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Why do we focus on lifting low body condition ewes?

Ewes better than condition score 2 produced 10kg more lamb than ewes at condition score 2 or less!

Some say StockCARE® is all about having fat ewes! However, our approach has recently been confirmed by a study done by Ginny Dodunski, Totally Vets, Feilding.

On 5 Manawatu hill country farms, before start of mating, she identified about 60 ewes at score 2 or less (Thin), 30 condition score 2.5 (Medium) and 30 at condition score 3 or better (Fat). The ewes were all run together with the other ewes in the flocks. The study ended at weaning.

For this article we have combined the Medium and Heavy ewes to compare ewes at condition 2 or less (LBCS) with ewes better than condition score 2 (HBCS).

Summary of results

Liveweight

Table 1. Average ewe liveweight (kg)

	HBCS ewes	LBCS ewes
Ram in	62.5	55.5
Ram out	63.5	57
Scanning	59	54
Pre-lamb	62	57
Docking	58	55
Weaning	60	57

On average ewes with higher BCS were heavier but there was a wide variation in liveweight at each BCS:

1. 39kg to 66kg

2. 40kg to 73kg

3. 46kg to 86kg

4. 58kg to 78kg

This reinforces our approach to identifying ewes that need a hand – do it by condition scoring not weighing.

Dags

Average dag score for HBCS ewes was 1.3 compared to 1.6 for LBCS ewes.

Faecal egg counts

FEC results for HBCS and LBCS ewes are shown in Figure 1. These ewes were not drenched during the study. Egg counts aren’t that high but LBCS ewes had higher egg counts all year.

At Ram out half the LBCS ewes were drenched with a triple combination. There was a 1.9kg advantage for the drenched ewes by scanning.

Figure 1. Average FEC for HBCS and LBCS ewes

Lamb Production

HBCS lambs were 1kg heavier at weaning. The actual weaning weights are not presented, but assuming LBCS lambs were 27kg the HBCS ewes weaned an extra 9.9kg lamb. A breakdown of the performance is in Table 2.

Table 2. Production parameters for HBCS and LBCS ewes

	HBCS ewes	LBCS ewes
Scanning %	176.5%	158%
Lamb wastage ¹	11%	21%
Ewe death rate	9.9%	17%
Ewe wastage²	21%	28%

1. Results for ewes of different condition score at scanning

2. Includes deaths, missing, dry-dry & wet-dry ewes between mating and weaning

Summary & Discussion

The study confirms the importance of ewe body condition throughout the annual production cycle.

The study could not explain why ewes were in low body condition. LBCS ewes had a higher incidence of teeth defects but 30% of the HBCS ewes had defects suggesting that teeth are unlikely to be a dominant cause.

It is easy to say that higher worm burdens cause loss of body condition but we would suggest the worm burdens are more a reflection of low body condition. In this study FEC for both groups of ewes peaked at scanning (Fig. 1) which coincides with a significant weight loss since ram out. This confirms that generally worm burdens in adult ewes are a reflection of how they are fed.