A simple science-based approach to meet feed scarcity during droughts

By Genene Regassa, Dr Abay Bekele, Jatani Hana, Abnet Sisay, Dida Kalicha, Emmanuel Boru Elema, Abubeker Tussa and Harinder P. S. Makkar

Dry-season feed scarcity is one of the leading causes of livestock mortality and productivity decline in pastoral regions of Ethiopia. During droughts across Africa, when pastures dry up and conventional forages disappear, the only remaining green biomass often comes from browse species: trees and shrubs. However, livestock rarely consume these resources. Although browse biomass is abundant in rangelands, its high tannin content limits voluntary intake and nutrient utilisation in sheep and cattle.

Browse-aid (polyethylene glycol, PEG-4000) binds and inactivates tannins, thereby improving the intake and digestibility of browse species. It is safe, inert, and widely used in pharmaceuticals and cosmetics. Research trials have demonstrated that supplementation with PEG enhances browse consumption and digestion. This intervention represents a practical “Lab to Land” approach to addressing dry-season feed shortages.

Under the United States Government Foreign Assistance-funded DERR-BOASS emergency and recovery programme, VSF-Germany implemented a large-scale distribution and field application of Browse-aid in Afar, Oromia (Borana), and Southern Ethiopia. The objective was to protect drought-vulnerable sheep and cattle by improving browse intake, health status and body condition during periods of feed scarcity. The approach is analogous to administering a lactase tablet to lactose-intolerant individuals before consuming milk and milk products.

The study

The scale-out intervention was conducted in Guchi and Miyo woredas of the Borana Zone, Oromia Region, Ethiopia (see Map). The supplementation period lasted 60 days, coinciding with an extreme scarcity of natural pasture on the rangelands.

Oromia Region (Borana) study sites, representing Erder and Gofa Seden Kebele in Guchi Woreda and Dibandida Kebele in Miyo Woreda, 
Oromia Regional State

Map elaborated by Abnet Sisay 

Target animals and sampling:

• Sheep: 250 animals (5 per household)
• Cattle: 150 animals (3 per household)

The Browse-aid was given to the above stated number of animals. Since routine body weight measurements and qualitative data collection were labour-intensive, approximately 33 per cent of the experimental animals (79 sheep [31.6 %] and 53 cattle [35.3 %]) were randomly selected, marked and used as sentinel animals for repeated measurements at Day 0, Day 30, and Day 60. In addition, a comparison group of non-Browse-aid-supplemented animals grazing in the same rangelands (50 sheep and 52 cattle) was monitored.

Supplement preparation and administration:

Browse-aid was manually mixed with 50 g of wheat bran (WB) and fed individually to animals as follows:

• Sheep: 5 g Browse-aid mixed with WB
• Cattle: 15 g Browse-aid mixed with WB

Daily doses were pre-measured using standardised cups and administered once a day, before the animals went out in the rangelands.

Quantitative parameters observed:

• Body Weight (BW):
  • Sheep were weighed using digital scales.
  • Cattle body weight was estimated using a heart-girth tape.

Qualitative indicators observed:

• Hair coat appearance: Coarse (0), Shiny (1), Very shiny (2); scores given are presented in parentheses.
• Eye shine: Pink/dull (0), Shiny (1), Very shiny (2); scores given are presented in parentheses.
• Foraging frequency: Visual assessment of browsing activity
• Body Condition Score (BCS): 1–5 scale for both sheep and cattle

Impact achieved

Following the incorporation of Browse-aid, changes in body weight of sheep and cattle were recorded. Sheep exhibited an average body weight gain of approximately 10 per cent, while cattle achieved a 6 per cent increase in body weight over the 60-day supplementation period (see Table below).

Body weight (BW) changes after 30 and 60 days of supplementing Browse-aid

These observations demonstrate the potential of Browse-aid not only to prevent livestock losses due to feed shortages but also to promote body weight gain.

The results of hair coat appearance and eye shine assessments were as follows:

Changes in hair coat texture and eye shine scores following Browse-aid supplementation*

* Subjective assessments of hair coat and eye appearance were converted into numerical scores following the procedures described in the Materials and Methods section of the referenced study: https://www.cabidigitallibrary.org/doi/full/10.1186/s43170-024-00287-2 

Browse-aid-Supplemented Group.In sheep, scores for hair coat appearance at Day 0, Day 30, and Day 60 were 79, 88, and 85, respectively, while scores for eye shine were 79, 79 and 93 over the same observation periods.

In cattle, hair coat appearance scores at Day 0, Day 30, and Day 60 were 50, 49, and 56, respectively. Corresponding eye shine scores were 25, 50 and 50 at Day 0, Day 30 and Day 60, respectively.

Non-Browse-aid Group.Among sheep in the non-supplemented group, 37 animals (51 %) exhibited a coarse hair coat, while the remaining animals maintained a shiny hair coat appearance. A large number of sheep (94 %) displayed dull eye appearance.

For cattle, 28 animals (53 %) had a coarse hair coat, and 98 per cent showed dull eye appearance.

As can be seen, Browse-aid supplementation clearly improved hair coat texture and eye shine – recognised proxies for nutritional and metabolic status, indicating enhanced animal welfare and overall nutritional condition.

Browsing activity increased from approximately Day 10 and stabilised by Day 30 in both sheep and cattle, indicating an enhanced willingness to utilise shrub vegetation (also see Photo).

An enhanced willingness to utilise shrub vegetation could be observed among the animals.
Photo: Andinet Adamau

The improvements in Body Condition Score are presented in the Table below. They were consistent with observed qualitative welfare indicators and reflected an overall enhancement in nutritional status.

Average Body Condition Score BCS after 60 days duration

Promising results

Browse-aid supplementation substantially enhanced body weight gains, shrub utilisation, animal welfare and nutritional status. Both sheep and cattle responded consistently across all measured parameters, and these improvements were accompanied by increases in body weight. The low daily dosages required (5 g for sheep and 15 g for cattle) make the approach highly scalable and suitable for sustaining long-term benefits under harsh, feed-limited conditions.

These findings are consistent with earlier field assessments conducted in Dassenech District (formerly part of the SNNP Region, now within the South Ethiopia Region) and Gode Woreda of the Somali Region, confirming the robustness of the approach across diverse ecological zones and rangelands with differing browse species composition.

The strong qualitative improvements observed, particularly in hair coat condition, eye shine and foraging behaviour, validate the role of Browse-aid in overcoming the non-consumption of tannin-rich browse species. Tannins are known to suppress feed intake and contribute to digestive inefficiencies and metabolic stress. By mitigating these effects, Browse-aid reduces vulnerability to drought-associated livestock diseases, improves health and reproductive performance, and enhances the overall resilience of pastoral herds.

Considerable interest among livestock owners

After observing the improved body condition and overall performance of the animals supplemented with Browse-aid, many farmers in the surrounding areas expressed strong interest in participating in the study. However, due to logistical and resource limitations, it was not possible to include all interested households. The farmers who were able to participate reported high levels of satisfaction with the intervention and expressed their appreciation and gratitude to the project and the project team members for introducing a technology that had the potential to significantly improve livestock survival and productivity, particularly during periods of feed scarcity and drought.

Following the study, beneficiaries (farmers and pastoralists) were keen to purchase Browse-aid, recognising that investing in the product would help save livestock that are otherwise at high risk of mortality during peak drought periods. For example, during the 2022 drought in East Africa, an estimated 3.3 million livestock died in the Borana area alone (the current study area), of which approximately 85 per cent were cattle. One key priority for government institutions and NGOs should therefore be to facilitate the availability Browse-aid in local markets.

A viable and climate-resilient feeding strategy

Browse-aid represents a viable and climate-resilient feeding strategy for Ethiopian pastoral systems, with broader relevance for drought-prone regions across Africa. It offers a substantial cost advantage over conventional emergency feeding. It is approximately 60 per cent cheaper for sheep and up to 90 per cent cheaper for cattle compared with transporting hay or concentrate feeds to drought-affected areas. Currently, Browse-aid is imported in Ethiopia; establishing a commercial Browse-aid supply chain within Africa would further reduce costs and enhance affordability.

It is recommended that the Browse-aid approach be scaled up across pastoral areas to reduce livestock health and welfare risks associated with long-distance trekking for water and feed during drought periods. Policy-makers and donors are encouraged to support institutional adoption and cross-regional rollout of this strategy. Investing in “standing feed, not trucked feed” represents a more sustainable and cost-effective use of drought-response funding.

Genene Regassa is a Veterinarian and Country Director at VSF-Germany, and is based in Addis Ababa, Ethiopia. He holds a Master’s degree in participation, development and social change from the University of Sussex, UK.

Abay Bekele is a Veterinarian and Program and Protection Advisor at VSF-Germany, and is based in Addis Ababa, Ethiopia.

Jatani Hana is a Project Manager at the VSF-Germany Borana Field Office, and is based in Yabello. He holds a Master’s degree in Project Management from Adama Science and Technology University, Ethiopia.

Abnet Sisay is a Country Program Manager at VSF-Germany, Addis Ababa, Ethiopia. He holds a Master’s degree in Development from Mekelle University, Ethiopia.

Dida Kalicha is a Project Officer at VSF-Germany, and is based in Guchi, Ethiopia.

Emmanuel Boru Elema is a Project Officer at VSF-Germany, and is based in Miyo, Ethiopia.

Abubeker Tussa is a MEAL Officer at VSF-Germany, and is based in Addis Ababa, Ethiopia.

Harinder P. S. Makkar is an International Consultant and holds PhD degree from the University of Nottingham, UK, and Dr. Habil from the University of Hohenheim, Germany.

Contact: hpsmakkar(at)outlook.com

More information:

Videos of Browse-aid fed animals are available on LinkedIn

Further reading:

Rural 21 no 2/24 issue on "Livestock"