16 April 2011

3 minute read

Out-wintering yearling dairy heifers on a woodchip pad saw improvements to animal health and behaviour, largely owing to higher space allowances and better underfoot conditions than the outdoor environment.

“And the system did not seriously compromise animal performance because out-wintered animals used their feed efficiently,” said Teagasc’s Laura Boyle, who led a trial to find out how heifers would perform in an outdoor environment, compared to their housed counterparts.

“Under appropriate climatic and management conditions, out-wintering yearling dairy heifers on a woodchip pad is a good alternative to wintering indoors in cubicles,” she added.

Woodchip pads represent a low-cost alternative to housing for cattle during the winter and considering the negative welfare implications associated with housing indoors on concrete, they may also offer welfare benefits to replacement dairy heifers.

However, these animals may not be able to withstand winter weather conditions on a grass silage diet. “So we set out to evaluate behaviour, limb injuries, dirtiness scores, performance and climatic energy demand (CED) of yearling dairy heifers on two levels of nutrition kept outdoors on a woodchip pad or indoors in cubicles during the winter.”

A total of 96 10-month-old heifers were blocked and assigned in groups of eight, to one of the following four treatments in a 2×2 factorial design: indoors, silage only; indoors, silage plus concentrate; outdoors, silage only; and outdoors, silage plus concentrate.

There were three replicate groups per treatment and all animals were inspected for skin lesions and were weighed and body condition scored (BCS) at the beginning and end of the trial.

Instantaneous scan sampling and continuous all-occurrence behaviour sampling were used to collect behaviour data during two 24-hour periods. Animals were also dirtiness scored and group feed intakes were recorded during the trial.

“Significantly more comfort, social and play behaviours were recorded outdoors while trips, slips and falls were only recorded indoors,” said Dr Boyle. “Groups outdoors had significantly lower limb lesion scores at the end of the experiment and fewer groups outdoors were affected by all categories of limb lesions. That said, they were consistently dirtier than animals kept indoors.”

Low-nutrition animals had lower feed intakes, smaller BCS changes and lower average daily weight gains than high-nutrition animals. Heifers outdoors had significantly lower average daily weight gains and BCS changes, explained by lower feed intakes.

“But outdoor heifers on both the high- and low-nutrition diets and indoor animals on the low-nutrition diet had lower UFL (feed unit for maintenance and lactation) than that required to meet the daily live-weight gains they achieved.

“Heifers indoors on the high-nutrition diet gained 0.98 kg per day, but consumed 0.17 UFL more than what would be recommended to achieve a daily weight gain of 1.0 kg,” added Dr Boyle.