Minimizing parasitic infestation in ruminants during wet season

In the Philippines, the rainy season, especially during La Niña, is a critical period for grazing animals. This is the time when livestock grazed in pasture experience problems of poor nutrition, respiratory diseases, and gastrointestinal parasites commonly known as worms.

Parasitism brings enormous losses to the farm and causes anemia, decreased resistance to infections, poor breeding efficiency, reduced production of meat and milk, and weight loss, all of which can lead to death when left untreated.

To alleviate the ill effects of parasitism, farmers need to institute an integrated farm management approach. However, they need to understand first the cycle of infection, which begins when parasite-infested animals excrete manure with worm eggs. These eggs mature into effective larvae in the pasture. The larvae travel to the blades of grasses and shrubs, usually early in the morning when blades are moist. Then, these mature into full-grown worms in the stomach of grazing animals that ingested them.

Fig. 1. Confined goats stall-fed with forages during the wet season.

Farmers are advised to be conscious of the grazing time and avoid grazing during rainy days. They can totally confine their animals in pens during the entire wet season (Fig. 1) and practice rotational grazing when weather becomes favorable.

This practice is applicable in all regions of the Philippines. Adoption of this technology can help avoid or minimize parasitism and eventual death and increase farm productivity.

Requirements for adoption

– Appropriate pen or shelters with good ventilation
– Adequate clean forages for stall-feeding
– Dewormer (chemical and herbal)
– Water
– Different forages with deworming properties
– Type of parasite and parasitic load


Herd management

Provide pens or stalls appropriate to the type of animal, and ensure that pens, feeders, and water buckets are cleaned daily. Maintaining hygiene will reduce vulnerable stages of the parasitic cycle inside the barn.

Install covers on walls during inclement weather.

For the small ruminant pens, use slatted flooring for more convenient cleaning and install manure catchers underneath. For large ruminants, provide cemented floors that are sloped for easy cleaning.

Every day, provide balanced nutrition that includes energy feeds, forage, minerals, protein, salt, and plenty of clean water. Practice cut-and-carry system of feeding and gather forages from clean pastures, ungrazed by other animals.

Trim hooves as needed to prevent foot rot.

Quarantine newly-purchased stocks for a month before introduction to the herd.

With the help of a licensed veterinarian, implement a vaccination program against
diseases that may be a problem in the locality.

Keep individual animal records, and pay particular attention to kidding and calving dates. To avoid neonatal mortalities, provide boxes and beddings for the newborn, particularly during the cold, wet months.

Closely monitor the health status of the animals through daily inspection. Identify and isolate sick animals, and seek the advice of a licensed veterinarian. Subject the herd to the required tests appropriate in the locality as recommended by local government units. Provide supportive therapy for sick animals, especially those with diarrhea, hypoglycemia, and pneumonia.

Pasture management

To avoid ingestion of larvae-laden grass, avoid grazing the animals during the early hours of the morning when the sun has not yet dried the dew on the grass blades.

Practice rapid rotational grazing to rest parts of the pasture and break the parasitic cycle. To implement rapid rotational grazing, divide the pasture areas into at least 10 paddocks where mature animals are allowed to graze for 3-3.5 days/paddock before being moved to the next paddock. Return to the first paddock after a month, which is a schedule based on the premise that larvae become infective 4-7 days after being transmitted in feces.

Strategic deworming

Strategic deworming involved application of an effective anthelmintic twice a year. Give the first dose a month before the onset of the rainy months, and the second one at the peak of the rainy months. The second dose is usually optional for confined animals. Subsequent anthelmintic applications may be given when necessary. Seek the advice of a licensed veterinarian.

The benefits of strategic deworming include reduced worm burden; lower mortality by up to 70%; and preserved efficacy of anthelmintics used.

Using chemical anthelmintics

In the past, indiscriminate use of chemical dewormers has led to the development of anthelmintic resistance when the worms no longer respond to the effect of the anthelmintic. To prevent resistance, collect fecal samples and have them analyzed to identify the worm profile. The results will determine the appropriate anthelmintic to use.

Deworm using a broad-spectrum dewormer, e.g., Ivermectin. There are groups of anthelmintics available in the market, and each having a different mode of action. Consult a licensed veterinarian regarding the appropriate dewormer for your animals.

Every year, rotate the use of these anthelmintic groups to prevent anthelmintic resistance. Properly administer the drug to ensure that effective dosage is given. Underdosing may also lead to anthelmintic resistance.

Using shrubs and tree leaves

The use of herbal plants with deworming properties has gained renewed interest in the development of anthelmintic resistance and preference for organic products.

Table 1. Recommended shrubs and trees for strategic deworming (Alo 2003).

Deworm using any of the following plants (Table 1) given as fresh feed, decoction (extract from boiling), or ‘bolus’ (a pre-measured dose of medicine shaped into a large solid pill to be swallowed). Regular use of these shrubs and tree leaves improved the general condition of animals and reduces the anthelmintic treatments to once a year or none at all.

Managing the health status of animals

Observe proper hygiene to mitigate the ill effects of the La Niña phenomenon. During
transportation, pigs should be bedded with straw or other materials with high insulating properties. Water and feeds should be readily available for trips longer than 24 hours. If vaccination is scheduled, administer vitamin-mineral-electrolyte supplements two days before and after vaccination. However, it is important to avoid stress from handling and the vaccination process.

This practice is applicable in all areas in the Philippines. This farm practice can be labor-intensive, but it helps maintain and improve animal health status and improve animal productivity.

Fig. 2. Curtains to protect poultry and swine houses or pens during the wet

Requirements for adoption

– Curtains (Fig. 2)
– Disinfectants
– Rice straw or rice hulls
– Warming devices such as heaters or infrared lamps
– Vitamin-mineral-electrolyte supplements

Support system
– Good nutrition and sanitation program
– Information materials


Check roofs for any leak prior to the onset of the wet season.

Provide swine and poultry houses or pens with curtains. Provide ventilation to maintain adequate air circulation and avoid buildup of ammonia in the house or pen.

Always keep the pens clean. Manure and urine buildup can contribute to the accumulation of ammonia that affects the respiratory system of animals.

Always check improvised warming devices such as coal and gasera to prevent incidents.

This appeared in Agriculture Monthly’s August 2018 issue. 

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