four dietary groups were tested, with cassava peels replaced by Gmelina arborea leaf meal at 0, 33.33, 66.67, and 100% of a 16 percent crude protein concentrate ration. The trial also compared two management systems, intensive housing and semi-intensive housing, to assess how the feeding environment interacts with diet to shape the experimental animals’ health outcomes.

The physiological measurements were reassuring across all dietary groups, but the patterns within them were highlighted. Animals in the 33.33% Gmelina arborea group under intensive management recorded a mean respiratory rate of 23.20 respirations per minute, against 25.70 per minute observed in the unsupplemented control. Pulse rates followed the same trend in every supplemented group. Rectal temperatures held steady between 39.00 and 39.80 degrees Celsius across all treatments, well within the normal clinical range for sheep, ruling out thermal stress as a factor in the observed differences.” The physiological values were all within the accepted normal range for sheep, but the direction was clear,” Ms Tawose said. “Every indicator pointed in favour of the Gmelina-supplemented groups.”

The haematological findings were the centrepiece of the study. Packed cell volume, a frontline indicator of nutritional adequacy and resistance to anemia, reached 34% in the 33.33% Gmelina arborea group under an intensive management system, against the 28% observed in the control group. Red blood cell counts were also higher in the supplemented groups. Haemoglobin concentration, which determines how much oxygen the blood can carry and ultimately governs the animal’s stamina and productive capacity, stood at 11.04gm/100mm-1 in the supplemented group against just 7.03 gm/100mm-1 in the control. All values fell within published normal ranges for healthy sheep. “When your packed cell volume and haemoglobin are that much higher in the supplemented group, you are looking at animals with significantly better oxygen-carrying capacity and better nutritional status,” Ms Tawose said. “That translates directly into productivity and resilience.”

The management system data added a further dimension to the findings. Intensively managed animals recorded superior haematological values across nearly every parameter compared to their semi-intensively managed counterparts, a pattern Ms Tawose attributed to the energy cost of movement outside the pen and the more controlled feed delivery available under intensive housing. “Animals under the semi-intensive system were expending energy on physical activity that did not contribute to production,” she said. “The blood data reflected that difference clearly.” The finding is a practical reminder that housing quality and feeding discipline are not secondary considerations. They shape the health outcome that even a well-designed diet can deliver.

For Audu Innocent Ogbeh, Nigeria’s serving Minister of Agriculture and Rural Development and a farmer himself with a grounded understanding of what livestock productivity means to rural incomes, the data assembled by Ms Tawose represents more than a scientific milestone. “What researchers like Ms Tawose are doing is proving, with data that cannot be questioned, that Nigeria has the resources to feed its livestock well without expensive imports,” Mr Ogbeh said. “Healthy blood counts, better oxygen-carrying capacity, stronger animals. That means better yields, better incomes for farmers, and more protein on Nigerian tables. This country gains enormously when we invest in research that turns our natural resources into productive assets.”

Mean corpuscular haemoglobin concentration reached 32.47% in the 33.33% inclusion group against 25.11% in the control under intensive management. White blood cell counts were highest in the control group and lowest in the supplemented animals, a result Ms Tawose reads as a marker of efficient immune function in better-nourished animals rather than any sign of suppression. Neutrophil and monocyte values across all supplemented groups fell within the established normal range for healthy sheep throughout the twelve-week trial.

Ms Tawose’s recommendation from this study is unequivocal: 33.33 % Gmelina arborea leaf meal in the concentrate ration delivers the strongest combination of physiological stability and haematological health in West African Dwarf sheep. “The science on Gmelina arborea is now clear,” she said. “It is a high-quality, low-cost, safe, and accessible feed resource that Nigerian farmers can incorporate into their ruminant diets with confidence, and the blood work proves the animals are thriving on it.”