Variation in the characteristics of milkfat from pasture‐fed dairy cows during late spring and the effects of grain supplementation.

Abstract

Sources of variation in milkfat characteristics were determined after approximately 115 days-in-milk for Friesian cows that had calved in spring and grazed ryegrass-white clover pastures.

Variation in the composition of milk protein from pasture‐fed dairy cows in late lactation and the effect of grain and silage supplementation

“…Nevertheless, marked variation in the concentrations of milk components both between cow and within cow was recorded in the present study of Friesian cows in late lactation (Table 3). The variation in concentrations of fat was greater than that for concentrations of protein and lactose (Table 3), which was consistent with previous results (Johnston & Viggers 1983;Barnes et al 1989;Rook et al 1992;Mackle et al 1997). …”

“…Variation was larger between-cow than withincow for nearly all parameters measured (Tables 3-5), which is consistent with the findings of Mackle et al (1997). This implies that in a study of factors affecting milk protein composition, there is a statistical benefit in increasing cow numbers rather than increasing the frequency of sampling.…”

“…The level of variation, however, was similar to that reported in mid lactation by Mackle et al (1997), although Johnston & Viggers (1983) reported greatest variation in the concentrations of milk components during early and late lactation.…”

“…The chemical composition of pasture and maize grain, botanical composition of pasture, and N contents of pasture silage were measured as described by Mackle et al (1997). Silage DM digestibility was determined using the pepsincellulase technique described by McLeod & Minson (1978).…”

Relating texture properties and composition of bovine fat tissue

“…Including C 18:0 instead of C 14:1 and C 16 Accordingly, the control fat with an elevated proportion of oleic and linoleic acids and a low proportion of stearic acid had the lowest percentage of solid fat at 20°C. Similar findings were described for milk fat, where SFC was closely correlated with C 18:1, cis as well as C 16:0 [31,32].…”