Lamb Liveweight Gain Trial

In 2014, DLF established a large trial on a commercial farm in West Otago to compare the performance of lambs on five different grass cultivars.  2.47 hectares of each grass were planted (without clover), and lambs are grazed simultaneously with measurement of their growth rates, as well as meat yield and scanning percentages.  Scroll down to read the results from 2015.



On 22 January 2015, a large mob of ewe lambs were weighed and a group close to the mean were selected.  These were randomly divided into five mobs and placed in the five trial pastures. They remained there until 3 June 2015, during which time they were mated.  Extra lambs were added as required to maintain the same pasture cover in all treatments. The control pasture was a popular perennial ryegrass that is currently rated with five stars for that location in the Forage Value Index system.


There were small differences in the live weight gain (LWG) per lamb per day (Fig. 1).  There were no differences in meat yield.


Figure 1.  LWG per lamb per day (2015)


There were however larger differences in the LWG per hectare (Figure 2), a function of some grasses being able to carry more lambs per hectare.


Figure 2.  LWG per hectare (2015)


The most surprising result was the in-lamb scanning percentage of the ewe hoggets that were grazed on the five grasses before and during mating.  The higher scanning percentage in hoggets grazed on Jeta cannot be explained by differences in LWG when averaged over the 132 days of the trial, or by their final body weights.  The only likely explanation is that at a critical point in the ovulation cycle the nutritional value of Jeta was better than the other four grasses.


Figure 3.  In-lamb scanning percentage of ewe hoggets (2015)


For the 2016 results, please send an email by clicking here.