Cow/calf treatment with IVOMEC 1% Injection provided significant productivity benefits under a variety of grazing conditions.

Utah: A total of 137 cow/calf pairs in 2 herds were used to evaluate the productivity benefits of treatments in 2 trials with IVOMEC undertaken under vastly different conditions. Trial 1 was on irrigated pasture and Trial 2 on native and reseeded pastures, desert range, and mountain range.
In Trial 1, spring-born calves were matched by weight and divided alternately with their dams between two groups:

• Group 1 was left untreated as the Control group
• Group 2 was treated with IVOMEC in May and June

The two groups grazed adjacent pastures. In the 2 years before the trial, an exclosure clipping method used to assess biomass productivity had shown the two pastures to be equivalent. In Trial 2, the allocation procedure was similar.
Cows and calves were treated with IVOMEC in April and calves were retreated with IVOMEC in June. In this trial, the two treatment groups were mixed together at pasture. In Trial 1, adjusted 205-day weaning weights were significantly greater for calves in the group that received IVOMEC. At trial’s end, Control calves weighed 191 kg whereas the calves treated with IVOMEC weighed 204.0 kg (P<0.05). In Trial 2, treatment of calves only, or of cows and calves, resulted in significant increases in weaning weight (P<0.05).

Overall, the results demonstrate the value of effective parasite control in suckler herds. Treatment with IVOMEC produced significantly greater weaning weights under conditions of irrigated grazing and of extensive range grazing.

Bagley et al, 1992, Agri-Pract. ,13:24-28

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Cow/calf pairs treated with IVOMEC 1% Injection showed improved productivity gains.

Georgia: Two herds were used in the first study, involving 469 Hereford cows and their calves. In one herd, three pasture groups were randomly assigned between two groups:

• Group 1 was left untreated as the Control group
• Group 2 cows were treated with IVOMEC in late spring and calves born between January and April were treated with IVOMEC in late spring and midsummer

The trial started in late May and finished in September when the calves were weaned. During the trial, calves that were treated with IVOMEC gained significantly more weight, 15.9 kg, than untreated calves (P<0.05). The productivity results are summarized in the chart.

The results of this study were confirmed by a later trial, using a similar protocol, in which 466 calves treated with IVOMEC gained significantly more weight, 12.5 kg, than Control calves in the period prior to weaning (P<0.05).

Ciordia et al, 1984, AJVR, 45:2455-2457

Ciordia et al, 1987, Vet. Parasitol., 23:265-271

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In the following two North Dakota studies, herds treated with IVOMEC 1% Injection showed significantly improved productivity.

North Dakota (1): A 2-year field study in North Dakota involved four suckler herds, with 548 cows in the first year and 522 in the second. In each year and in each herd, cows were randomly allocated among four groups:

• Group 1 was treated with IVOMEC in the spring and autumn
• Group 2 was treated with IVOMEC in autumn
• Group 3 was treated with IVOMEC in the spring
• Group 4 was left untreated as the Control group

Over the 2-year period, 1,046 calves were weaned. Their weights were adjusted to 205 days and comparisons made between groups across all herds. Over the 2-years of the study, a higher proportion of cows treated with IVOMEC became pregnant, but the difference from Controls was not significant. There was a significant advantage (P=0.02) of 7 kg, compared to calves from untreated cows, in the weaning weights of calves from cows treated with IVOMEC.

Wohlgemuth and Melancon, 1988, Agri-Pract, 9:23-26

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North Dakota (2): Three herds including pure-bred Simmentals, Charolais, and Hereford cross-breds were used in a two - year study in which 953 calves were weaned. Each herd was randomly allocated among four groups:

• Group 1 cows and calves we re treated with IVOMEC in autumn and late June
• Group 2 cows were treated with IVOMEC in autumn
• Group 3 calves were treated with IVOMEC in late June
• Group 4 was left untreated as the Control group

Calves in Groups 1 and 2 showed a significant increase in body weight gain of <9 kg compared to the Control group (P<0.05). These studies provide further confirmation of the benefits of using IVOMEC for parasite control in cow/calf herds.

Wohlgemuth et al, 1989, Bov. Pract. , 24:61-66

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