Lamb finishing, monitoring worm burdens and preparing for breeding

Michael Gottstein, Head of Sheep Knowledge Transfer at Teagasc, tells us about Amy and Ross Jackson’s mixed sheep and tillage organic farm in Co. Tipperary, highlighting lamb performance and drafting, the use of faecal egg counts to monitor worm burdens and preparations for breeding.

Amy and Ross Jackson farm just under 51ha in Lacka, Carrig, Birr, Co. Tipperary. The farm is run as a mixed sheep and tillage farm on exceptionally dry, free-draining land on a part-time basis as both Amy and Ross work off farm.

The farm has been operating as an organic farm for the past 10 years. Farm enterprises consist of a mid-season lambing ewe flock of approximately 120 ewes (including ewe lambs), a few horses and approximately 16ha of spring barley (distilling) and 12ha of spring oats (porridge oats).

As the farm is not allowed to apply chemical nitrogen, a number of companion forages have been sown to aid forage production. These consist of 4ha of red clover, primarily for silage production, 10.5ha of multispecies swards and a further 8.5ha of grass-clover swards.

Table 1: The crops grown on the Jackson farm

This year has been a challenging year for sheep farms. A difficult spring followed by poor weather and poor grass growth has resulted in poorer lamb performance and higher lamb mortality on most farms. The Jackson farm is very well set up from an infrastructure (fencing, housing and animal handling facilities) point of view. The good infrastructure helped enormously this spring in reducing lamb mortality, as lambs were able to be held in for longer during periods of adverse weather. That said the inability to apply chemical nitrogen which is a tool being used by conventional sheep farmers has been challenging and grass has been tight for most of the grazing season.

Finishing lambs

Lambs were weaned at the end of June. At weaning time, eight lambs (4.8%) out of 166 lambs were drafted for slaughter. Table 2 below outlines the percentage of lambs in the different weight categories at weaning time.

Table 2. Percentage of lambs in different weight categories at weaning

Since weaning, lambs have been grazed on the best quality grass available on the farm. One hectare of a forage / grass / clover crop was sown in May and a finishing group of 37 of the heaviest lambs on the farm (35kg +) have been grazing this in addition to being supplemented with a small amount of oats.

34 of these lambs were identified for drafting at the time of writing, with 25 destined for ICM and the remaining nine of the heaviest lambs sent to a local butcher to be sold as box lamb under the Lacka Organic lamb label. As lambs in the grass only group grow into weights above 35kg, they will be moved into the finishing group.

Monitoring worm burdens

Faecal egg counts are carried out to establish when treatment for stomach worms is needed. A faecal egg count carried out at weaning indicated the need for treatment. The product used to treat the lambs with was an Ivermectin based wormer. A second faecal egg count taken from the same lambs 14 days later showed a reduction in egg count of only 82%, indicating that the product was not effectively reducing the egg count below 95%. Therefore resistance to Ivermectin is now suspected. Post treatment, the egg count in the lambs rose rapidly and a second treatment was warranted. A levamisole based wormer was used for the second treatment. The big challenge with using levamisole based product is the significantly longer withdrawal period. Organic farmers selling lambs for slaughter have to double and in some cases triple the withdrawal period.

Ewe management

At the time of writing, all ewes are being weighed and body condition scored. Any culls identified will be drafted and the remaining ewes will be separated into two groups. The first group will be ewes that need to gain significant weight prior to mating and these will be give priority access to forage. The second group will be those ewes that are in good body condition and these ewes will be used to clean up after the first group.

Tillage

Tillage crops are currently being harvested. The barley is averaging approx. 4.25 t/ha whereas the oats are coming in a bit better at 5t/ha. This is the first year that all of the straw will be baled with about 50 bales being retained for home use and the remainder being sold. Normally the straw is chopped. Over two-thirds of the crops were harvested on 15-18 August, allowing a forage crop of between 4ha-7ha of a Gorilla / Redstart mix to be sown post-harvest to make extra fodder available for the sheep while at the same time holding soil nutrients. 

This article first appeared in the Farming Independent

Also read: Ewe BCS: Start now to ensure ewes are fit for the year ahead