Effect of dry period length and dietary energy source on energy balance, milk yield, and milk composition of dairy cows

Abstract

The objective of this study was to evaluate the effects of dry period length and dietary energy source in early lactation on milk production, feed intake, and energy balance (EB) of dairy cows. Holstein-Friesian dairy cows (60 primiparous and 108 multiparous) were randomly assigned to dry period lengths (0, 30, or 60 d) and early lactation ration (glucogenic or lipogenic), resulting in a 3 × 2 factorial design. Rations were isocaloric and equal in intestinal digestible protein. The experimental period lasted from 8 wk prepartum to 14 wk postpartum and cows were monitored for milk yield, milk composition, dry matter intake (DMI), energy balance, and milk fat composition. Prepartum average milk yield for 60 d precalving was 13.8 and 7.7 ± 0.5 kg/d for cows with a 0- and 30-d dry period, respectively. Prepartum DMI and energy intake were greater for cows without a dry period and 30-d dry period, compared with cows with a 60-d dry period. Prepartum EB was greater for cows with a 60-d dry period. Postpartum average milk yield until wk 14 was lower for cows without a dry period and a 30-d dry period, compared with cows with a 60-d dry period (32.7, 38.7, and 43.3 ± 0.7 kg/d for 0-, 30-, and 60-d dry period, respectively). Postpartum DMI did not differ among treatments. Postpartum EB was greater for cows without a dry period and a 30-d dry period, compared with cows with a 60-d dry period. Young cows (parity 2) showed a stronger effect of omission of the dry period, compared with a 60-d dry period, on additional milk precalving (young cows: 15.1 kg/d; older cows: 12.0 kg/d), reduction in milk yield postcalving (young cows: 28.6 vs. 34.8 kg/d; older cows: 41.8 vs. 44.1 kg/d), and improvement of the EB postcalving (young cows: 120 vs. -93 kJ/kg(0.75)·d; older cows: -2 vs. -150 kJ/kg(0.75)·d. Ration did not affect milk yield and DMI, but a glucogenic ration tended to reduce milk fat content and increased EB, compared with a more lipogenic ration. Reduced dry period length (0 and 30 d) increased the proportion of short- and medium-chain fatty acids in milk fat and omitting the dry period decreased the proportion of long-chain fatty acids in milk fat. In conclusion, shortening and omitting the dry period shifts milk yield from the postpartum to the prepartum period; this results in an improvement of the EB in early lactation. An increased energy status after a short dry period can be further improved by feeding a more glucogenic ration in early lactation.

Effect of dietary net energy concentration on dry matter intake and energy partition in cows in mid‐lactation under heat stress

“…A similar result was also reported by van Knegsel et al . (), who found that dietary energy source (Lipogenic ration group vs. Glucogenic ration group) affects milk fat content (4.38% vs. 4.27%, P = 0.05). Moallem et al .…”

“…However, few studies concerning net energy requirement and energy partitioning of dairy cows under heat stress has not been reported. Recent reports (Huang et al 2014;van Knegsel et al 2014) reflected that dietary energy content may affect energy metabolism of cows. Therefore, the objectives of the present study were to examine the effects of dietary energy concentration of Holstein cows in mid-lactation on milk yield, energy partitioning, efficiency of milk yield, and net energy requirements during medium heat load conditions by the combination of comprehensive experiments, regression analysis, and total collection plus gas exchange methods.…”

Droogstand op maat : verkorten van de droogstand van melkvee: effecten op vervetting en persistentie, uiergezondheid, dierenwelzijn, melkproductie, economie en milieu

“…Materiaal en methode van dit experiment staat uitgebreid beschreven in het wetenschappelijk artikel (Van Knegsel et al, 2014a) en het WHYDRY rapport (Van Knegsel et al, 2014b …”

Aspects of rumen adaptation in dairy cattle : morphological, functional, and gene expression changes of the rumen papillae and changes of the rumen microbiota during the transition period

“…Unfortunately, Albornoz et al (2013) did not report papillae surface area, and the decrease in k a VFA might also be explained by a reduction in epithelial blood flow (discussed below). Finally, considering that the majority of papillae atrophy occurs during the first weeks of the dry period, it is unlikely that a shorter dry period (van Knegsel et al, 2014) than those in the present experiments will prevent such atrophy of the rumen papillae.…”