Meat-type sires leave mark on ewe colostrum
CROSSBRED ewes sired by meat-type rams produce similar amounts of immunoglobulins (IgGs) in their colostrum but lower yields of fat than milk-type ewes.
This implies that though lambs from meat-type crossbred ewes may have sufficient protection against disease, after a full feed of colostrum at birth, they may be at more risk from hypothermia than lambs suckling milk-type crossbred dams.
Sheep on trial at Harper Adams included 30 crossbred ewes aged two to four years and scanned as carrying triplets. They included eight Charollais x Cambrdge and eight Charollais x Lleyn, classed as meat-type ewes, together with 14 Friesland x Lleyn, classed as milk-type.
Ewes were housed three weeks before lambing, fed an 18% crude protein roll rising to 1.5kg a head a day before lambing and offered hay ad lib.
Colostrum yield and composition were measured at one hour and 12-16 hours after lambing with samples taken at each milking and analysed for total solids, ash, fat, protein and IgG. An hourly secretion rate between 12-16 hours was calculated which allowed colostrum yield and constituents to be estimated over the first 24 hours.
There was no effect of ewe type on total solids, ash, fat or protein content at one hour or at the 12-16 hour stage after lambing. But meat-type ewes produced colostrum containing more IgG one hour after lambing than milk-type ewes and with a similar result at the 12-16 hour stage.
Milk-type ewes produced a greater yield of fat at one hour and 12-16 hours and over 24 hours. These ewes also produced greater yields of total solids, ash and protein than meat-type ewes at 12-16 hours and over 24 hours.
Lambs from meat-type crossbred ewes may have sufficient protection against disease after a feed of colostrum, but may be more at risk of hypothermia compared with lambs from milk-type crossbred dams.
• Spring grazing benefits.
• Ewe colostrum differences.
• Wilting can lift silage intakes.