Targeted selective supplementation for goat parasite control
Targeted selective supplementation with local plants cut anthelmintic use by 54 percent on Malawi goat smallholdings without hurting growth or kidding outcomes. Farmers scored each goat every two weeks with the Five Point Check and fed 250 g of Commiphora africana, Ficus ingens, or Gmelina arborea per day for five days only to borderline or sick animals. Sick goats still received albendazole, and the combination cleared parasites faster than the drug alone.
Why gastrointestinal nematodes hit smallholder goats so hard
Stomach and intestinal worms, known as gastrointestinal nematodes or GINs, are the largest parasitic drain on small ruminant production, and smallholder goat farming carries the worst of it. They do not just kill animals. They drain protein, suppress appetite, stunt kids, and push already thin goats into decline. The damage is worst where nutrition is worst, because a malnourished goat cannot mount an effective immune response against a burden it would otherwise tolerate.
For a smallholder family the arithmetic is brutal. Goats are the buffer against crop failure and the school fee fund. Losing one animal to worms can tip a household into food insecurity, and in regions where a single vet serves thousands of animals, there is often nobody to call before it is too late.
The standard answer, dosing the whole herd on a schedule, has two problems here. Anthelmintics cost money that smallholders do not have, and blanket dosing accelerates resistance by killing every susceptible worm and leaving only resistant ones to reproduce. Resistance is now widespread enough that the industry benchmark for a working treatment is a fecal egg count reduction (FEC) above 95 percent. Anything less selects for resistance.
A third problem is easy to miss. Tethering goats during the growing season to protect crops removes exactly the browse that would let animals self-medicate, so worm burden and feed gap peak together. Any control strategy that ignores the feed gap treats half the disease.
What targeted selective supplementation is
The method combines two ideas that are usually tested separately. The first is targeted selective treatment, or TST: instead of dosing the herd, you score each animal and intervene only where the score says intervention is needed. The second is nutraceutical feed supplementation, giving animals bioactive plants that support resilience rather than drugs that attack parasites directly.
In this trial the two were welded into one protocol. The Five Point Check, a low-resource scoring system, sorts every goat into healthy, borderline, or sick at each visit. Healthy animals get nothing. Borderline animals get plant material. Sick animals get plant material plus albendazole. The plant is the first-line intervention; the drug is the escalation.
That ordering matters. The botanical resource goes where it can change a trajectory, and the drug goes only where the trajectory has already failed. The hypothesis was simple: local plants carry nutraceutical value, and if you aim them precisely, goat health improves and drug use falls.
How the trial was run: farms, goats, and the Five Point Check
The trial ran across four smallholder villages in central Malawi, in a wet tropical climate averaging 20.7 degrees Celsius with 1000 to 1500 mm of annual rainfall. Forty-three smallholders kept 197 adult indigenous-breed goats, 194 of them female, all over one year old. Two villages were assigned to the control group and two to the plant group, so neighboring farmers were not running two different protocols side by side.
Table 1. Trial design.
| Element | Control-TST group | Plant-TST group |
| Goats | 101 | 96 |
| Villages | 2 | 2 |
| Monitoring | Five Point Check about every two weeks | Same |
| Sick goats | Albendazole, 10 mg per kg body weight, oral | Albendazole plus 250 g per day of plant material for at least 5 days |
| Borderline goats | Normal feeding | 250 g per day of plant material for at least 5 days |
| Healthy goats | Nothing | Nothing |
| Fecal sampling | McMaster egg counts, factor 50 | Same |
The Five Point Check scores five signs: nasal discharge, eye mucous membrane color (the FAMACHA score, where higher means paler and more anemic), body condition score, submandibular edema (bottle jaw), and dag score (fecal staining from scour). The decision chart was simple. A goat was sick with any of FAMACHA 4 or worse, Dag score 4 or worse, body condition score 1 or worse, or jaw score 1. A goat was borderline with FAMACHA 3, Dag score 3, or body condition score 1.5. Anything else was healthy.
Researchers and local veterinary assistants trained the farmers to run the checks themselves. Over the study period the team completed 3050 checks and analyzed 2625 fecal samples. The scoring was not decoration. FAMACHA and body condition score were present in 98.9 percent of sick-goat scores and 86.8 percent of borderline scores, while scour showed up in only 18.4 percent of sick goats. The two cheapest, least invasive checks were doing the diagnostic work.
Which plants went into the supplement and why
Three species made the cut: Commiphora africana (African myrrh), Ficus ingens (red-leaved fig), and Gmelina arborea (beechwood). The ethnoveterinary selection criteria were deliberately unglamorous. The plants had to be already used by local farmers, easy to identify, available year round, big enough to harvest from without damage, non-toxic, and nutritionally sound. All three carry crude protein above 15 percent, and all three have published in vitro anthelmintic activity against Haemonchus contortus or related nematodes, so they qualified as bioactive rather than merely edible.
Each participating farmer was assigned one specific tree per species for the whole study, which kept the botanical resource traceable and prevented over-harvesting of any single tree. The supplement was weighed once in a plastic container so farmers could estimate portions without scales, and the dose was about 250 g fresh material per goat per day for at least five consecutive days after each check.
What happened to anthelmintic use
Over the whole study, goats in the plant-TST group needed anthelmintic intervention on 2.18 percent of all checks, against 3.99 percent in the control group (chi-square 7.68, p = 0.005). The paper reports that as a 54 percent reduction in anthelmintic need. Put the other way round: 74 percent of plant-TST goats never needed a drug at all, against 66 percent in the control group.
Table 2. Headline outcomes under the two regimes.
| Outcome | Control-TST | Plant-TST |
| Anthelmintic interventions, share of all checks | 3.99 percent | 2.18 percent |
| Goats never needing a drug | 66 percent | 74 percent |
| Median FEC before drug (EPG) | 200 | 275 |
| Median FEC two weeks after drug (EPG) | 0 | 0 |
| Mean FEC at drug treatment (EPG) | 1178 | 3010 |
| Mean FEC two weeks after (EPG) | 168 | 85 |
| Mean FEC reduction | 85.7 percent | 97.2 percent |
| Goats reaching over 95 percent FEC reduction | 23 of 38 | 16 of 18 |
| Borderline goats failing to improve | 29.55 percent | 7.24 percent |
| Visits classified marginally healthy (median) | 86.93 percent | 90.45 percent |
Note where the saving came from. It was not withholding drugs from sick animals. It was fewer animals becoming sick in the first place, which is what a feed-gap intervention is supposed to do.
Parasite clearance after treatment
When drugs were needed, they worked, and they worked better in the plant group. Median FEC fell to zero in both groups two weeks after treatment, but the group-level numbers tell a finer story. Plant-TST goats entered treatment with a mean of 3010 EPG and left at 85 EPG, a 97.2 percent reduction. Control-TST goats went from 1178 to 168 EPG, an 85.7 percent reduction.
The plant-TST goats entered treatment with higher egg counts, so the comparison is not a free win. But restricted to goats that actually had eggs at treatment, the reduction was 94.8 percent (SD 17.2) under plant-TST against 84.0 percent (SD 28.3) under control-TST (one-tailed t = 1.748, p = 0.043). And the benchmark that matters for resistance: a reduction above 95 percent was reached in 16 of 18 plant-TST goats versus 23 of 38 control-TST goats (chi-square 4.933, p = 0.026).
The practical consequence was continuity of care. Under control-TST, failed clearance meant some goats needed repeat doses, including consecutive treatments. Under plant-TST, every goat improved after its first treatment, so no consecutive drug courses were needed at all.
What happened to borderline goats
The mechanism of the whole approach lives in the borderline window, and this is where the data are most interesting. Under plant-TST, supplemented borderline goats improved 47.37 percent of the time and stabilized 45.39 percent of the time. Only 7.24 percent worsened into the sick category, and 46.15 percent of those snapped straight back to healthy. Under control-TST, where borderline animals received nothing beyond normal feeding, 29.55 percent failed to improve (chi-square 7.581, p = 0.005).
The plant supplement was not a weak drug substitute. It was a guardrail. It caught animals sliding toward disease and pulled most of them back, and when it failed, recovery after the drug was faster and cleaner.
Seasonal pressure and when interventions were needed
Parasite pressure in this climate is violently seasonal. Mean FEC climbed from 292 EPG in May 2020 to a peak of 2672 EPG in February 2020, then collapsed to 64 EPG by August. The rainy season, November to April, is when worms build up and when tethered goats lose the most weight. The dry season is when the herd looks healthy, with 90 to 98 percent of goats at FAMACHA 1 or 2 from May to October.
Table 3. Monthly operations (rows recovered from the source table).
| Month | Rainfall mm | Mean FEC EPG | Control checks | Control drug % | Plant checks | Plant drug % | Supplemented % |
| Jan | 10.3 | 1926 | 21 | 19.0 | 22 | 9.1 | 45.5 |
| Feb | 7.5 | 2672 | 101 | 4.0 | 96 | 8.3 | 52.1 |
| Mar | 1.2 | 1795 | 146 | 8.2 | 104 | 4.8 | 38.5 |
| Apr | 0.2 | 1128 | 99 | 2.0 | 134 | 0.7 | 11.2 |
| May | 0.3 | 281 | 93 | 0.0 | 104 | 0.0 | 6.7 |
| Jun | 0.0 | 158 | 91 | 1.1 | 74 | 1.4 | 4.1 |
| Jul | 0.0 | 124 | 118 | 1.7 | 112 | 1.8 | 6.3 |
| Aug | 0.0 | 64 | 112 | 1.8 | 92 | 0.0 | 2.2 |
| Sep | 0.0 | 103 | 150 | 2.7 | 105 | 1.0 | 4.8 |
| Oct | 0.8 | 219 | 110 | 1.8 | 124 | 0.8 | 4.0 |
Two things stand out. Interventions were needed in both seasons, so a dry-season holiday from monitoring is not safe. And supplementation demand peaked with the rains, which is also when the plants are most available. The later months of the source table were truncated in extraction and are not reproduced here.
How much plant material targeted selective supplementation actually needs
The obvious objection to plant supplementation is that it sounds resource-hungry. The trial measured it, and targeted use is remarkably cheap in biomass.
Only 199 of 1471 checks (13.5 percent) ended in supplementation, and 167 of those (83.9 percent) went to borderline rather than sick goats. Across the whole study, 58.3 percent of goats were supplemented at least once, averaging 2.9 visits out of 17.6 (16.9 percent). Total harvest was 248.8 kg over 399 days from 23 farms: 2.7 kg per supplemented goat, 27.1 g per smallholder per day, and just 6.8 g per goat per day averaged across the herd.
Table 4. Plant harvest by species.
| Species | Checks | Supplementation events | Goats | Harvest kg | kg per goat | g per goat per day |
| Commiphora africana | 363 | 77 | 18 | 96.3 | 5.3 | 14.0 |
| Ficus ingens | 927 | 89 | 63 | 111.3 | 1.8 | 4.4 |
| Gmelina arborea | 400 | 33 | 15 | 41.3 | 2.8 | 6.9 |
| Total | 1471 | 199 | 96 | 248.8 | 2.6 | 6.8 |
Compare that with the alternatives. Supplementing every goat for the whole study would have required 9576 kg, a 3850 percent increase. Periodic whole-group treatment would have required 3420 kg, a 1374 percent increase. Even restricting whole-group supplementation to the rainy season alone would have required 1851 kg, a 744 percent increase. Measured against those baselines, targeted selective supplementation cut plant harvesting by 97.4 percent, 92.7 percent, and 86.6 percent respectively.
Commiphora africana was drawn on significantly more than the other two species (chi-square 40.121, p below 0.001) and also had the most favorable nutritional profile. But it did not perform best on the outcome that matters for drug deferral. Kaplan-Meier curves for time to first drug treatment showed that goats fed Ficus ingens had an 87 percent probability of remaining treatment-free at 225 days, against 74 percent for Commiphora africana and 59 percent for Gmelina arborea (p = 0.039). Ficus ingens is the lowest-protein of the three and the highest in fiber, so its edge probably comes from plant secondary metabolites rather than nutrition, and it is most available during the rains when worm pressure peaks.
The counterintuitive findings
Four results from this trial run against the obvious expectations, and each one is worth stating plainly.
The plants did not kill the worms. Supplementation on its own produced no detectable drop in FEC, and it did not significantly delay the first need for a drug in the overall Kaplan-Meier analysis. Anyone selling these plants as a dewormer is misreading the data. The benefit ran through the host: extra crude protein replacing worm-driven protein loss, more amino acids for the immune response, better body condition, and better resilience to infection.
The synergy was real but conditional. Goats that received plant material before the drug cleared it better afterward. That pattern echoes in vitro work showing plant secondary metabolites can enhance synthetic anthelmintic efficacy. But the literature also contains the opposite case, where a bioactive forage reduced parasite clearance when paired with a different drug. Plant-drug combinations have to be tested, not assumed.
Healthy goats carried heavy infections. The average FEC among goats classified healthy was 453 EPG, and it rose with the rains. A low egg count can be clinically serious in a malnourished goat, while a high count can be harmless in a robust one. This is why egg-count thresholds fail as treatment triggers: pooled thresholds of 500, 1000, or 2000 EPG would have increased drug use by 189 to 804 percent, given 92.2 to 92.6 percent of doses to non-sick goats, and still missed 37.6 to 85.9 percent of the animals that actually got sick.
Precision beat every bulk strategy by a wide margin. At any single time point, whole-group treatment wastes 86 to 100 percent of doses on animals that do not need them, averaging 94.9 percent. A single annual whole-herd treatment would, at best, have treated 21.9 percent of the goats that fell sick that year. Monitoring plus targeted intervention beat all of these on drug use, botanical use, and accuracy simultaneously.
Practical recommendations for smallholders
- Score every goat on a fixed cycle, roughly every two weeks. The Five Point Check takes minutes per animal and needs no equipment beyond a color chart and a hand.
- Treat the borderline window as the intervention point. Feeding only when an animal is already sick wastes the cheapest, most effective moment to change its trajectory.
- Budget about 250 g of fresh plant material per goat per day for at least five days. Herd-wide, targeted use averaged 6.8 g per goat per day and 27.1 g per household per day, which is trivial biomass.
- Assign each household one identified tree per species. This prevents over-harvesting, keeps quality consistent, and makes the practice auditable.
- Keep the drug as escalation, not routine. Sick animals still got albendazole at 10 mg per kg, and every plant-TST goat recovered after one course.
- Prepare for the rainy season. Worm burden and feed gap peak together; stockpiling forage or identifying wet-season trees before the rains is cheaper than rescue treatment.
- Do not treat on egg counts alone in this setting. Healthy animals can run high FECs during the rains, and thin animals can be in trouble at low counts.
Limitations
The trial had no untreated control group, for ethical reasons: withholding both monitoring and intervention from food-insecure households was not defensible. Individual feed intake and movement could not be tracked, so dietary effects outside the supplement are mixed into the results. The study ran just over a year, so nothing is known about whether farmers sustained the practice after the researchers left. Some monthly rows of the source operations table were truncated in extraction and are reported only where recovered. Mortality was similar in both groups (12.5 percent plant-TST, 10.9 percent control), and because necropsies were not possible most deaths could not be attributed; predation and ingested plastic pollution are both documented local causes, and in the plant group most deaths occurred in goats scored healthy beforehand, which suggests they were not worm- or nutrition-driven.
Bottom line
Targeted selective supplementation turned local browse into a precision tool. Scoring goats with the Five Point Check and feeding borderline animals 250 g a day of Commiphora africana, Ficus ingens, or Gmelina arborea cut anthelmintic interventions by 54 percent, raised parasite clearance after treatment above the 95 percent resistance benchmark, eliminated repeat drug courses, and did it all on 248.8 kg of plant material instead of the 9576 kg that blanket feeding would have cost. The plants did not deworm the goats. They made the goats, and the drug, work better.
FAQ
What is targeted selective supplementation?
Targeted selective supplementation is a parasite control method that feeds bioactive local plants only to the animals that need support. Farmers score each goat with the Five Point Check, then give about 250 g of plant material per day for five days to goats classed borderline or sick. Healthy animals receive nothing, so most of the herd is never intervened on.
How much did targeted selective supplementation reduce anthelmintic use in goats?
In the Malawi trial, goats in the supplemented group needed drugs on 2.18 percent of all monitoring checks against 3.99 percent in the control group, a 54 percent reduction in anthelmintic need. Seventy-four percent of supplemented goats never needed a drug at all, against 66 percent of controls. The saving came from fewer animals becoming sick, not from withholding treatment.
Which plants were used for targeted selective supplementation?
Three species qualified: Commiphora africana, Ficus ingens, and Gmelina arborea. They were chosen for year-round availability, easy identification, existing local use, crude protein above 15 percent, and published in vitro activity against Haemonchus contortus. Farmers harvested from one assigned tree per species, about 250 g fresh material per goat per day for at least five days.
Did the local plants lower fecal egg counts on their own?
No. Supplementation alone produced no detectable reduction in FEC and did not significantly delay the first need for treatment. The benefit ran through host resilience: extra protein offsetting worm-driven protein loss and supporting the immune response. What the plants did improve was the goat’s response to the drug, with FEC reductions of 94.8 percent against 84.0 percent in controls.
What is the Five Point Check and how does it guide treatment?
The Five Point Check scores five signs in each goat: nasal discharge, FAMACHA eye color, body condition score, bottle jaw, and dag score. A goat is sick at FAMACHA 4 or worse, Dag 4 or worse, body condition score 1, or jaw score 1, and receives albendazole. Borderline animals, at FAMACHA 3, Dag 3, or body condition score 1.5, receive plant supplementation instead.
How much plant material does targeted selective supplementation need?
Targeted use averaged 6.8 g per goat per day and 27.1 g per smallholder per day, totaling 248.8 kg over 399 days from 23 farms, about 2.7 kg per supplemented goat. Supplementation happened on only 13.5 percent of checks, mostly for borderline goats. Feeding every goat would have needed 9576 kg, a 3850 percent increase, which is the case the targeting avoids.
Can targeted selective supplementation replace anthelmintics entirely?
No. In this trial every sick goat still received albendazole at 10 mg per kg body weight, and plant supplementation was added to the drug rather than substituted for it. The role of the plants was to keep animals out of the sick category and to improve drug clearance once treatment was needed. No plant-only arm achieved a measurable FEC reduction.
Why is targeted selective treatment better than whole-herd dosing?
Whole-group treatment wastes 86 to 100 percent of doses on animals that do not need them, averaging 94.9 percent, and one annual treatment would at best cover 21.9 percent of goats that fall sick that year. Pooled egg-count thresholds would raise drug use by 189 to 804 percent and still miss 37.6 to 85.9 percent of sick animals. Targeted dosing beats all of these at once.
Did targeted selective supplementation affect kid birth weight and growth?
No significant differences were found. Kid birth weight averaged 2.93 kg in the supplemented group against 2.96 kg in controls, and daily gain from birth to the end of the study was 54 g against 52 g. Both figures were already higher than previously reported local averages, but the supplement itself delivered no measurable reproductive or growth bonus at the aggregate level.
Does targeted selective supplementation protect against anthelmintic resistance?
It helps on two fronts. Because healthy animals are never dosed, susceptible worms survive in refugia and dilute resistance genes in the population. And because supplemented goats cleared the drug better, 16 of 18 reached the 95 percent FEC reduction benchmark against 23 of 38 controls, leaving fewer survivors of a sub-lethal treatment to rebuild the population.
Which plant species worked best for delaying the first drug treatment?
Ficus ingens performed best on time to first treatment, with an 87 percent probability of remaining drug-free at 225 days against 74 percent for Commiphora africana and 59 percent for Gmelina arborea. Commiphora africana was used most often and had the best nutritional profile, yet Ficus ingens is lowest in protein and highest in fiber, so its edge likely comes from plant secondary metabolites.
What are the limitations of targeted selective supplementation?
The trial had no untreated control group, feed intake could not be tracked, and it ran just over a year with no follow-up. Mortality was similar in both groups and mostly unattributable, with predation and ingested plastic pollution documented locally. The approach also depends on farmers being able to score animals reliably and on the chosen plants being locally available.
