Organic minerals may cut cell counts in half

22 February 2002




Organic minerals may cut cell counts in half

By Richard Allison

FEEDING organic forms of minerals can halve milk somatic cell counts, while long-term use will improve herd fertility, according to Irish research.

At the recent Alltech conference held in Birmingham, University College Dublin researcher Maurice Boland said better mineral nutrition can help tackle poor dairy cow fertility. "Gestation is the period of greatest mineral drain for cows. This is reflected by the higher incidence of diseases around calving when mineral reserves are low."

Minerals important for maintaining fertility include copper, zinc, molybdenum, selenium and chromium. Prof Boland believes correcting the supply of these minerals improves ovarian activity after calving, cuts embryo mortality and increases the intensity of oestrus behaviour.

"Compared with standard minerals, organic minerals are more available to the animal, resulting in a better supply to the target tissues. They are also less prone to interactions with other minerals."

Trials at the university found that feeding organic copper, zinc and selenium to dairy cows increased conception rates to first service from 58% to 65%. Cows also reached first ovulation five days earlier compared with those fed standard minerals.

"Somatic cell counts were also reduced by 40%. But blood analyses found that cows fed standard minerals had a normal mineral status. This indicates that producers will see benefits in cows with a normal mineral status."

But improvements in fertility will be subtle on most units and will take some time to appear, warned Prof Boland.

In a separate study feeding organic minerals, milk yield was increased by 285kg during the first 84 days of lactation. This is not surprising because yields tend to be depressed with higher cell counts, said Prof Boland.

But ADAS researcher Bruce Cottrill highlighted that reductions in milk somatic cell counts when feeding organic selenium are not always apparent. "This may reflect differences in forage selenium content."

ADAS lab data shows grass silage is very different in selenium. Maize silage contains less selenium than grass silage which has implications for herds fed high maize rations, he added. &#42


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