Effect of feeding sorghum ergot (Claviceps africana) to sows during mid‐lactation on plasma prolactin and litter performance

Abstract

Diets containing 3% sorghum ergot (16 mg alkaloids/kg, including 14 mg dihydroergosine/kg) were fed to 12 sows from 14 days post-farrowing until weaning 14 days later, and their performance was compared with that of 10 control sows. Ergot-fed sows displayed a smaller weight loss during lactation of 24 kg/head vs. 29 kg/head in control sows (p > 0.05) despite feed consumption being less (61 kg/head total feed intake vs. 73 kg/head by control sows; p < 0.05). Ergot-fed sows had poorer weight gain of litters over the 14-day period (16.6 kg/litter vs. 28.3 kg/litter for controls; p < 0.05) despite an increase in consumption of creep feed by the piglets from the ergot-fed sows (1.9 kg/litter compared with 1.1 kg/litter by the control; p > 0.05). Sow plasma prolactin was reduced with ergot feeding after 7 days to 4.8 microg/l compared with 15.1 microg/l in the control sows (p < 0.01) and then at weaning was 4.9 microg/l compared with 8.0 microg/l (p < 0.01) in the control sows. Two sows fed ergot ceased lactation early, and the above sow feed intakes, body weight losses with litter weight gains and creep consumption indirectly indicate an ergot effect on milk production.

A review of potential contaminants in Australian livestock feeds and proposed guidance levels for feed

“…In one Canadian study (Dignean et al 1986) milk production was not affected when sows were fed 0.2% rye ergot (4.5 mg alkaloids/kg of diet) from breeding until weaning, but the authors noted that their results were apparently at variance with other studies showing agalactia produced by lower ergot concentrations. Studies with sorghum ergot fed to sows before farrowing, found adverse effects on milk production at alkaloid concentrations of 1.4-7 mg/kg (Kopinski et al 2007), but higher concentrations were tolerated after lactation had commenced (Kopinski et al 2008c). Nevertheless a concentration of 0.02% rye ergot (0.4 mg alkaloids/kg) should provide an adequate safety margin for weaner and breeder pigs.…”

“…The tolerance of nonlactating pigs is also not clear but a Canadian study (Oresanya et al 2003) suggested maximum tolerances of 0.1% ergot (2 mg alkaloid/kg) and 0.05% based on growth rates and feed intakes respectively for weaner pigs (7-20 kg liveweight). Other studies have shown that grower and finisher pigs are more resistant and 10-15 mg/kg can be tolerated with only minor effects on feed intakes that can be masked with palatable ingredients (Whittemore et al 1977;Mainka et al 2005;Kopinski et al 2008aKopinski et al , 2008bKopinski et al , 2008c. One Australian study (Bakau et al 1988) found reductions in growth rate and feed intake of pigs fed 0.75% ergot (alkaloid content not reported), which were exacerbated by higher temperatures (35 C).…”

“…Sorghum ergot alkaloids have similar effects as rye ergot alkaloids in reducing circulating prolactin concentrations, with severe impact on milk production of sows (Kopinski et al 2007(Kopinski et al , 2008c and cows (Moss et al 1999;Blaney et al 2000c). They also have vasopressor effects, reducing peripheral blood circulation and interfering with heat regulation in cattle .…”

“…It is proposed that sorghum ergot alkaloids in the total diet of non-lactating ruminants should be restricted to 0.3 mg alkaloids/kg. This will most commonly be equivalent to 0.1% ergot, but could rarely but conceivably be present in a sample containing 0.02% of mature sclerotia (Kopinski et al 2008c). Consequently, the proposed guidance limit for ergot should be supported by physical observation of the presence or absence of mature sclerotia, and by alkaloid assay when risks are higher.…”

The role of mycotoxins in pig reproduction: a review

“…The effect on milk production is caused by prolactin inhibition (Whitacre and Threlfall, 1981;Kopinski et al, 2007). A concentration of 0.3% sclerotia in the lactation feed is sufficient to cause agalactia in 50% of sows.…”