Lactation-induced changes in metabolic status and follicular-fluid metabolomic profile in postpartum dairy cows

Abstract

The aim was to investigate the effect of lactation on the composition of pre-ovulatory follicular fluid (FF). Forty in-calf primiparous heifers and 20 maiden heifers were enrolled. Immediately after calving, half of the cows were dried off while the remainder were milked twice daily. Serum samples were collected twice weekly from two weeks pre- to 84 days postpartum (dpp). FF was analysed by gas chromatography-mass spectrometry. Serum concentrations of non-esterified fatty acids and β-hydroxybutyrate were higher, while glucose, insulin and Insulin-like growth factor 1 (IGF1) concentrations were lower in lactating cows compared with non-lactating cows and heifers (P<0.01). Principal component analysis of FF metabolites revealed a clear separation of the lactating group from both non-lactating cows and heifers. The amino acids tyrosine, phenylalanine and valine and fatty acids heneicosanoic acid and docosahexaenoic acid were all lower in FF from lactating compared with dry cows (P<0.05). FF from lactating cows was higher in aminoadipic acid, α-aminobutyric acid, glycine and serine while histidine, leucine, lysine, methionine and ornithine were all lower than in dry cows and heifers (P<0.05). The ratio of n6:n3 was higher in lactating cows compared with both non-lactating cows and heifers, whereas total n3 polyunsaturated fatty acids, pentadecanoic, linolenic, elaidic and arachidonic acids were all lower in the FF of lactating cows than both non-lactating cows and heifers (P<0.05). In conclusion, lactation induces distinct changes in the overall metabolic status of postpartum lactating dairy cows which are associated with divergent metabolite profiles in FF.

Metabolism-associated genome-wide epigenetic changes in bovine oocytes during early lactation

“…Indeed, 97% of cows experienced a weight loss prior to oocyte collection, with only one cow gaining weight immediately pp that produced negligible amounts of milk and was excluded from further analysis. Therefore, most of the cows in the present study behaved consistently with a negative energy balance as it has been described in other studies 4,20 . Furthermore, cows were selected based on additional criteria including energy balance and metabolic level.…”

Letter to the Editor: About glucose and early embryo development in cows described by Leane et al. (2018)

“…First, the relationship between plasma glucose and uterine luminal fluid glucose levels is not known; Leane et al (2018) detected no difference in uterine luminal fluid glucose levels between the glucose infusion and control (saline infusion) groups. Second, the baseline plasma glucose levels of lactating cows in this study were already at the higher level reported for heifers or nonlactating cows in previous studies (Maillo et al, 2012;Garverick et al, 2013;Forde et al, 2016), suggesting that the glucose infusion that increased levels by ~10 mg/dL in Leane et al (2018) did not really address an insufficiency. Irrespective, it remains quite surprising that glucose infusion did not affect plasma insulin and nonesterified fatty acids, as could be anticipated in late-lactating dairy cows.…”

The effect of exogenous glucose infusion on early embryonic development in lactating dairy cows

“…Green et al (2012) examined the effects of lactation on early postpartum nutrient partitioning and the establishment of pregnancy and reported that increased likelihood of pregnancy after first insemination was associated with greater blood glucose and IGF1 during the first 30 d postpartum (Green et al, 2012). Consistent with these studies, circulating glucose concentrations were greater in heifers (Forde et al, 2016) and postpartum nonlactating dairy cows (Maillo et al, 2012;Forde et al, 2016) than in postpartum lactating cows. Collectively, these studies indicate a clear association between greater glucose concentrations and improved fertility performance.…”

“…Infusion of exogenous glucose elevated blood glucose concentrations by approximately 0.55 mM, a physiologically relevant increase. For example, Maillo et al (2012) and Forde et al (2016) reported blood glucose concentrations of approximately 4 mM for heifers and nonlactating cows and approximately 3.5 mM for lactating cows. This 0.5 mM difference between "fertile" and "less fertile" animals is consistent with the difference between groups in the current study.…”

“…Reduced blood glucose concentrations in early lactation may be detrimental for fertility and embryo survival (Lucy et al, 2013). Circulating glucose concentrations were greater in heifers (Rizos et al, 2010) and postpartum nonlactating dairy cows (Green et al, 2012;Forde et al, 2016) compared with postpartum lactating dairy cows. Greater blood concentrations of glucose at wk 3 and 4 postpartum have been associated with shorter days to pregnancy (Cardoso et al, 2013).…”