I attended the annual New Zealand Society of Animal Production conference (2nd-4th July) held at Massey University. I have summarised a few of the sheep papers that I found most interesting. All of the papers from the conference can be found here.
Does age and sex affect meat quality in older lambs?
Speaker: Beverley Thomson
In the Hawkes Bay, many lambs are trading lambs that are brought and sold depending on pasture supply on farm. These trading lambs are sold for processing between 12-15 months of age. This study compared old season (14 months old) and the traditional new season lambs (3.5 months old) to determine if there was a difference in meat quality. Three different sex classes; ewe, cryptorchid and ram lamb were also compared to determine if there were a difference in meat quality among sex classes.
The meat was aged for 8 days and then frozen. There were 150 consumers in the taste panel residing in New Zealand.
The short loins from 10 new season ram lambs (3.5 months of age) and 10 old-season ram lambs (14 months of age) of similar weights and grades were compared. The samples from the new-season lambs scored slightly better for taste, tenderness and juiciness, but there was no difference in odour.
The short loins from 10 ewe, 9 cryptorchid and 9 ram lambs with similar carcass weights were compared. The researchers found no difference in eating quality among the three different classes of stock.
There was no significant difference in the taste characteristics from a NZ taste panel between sex. There was a very slight improvement in meat quality for younger lambs.
Key Points:
No difference in taste between the sexes
Slight improvements in meat quality for younger lambs
Does stocking rate of singleton ewes during lambing and lactation affect performance?
Speaker: Paul Kenyon
Multiple bearing ewes have a greater nutritional demand than single bearing ewes. Sheep and beef farms don't use much supplementary feed, therefore, the majority of feed intake comes from grazing pasture. Ewes are set stocked prior to lambing, this means that the growth rate of the pasture is similar to the demand of the ewes. Decreasing the stocking rate will provide more feed for the ewes, however, increasing the stocking rate will restrict the feed to the ewes. This study looked at different stocking rates of singleton-ewes, either 11, 13 or 15 ewes per ha, during lactation on ewe and lamb performance to weaning.
The results of the study suggested that when pasture covers are high, a stocking rate of up to 15 can be used with no negative impact on the ewe or lamb. A stocking rate of 11 or 13 when pasture covers are low resulted in slightly lighter ewes at weaning, but there were no differences in lamb weaning weights.
Key Points:
Stocking rate had no impact on lamb weaning weight
Single bearing ewes have a buffering ability so can withstand periods of feed restriction
Effect of a fodder beet or lucerne-chaff-based diet on triplet-bearing ewe live weight, body condition score and lamb birth weight
Speaker: Sue McCoard
The feed requirements of triplet-bearing ewes are greater than twin or single bearing ewes. The triplet-bearing ewes are limited by their stomach capacity, making it difficult to consume enough pasture to meet energy demands. This study examined the difference in ewe weight, ewe body condition score and lamb birth weight between a fodder beet (FB) or lucerne based diet. The diets were balanced for crude protein, vitamins and minerals.
Triplet-bearing ewes during mid-pregnancy were randomly allocated to a lucerne-based (65% of dry matter [DM] n=12) or FB based (56% FB bulb; n=16) diet. The lambs were weighed two hours after birth. The ewe weight and body condition score were no different between the diets.
The FB-fed ewes consumed less than the lucerne diet ewes as gestation advanced closer to lambing.
There was an effect of diet on the birth weight of female lambs but not male lambs, where FB-fed ewes had heavier female lambs. This has been reported in previous studies due to the increased supplementation of the amino acid arginine.
These results indicate that supplementing a FB-based diet with additional protein, fibre and minerals can maintain triplet-bearing ewe body condition score and weight and can improve female lamb birth weight compared to those born to lucerne fed ewe.
Key Points:
A fodder beet diet resulted in heavier female lambs at birth. There was no change to the male lamb weights between diets.
The was no difference in the pregnant ewes weight or body condition score between the fodder beet or lucerne diet
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