Effects of hogget oestrus and the lambing and milking of hoggets on the subsequent milk composition and yields of 2‐year‐old Dorset ewes

Abstract

Effects of hogget oestrus and the lambing and milking of hoggets on the subsequent milk composition and yields of 2-year-old Dorset ewes, Abstract One-hundred-and-ninety Poll Dorset hoggets were used in an experiment to determine the effects of hogget oestrus, and the lambing and milking of hoggets on subsequent milk composition and yields of the ewes as 2-year-olds. Seventy hoggets were mated to vasectomised rams and the rest to entire Dorset rams. Twenty-eight of the 83 hoggets which lambed reared their lambs, while 55 hoggets were milked twice a day. At lambing as 2-year-olds there were four groups: ewes that had reared lambs as hoggets (14); ewes that had been milked as hoggets (43); ewes that had exhibited hogget oestrus to vasectomised rams (34); and ewes that had not exhibited hogget oestrus (25). The 2-year-old ewes had a mean lambing date of 4 August and were milked twice a day until 17 November. Daily milk yields were measured every 7-14 days and the concentrations of fat, protein, lactose, and solids in the milk were measured every 7-28 days. Lambing or milking as a hogget had no effects on subsequent milk yields or milk composition as 2-year-olds. Two-year-old ewes which exhibited hogget oestrus, had lower (P < 0.001) concentrations of protein in their milk, and higher (P < 0.05) liveweights, total and mean daily milk yields, and yields of fat and lactose than 2-year-old ewes which had not exhibited hogget oestrus. Including the liveweight as 2-year-olds as A94075 a covariate in the analyses removed the effect of hogget oestrus on yields of milk, fat, and lactose but not protein concentration. Milk composition and yields of 2-year-olds were positively correlated with the milk composition and yields as hoggets. There were no beneficial effects of the lambing or milking of hoggets on subsequent milk yields as 2-year-olds but there were direct benefits of milking hoggets through the volume of milk produced and the ability to cull low-producing ewes early in their life.

Correlations of Dietary Crude Protein and Gross Energy on Blood Glucose and Urea, Milk Urea and Lactose Concentrations in Lactating Ewes

“…Furthermore, the values for SG and serum urea (SU), milk urea (MU) and milk lactose (ML) are1.9-3.1 mmol/l (Radostits et al 2000), 3.15-10.4 mmol/l (Ramos et al 1994), 2.5-6.7 mmol/l and 4.8 milk dry matter % (Gfrorer and Koch 1985), respectively. Factors affecting these indicators include the type of diet (Roseler et al 1993;Cannas et al 1998), protein and the ratio of energy to dietary protein (Bed et al 1997), housing systems (Casamassima et al 2001), estrus cycle (Knight et al 1999), stage of lactation (Flock et al 2001), pregnancy and parturition (Pulina et al 1996).…”