Working bulls are elite athletes and deserve special treatment now, either in readiness for the mating period for next year’s autumn calvings, or as they rest following the breeding season for spring 2014 births. That’s according to Liverpool University Vet School senior lecturer Karin Mueller, addressing a meeting of suckler beef producers in Welshpool.
“If a bull is below par for any reason, whether nutritional or health, his fertility can be affected,” she said. “Bear in mind that sperm production takes 10 weeks, so this time needs to be added to any recovery period from ill-health or weight-loss.”
In addition to clinical disease or under-feeding, Mrs Mueller suggested problems could also arise through two all too common oversights in bull care at this time of year: Worming and vaccinations. “If cows and youngstock justify treatment or protection, then so does the bull,” she said.
With suckler herds and worm control in mind, Mrs Mueller added that egg excretion from cows played a larger role in cow-calf transmission than previously thought. [Ref 1] She also drew parallels with dairy cows, suggesting that parasite control programmes could have direct benefit to suckler cows themselves, in addition to positive effects on calves through better nutrition and reduced pasture larval populations. [Ref 2]
In dairy cows, vet Dave Armstrong for meeting sponsor CYDECTIN® said a number of studies identified performance benefits following anthelmintic treatment. “Worms are known to reduce appetite and cows’ ability to digest forage,” he explained. [Ref 3&4] “Recent studies in grazing dairy herds have identified a daily milk yield response of around 1kg per cow.” [Ref 5]
Mrs Mueller reckoned these factors could apply equally in suckler cows. To ensure justified and responsible wormer use, Mr Armstrong advised that faecal egg counts should be done before treatment, as opposed to adopting any particular calendar option.
Both speakers also stressed the importance of COWS and SCOPS guidelines when using wormers, in particular dosing to the correct weight and leaving a proportion of the group untreated. At various times of year, Mr Armstrong said worm burdens could be present without external signs. In addition to affecting appetite and rumination, he added that a cow’s immune response to worms could consume energy that would otherwise be available for milk production, weight gain or maintenance.
For advice about faecal egg counting and wormer use in suckler cows and breeding bulls, farmers should consult their animal medicines supplier or veterinary surgeon.
C.O.W.S. = Control of Worms Sustainably (in cattle).
S.C.O.P.S. = Sustainable Control of Parasites in Sheep.
1. J Höglund et al, 2013. Veterinary Record 172: 472.
2. AB Forbes & KA Ellis 2013. Veterinary Record 172: 470-471.
3. AB Forbes et al, 2004. Veterinary Parasitology, 125, p353-364.
4. MJ Gibb et al, 2005. Veterinary Parasitology, 133, p75-90.
5. J Charlier et al 2009. Veterinary Parasitology, 164, p70-79.