Reseach from British Society of Animal Science Conference

Reducing number of milkings a week and effects of calving assistance on saleable milk were just two of the topics up for discussion at this year’s British Society of Animal Science Conference, Belfast. Sarah Trickett reports

Dairy farmers can reduce labour costs and improve lifestyle in family operated farms by skipping one milking weekly, said Teagascs’ Bernadette O’Brien at the British Society of Animal Science Conference, Belfast.

“Milking cows twice a day is a time constraining task for dairy farmers and omitting one milking weekly, particularly a weekend afternoon milking may offer an opportunity to reduce labour costs if the farm employs hired labour or alternatively improve lifestyle in a family operated farm situation,” she said.

The study focused on the effects of 13 times a week milking at different stages of lactation compared to twice a day in terms of milk yield, composition and quality. Cows were either milked 13 times a week starting at 50 days in milk or 180 days in milk or where milked normally twice a day for the whole week.

“Milk yields, milk solids, fat, protein and lactose concentrations did not differ for all treatments as did average liveweight and body condition score. These data suggests that omitting milking one consistent occasion a week does not adversely affect overall milk yield, composition or quality,” she said.

Calving difficulties

Calving assistance triggers long term saleable milk production losses for dairy producers, according to SACs’ Alice Barrier.

Speaking at the conference, Miss Barrier explained how calving difficulty not only resulted in assistance being provided at delivery, it was also associated with still births and could lead to impaired fertility, reduced milk production and increased risk for peripartum diseases and culling. “Calving difficulty also raises animal welfare as well as economic issues,” she said.

Miss Barrier looked at how varying degrees of calving difficulty would alter production of saleable milk in UK dairy cattle over different stages of lactation. Calving difficulty scores included no assistance, farm assistance with or without malpresentation, vet assistance with or without malpresentation and caesarean section.

“We found cows needing farm staff or vet assistance but only when the cow was not malpresented resulted in a decrease in saleable milk. Not only did these losses occur in early stages of lactation they persisted over time and appeared to be higher by the end of lactation. These results support the idea calving assistance triggers long-term saleable milk production losses,” she said.

The lower saleable milk production may be the result of decreased milk yields by the cow as well as higher milk wastage due to subsequent poor health.

However, there was little effect on saleable milk when cows were offered assistance when there was malpresentation. “This might be because farmers assisted more quickly when malpresentation was obvious.”

Straw and TMR may not mix

Feeding straw in a TMR mix to lactating dairy cows could reduce feed intake and milk yield, Reading University’s Chris Reynolds told delegates.

“While the concept of including limited amounts of straw in milking rations is accepted as being nutritionally sound, there is little scientific evidence available. So for this reason we decided to look at whether straw and it’s method of inclusion affected production and eating behaviour in lactating cows.”

Cows were fed either a control TMR (37% maize silage, 18% grass silage and 45% concentrates), or one of two diets containing four percent straw mixed with a horizontal mixer or the same diet mixed with a vertical mixer which gave a longer chop length.

“We found cows fed straw spent more time eating and as a consequence had a lower eating rate compared to the control diet and these effects were greater for straw diets with longer chop length. Milk yield was also lower where straw was fed.”

And although this confuses what farmers may have been previously told, Dr Reynolds advised farmers to look at fibre levels in the base diet before deciding whether to include straw. “Fibre is vital in a diet and you can get effective fibre from straw. This study may not have seen benefits from straw because NDF in the control was sufficient.”

Selecting genotypes

Specific genotypes could be better suited to forage based grazing systems, according to research from the Agri-Food and Bioscience Institute, Hillsborough.

Holstein Friesians are the dominant cows on Northern Ireland dairy farms, a reflection of the high efficiency of the breed for milk production. However, achieving high levels of food intakes within grassland based milk production systems can be challenging, especially when compared with concentrate based production systems, said AFBI’s Elaine Vance.

“While increased food intakes can be achieved through management strategies, there is anecdotal evidence suggesting some cow genotypes are more suited to forage based systems than others. And for this reason we compared feed intake, feeding behaviour and grazing behaviour of Holstein Friesians and Jersey cross Holstein Friesians,” she explained.

Cows were offered conserved forage based diets and then grazing. “We found genotype had no effect on milk fat or protein yield and this is despite the fact Jersey x Holstein Friesians were lighter. Holstein Friesians did have higher intakes when indoors, however, when grazing, the Jersey x Holstein Friesian (when expressed on a metabolic liveweight basis) had greater intake potential and also spent longer grazing with fewer grazing bouts.” This could indicate genotypes incorporating some Jersey genetics could be better suited to grass based grazing systems.”

Is enough money being put into agricultural research and if not what are the consequences? Hear some of the thoughts from delegates at this year’s British Society of Animal Science Conference online at www.fwi.co.uk/bsasvideo