Coccidiosis- Baycox and Vecoxan in weaned Angora kids
By Dr Mackie Hobson BSc(Agric),BVSc

1. Drugs
2. Field Studies

Baycox and Vecoxan Field Study- Angora goat kids

Coccidiosis is one of the most important diseases affecting Angora goat kids. The impact of chronic coccidiosis, which results in stunted growth, poor hair production, and lowered resistance to other diseases, is a major problem in Angora goat kids that have been weaned.

In trials on lambs treated with Toltrazuril (Baycox) and Diclazuril (Vecoxan), results showed a drastic reduction in the most pathogenic coccidial species in LAMBS. (Reference: Efficacy of Toltrazuril 5% Suspension (Baycox®, Bayer) and Diclazuril (Vecoxan®, Janssen-Cilag) in the Control of Eimeria spp. in Lambs: Manuela Diaferia1 (*), Fabrizia Veronesi1, Giulia Morganti1, Lucio Nisoli2, Daniela Piergili Fioretti1)

The results of this study on lambs are reflected in the graph below showing the efficacy of the treatments Baycox and Vecoxan :

• Group C is the control where there is zero efficacy (no reduction in the Oocyte count)
• TOLT Group are the lambs treated with toltrazuril (Baycox)
• DICL Group are the lambs treated with diclazuril (Vecoxan)

In studies in lambs, Baycox’s average efficacy remained extremely high (>90 %) for 9 weeks, while the duration of efficacy of Vecoxan reduced sharply after 2 weeks

However, reports from Mohair producers both to manufacturers and the industry vet suggested this same efficacy was NOT occurring in weaned Angora goat kids. So what is happening in ANGORA GOAT KIDS

1. Field study 2019

Firstly in a field study by Mohair SA (2019), on weaned ANGORA KIDS over a longer-term (6 -7.5 months) where treatments of Baycox/Vecoxan were given roughly every 2 months, it was found that there was no long term reduction in the cocci faecal oocyte counts or increased weight gain when compared to the control over the treatment period. (See below)

The kids were born in mid-August and were first treated with Baycox in mid-November. They were shorn on the 10^th of January, and we started the study on the 22^nd of January.

Kids were randomly divided into the study groups (35 in each group). They were tagged and weighed.

• BAYCOX Group: The Kids were treated 4 times over the 212-day study (about 7.5 months).

Treated with Baycox 5% on day 0, 40, 124, 179 (The kids were weighed and faecal samples were taken on day 0, 26, 40, 70,105,124,179,212)

• VECOXAN Group. The Kids were treated with Vecoxan three times over a period of 182 days (about 6 months). Treated on days 40, 124, and 179.

The question: Why did the kids treated with BAYCOX and VECOXAN not have lower oocyte counts than the control (untreated group) after a number of repeated treatments?

The initial thoughts were that:

• Maybe the treatments did work? or
• The duration of efficacy with Angora goat kids was not that of the studies on lambs.

2. Field study 2022

With these questions in mind, a second study was conducted in 2022

The objective of the field study was to:

• Check the efficacy of both Baycox and Vecoxan over the initial 2 week period after treatment.
• Try to find an explanation for the poor long term results of the treated groups over the 6 months in the 2019 study.

Study 2.1 (Vecoxan)

Method:

20 randomly selected kids (5 months old, 13 -22kg) were divided into groups.

1. CONTROL (No treatment) (n=10)
2. VECOXAN group -Treated 0.6ml/kg (6ml/10kg). This is higher than the manufacturer’s guidelines of 0.4ml/Kg. (n=10)

• The groups were kept on the same pasture with the rest of the flock (untreated).
• Faecal samples were taken on days 0, 4,7 and 14 after treatment and analysed by Grootfontein.

It is clear from the graph that the initial efficacy of Vecoxan was excellent, but the duration was limited, with the treatment group returning to control levels by 2 weeks after treatment.

Study 2.2 (Baycox)

Method:

30 randomly ram kids were weighed and divided into 2 treatment groups. Weight ranged 17.8-27kg (average 21.8kg)

1. Control (no treatment)
2. Baycox (dosed 6ml/10kg - 10ml each

All goats were kept under the same environmental conditions, faecal samples were taken on days 0, 7, 14, 21 and sent to Grootfontein labs

The results were very similar to the Vecoxan study, with Baycox showing excellent efficacy in the short term but levels also returning to the control level by 2 weeks after treatment. This did NOT reflect the licensed study on lambs where the efficacy lasted 9 weeks and reflects the results of the 2019 study where no reduction of oocyte counts compared to the control when sampled more than 2 weeks after treatment.

Discussion

The idea is that the short duration of treatment would allow repeated exposure and allow an acquired immunity to develop in the kids. However, over a period of 6-7 months, there was no difference in the oocyte counts and weight gains in the Mohair study in 2019 when the kids received 3 Vecoxan and 4 Baycox treatments over the study period.

A possible explanation would be that Angora goat kids have poor innate (non-specific responses without prior exposure) and poor acquired (adaptive) immunity.

SEE https://www.angoras.co.za/article/immunity-in-angora-goats

If the acquired immunity was effective, we should see:

• fewer incoming sporulated oocysts establishing themselves
• reduced numbers of the developing stages able to invade and establish themselves in the intestinal wall and
• intestinal stages being rejected by the goat.

This should result in fewer oocytes being excreted in faeces. This is, however, not what we are seeing in Angora goat kids over the extended period of 6-7month period in 2019

Acquired (adaptive) immunity is the immune response when recognising specific antigens with the development of a very specific immune response (antibody-mediated, cell-mediated, or both) and with the development of memory cells. (T and B lymphocytes).

This may result in another possible complication that may play a role in what we are seeing in Angora goat kids. That is the development of Lymphocytic-Plasmacytic-Enteritis (LPE) due to an abnormal immune response by the Angora goat kid.

SEE https://www.angoras.co.za/article/lymphocytic-plasmacytic-enteritis-lpe-in-angora-goats

This could also explain the poor growth and production post-exposure to the Coccidiosis.

• It is critical to review ALL FACTORS contributing to Coccidiosis and particularly reducing the PREDISPOSING FACTORS

SEE ARTICLE ON COCCIDIOSIS https://www.angoras.co.za/page/coccidiosis

Also, see the article on OFF-LABEL cocci treatments https://www.angoras.co.za/article/off-label-coccidiosis-treatments-angora-goat-kids

Dr Mackie Hobson (Mohair SA)