Effects of stearic acid supplementation and starch concentration in close-up diets on performance and metabolic responses of transition dairy cows

Prepartum nutrient intake and colostrum yield and composition in ruminants

“…Research in dairy cattle demonstrates that increasing dietary energy by shifting the starch:NDF ratio does not impact colostrum yield. Daneshvar et al (2020) found that altering close-up diet starch inclusion from 20.8% to 25.8% by partially replacing wheat bran with corn and barley did not affect colostrum yield. Larger shifts in dietary starch content (magnitude of difference: approximately 12% to 15%DM) yielded similar colostrum production ( Richards et al, 2020 ; Fischer-Tlustos et al, 2021b : milked within 12 h of calving) despite crude protein ( CP ) and MP intake not always being balanced across treatments ( Richards et al, 2020 ).…”

“… Hare et al (2021) demonstrated that increasing the proportion of dietary starch fed to beef cattle affected colostrum fat concentration, decreased protein concentration, and increased colostrum lactose concentration. Yet, in dairy cattle, colostrum macronutrient composition (CP, fat, and lactose) is largely unaffected by starch inclusion ( Dunn et al, 2017 ; Daneshvar et al, 2020 ; Fischer-Tlustos et al, 2021b ). There is generally a lack of response on colostrum fat concentration and yield, although Mann et al (2016) observed that fat yield tended to increase with greater ME intake.…”

“…Late-gestation fat inclusion rate and source have not been shown to affect first-milking colostrum production in dairy cattle, either when NE concentration was maintained ( Sun et al, 2022 ) or when it was not ( Daneshvar et al, 2020 ). To the authors’ knowledge, colostrum yield in beef cattle fed differing fat inclusion rates or sources has not been reported.…”

“…Colostral macronutrient concentrations are usually unaltered by dietary fat content and source for cattle ( Jaurena and Moorby, 2017 ; Daneshvar et al, 2020 ). Notably, when the macronutrient profile was affected, colostrum fat concentration was consistently reduced by increased dietary fat provision and source ( Salehi et al, 2016 ; Daneshvar et al, 2020 ). Dietary fat intake and source also increased colostrum protein concentration ( Salehi et al, 2016 ).…”