Variation in fat mobilization during early lactation differently affects feed intake, body condition, and lipid and glucose metabolism in high-yielding dairy cows

Abstract

Fat mobilization to meet energy requirements during early lactation is inevitable because of insufficient feed intake, but differs greatly among high-yielding dairy cows. Therefore, we studied milk production, feed intake, and body condition as well as metabolic and endocrine changes in high-yielding dairy cows to identify variable strategies in metabolic and endocrine adaptation to overcome postpartum metabolic load attributable to milk production. Cows used in this study varied in fat mobilization around calving, as classified by mean total liver fat concentrations (LFC) postpartum. German Holstein cows (n = 27) were studied from dry off until d 63 postpartum in their third lactation. All cows were fed the same total mixed rations ad libitum during the dry period and lactation. Plasma concentrations of metabolites and hormones were measured in blood samples taken at d 56, 28, 15, and 5 before expected calving and at d 1 and once weekly up to d 63 postpartum. Liver biopsies were taken on d 56 and 15 before calving, and on d 1, 14, 28, and 49 postpartum to measure LFC and glycogen concentrations. Cows were grouped accordingly to mean total LFC on d 1, 14, and 28 in high, medium, and low fat-mobilizing cows. Mean LFC (±SEM) differed among groups and were 351 ± 14, 250 ± 10, and 159 ± 9 mg/g of dry matter for high, medium, and low fat-mobilizing cows, respectively, whereas hepatic glycogen concentrations postpartum were the highest in low fat-mobilizing cows. Cows in the low group showed the highest dry matter intake and the least negative energy balance postpartum, but energy-corrected milk yield was similar among groups. The decrease in body weight postpartum was greatest in high fat-mobilizing cows, but the decrease in backfat thickness was greatest in medium fat-mobilizing cows. Plasma concentrations of nonesterified fatty acids and β-hydroxybutyrate were highest around calving in high fat-mobilizing cows. Plasma triglycerides were highest in the medium group and plasma cholesterol concentrations were lowest in the high group at calving. During early lactation, the decrease in plasma glucose concentrations was greatest in the high group, and plasma insulin concentrations postpartum were highest in the low group. The revised quantitative insulin sensitivity check index values decreased during the transition period and postpartum, and were highest in the medium group. Plasma cortisol concentrations during the transition period and postpartum period and plasma leptin concentrations were highest in the medium group. In conclusion, cows adapted differently to the metabolic load and used variable strategies for homeorhetic regulation of milk production. Differences in fat mobilization were part of these strategies and contributed to the individual adaptation of energy metabolism to milk production.

Corpus luteum development and its morphology after aspiration of a preovulatory follicle is related to size and steroid content of the follicle in dairy cows

“…First, a time period of deep negative energy balance, in which breeding of the animals is not reccomended was chosen for follicle aspiration (1 st follicle aspiration, 37 ± 1.9 days post-partum). Secondly, a time period in which most of the high-yielding cows are in balanced energy metabolism and beginning of breeding is suggested was selected (2nd follicle aspiration, 70 ± 2.2 days post-partum), and thirdly, a time period in which dairy cows return to a positive energy balance and breeding success is known to reach its maximum was investigated (3 rd follicle aspiration, 108 ± 1.8 days post-partum) (Inchaisri et al 2011a,b;Weber et al 2013). As expected, our results showed that a lack of ovarian function is a problem for fertility in dairy herds during the postpartum period within the time period of negative energy balance (Lopez-Gatius et al 2002;Wiltbank et al 2006;Walsh et al 2011).…”

“…For aspiration of the pre-ovulatory follicles three time points were chosen in order to allow investigation of different time periods post-partum, which are marked by different metabolic characteristics (Weber et al 2013). First, a time period of deep negative energy balance, in which breeding of the animals is not reccomended was chosen for follicle aspiration (1 st follicle aspiration, 37 ± 1.9 days post-partum).…”

Physiological adaptations and ovarian cyclicity of Holstein and Montbéliarde cows under two low-input production systems

“…'Backfat thickness' is correlated with total body fat (Schroder and Staufenbiel, 2006), and allowed to differentiate body reserve mobilization among cows that calve with different degree of body fatness (Hammon et al, 2009;Weber et al, 2013). However, it does not take into account internal adipose depots, which may have different dynamics of mobilization during early lactation (Weber et al, 2013). Cows in the current study were at mid (prepartum) to low (postpartum) BCS range, and calved with homogenous levels of fatness, as indicated by BCS.…”

“…However, statistical differences of 'backfat thickness' are due to the greater skin thickness (D0) observed in MONT, which became evident after the depletion of subcutaneous adipose and connective tissues (D1 − D0) postpartum. 'Backfat thickness' is correlated with total body fat (Schroder and Staufenbiel, 2006), and allowed to differentiate body reserve mobilization among cows that calve with different degree of body fatness (Hammon et al, 2009;Weber et al, 2013). However, it does not take into account internal adipose depots, which may have different dynamics of mobilization during early lactation (Weber et al, 2013).…”

Indices of heart rate variability as potential early markers of metabolic stress and compromised regulatory capacity in dried-off high-yielding dairy cows

“…In concert with these energy-saving mechanisms, NEFA plasma concentrations are increased indicating that nutrients are provided by lipolysis (Gross et al, 2011;Weber et al, 2013). In addition, a marked elevation (179%) of the growth hormone-releasing and orexigenic peptide hormone ghrelin (Wertz-Lutz et al, 2006;Bradford and Allen, 2008) has been observed in all cows.…”