Three commercial sheep farms in a hot, tropical climate ( Yucatán peninsula, Mexico) were used to compare body condition score (BCS) ≤ 2 and FAMACHA© score ≥4 or ≥ 3 as criteria to identify ewes with FEC ≥750 epg and to confirm whether that FEC threshold allowed maintaining a large proportion of animals with no anthelmintic treatment.
BCS and FAMACHA© scores were determined monthly. Fecal samples were collected from ewes (hair sheep) showing FAMACHA© scores ≥4, BCS ≤2, or both. All sampled ewes with FEC were treated with an anthelmintic. Choice of drug was dependent upon prior efficacy.
BCS ≤ 2 was determined to be the best criteria for finding ewes with FEC ≥ 750 epg, with only 1.1% false negatives. Meanwhile FAMACHA© ≥4 or ≥3 failed to identify half the ewes with FEC ≥750 epg, resulting in 50 to 55% false negatives. Using a threshold of ≥750 epg resulted in 63.5% of ewes being maintained with no anthelmintic treatment.
The researchers concluded that a targeted selective treatment (TST) scheme should focus on ewes with BCS ≤2 and that FEC can be used to avoid unnecessary anthelmintic treatments. The FEC threshold could be increased to reduce the number of animals requiring treatment. FAMACHA© scores could be used to identify animals with anemia.
Source: Small Ruminant Research, October 2018. Read abstract.