Effects of Feeding Intensity During the Dry Period. 2. Metabolic and Hormonal Responses

Abstract

The metabolic response to different feeding levels during the dry period was studied in 24 multiparous dairy cows of the Swedish Red and White breed. The cows represented two lines, selected for high or low milk fat percentage, at the same amount of energy produced in milk. The cows were fed one of three different amounts of the same total mixed diet during the dry period, starting 8 wk prior to the expected parturition. The rations provided 71, 106, or 177 MJ metabolizable energy per day. After parturition the cows were offered another total mixed diet ad libitum for the first 12 wk of lactation. Glucose challenges were performed 3 wk prior to and 3 wk after parturition. Prepartum the glucose clearance rate was related to feeding level. Insulin response to the glucose challenge was reduced during the postpartum period, compared to the prepartum period. During about 6 wk prepartum, the insulin level in plasma was related to feeding level. At the sampling 3 wk prior to parturition the plasma level of leptin also was related to the feeding level. After parturition both leptin and insulin were reduced. In early lactation plasma leptin concentration was not related to adiposity as reflected by body condition scoring. It was suggested that lactation as such affected the leptin concentration in plasma.

Energy intake in late gestation affects blood metabolites in early lactation independently of milk production in dairy cows

“…The higher glucose and lower NEFA concentrations during the last 3 weeks of gestation (Table 2) in cows offered the H diet suggest that these cows were mobilising less body fat than cows offered diet L, which was attributable to the differences in energy intake. A similar effect has also been observed during the last few weeks of gestation in other experiments (Grum et al, 1996;Holtenius et al, 2003;Rabelo et al, 2005;Douglas et al, 2006).…”

“…Post-calving blood concentrations of NEFA also indicated that cows on treatment HL mobilised more body reserves than cows on the other treatments. The higher NEFA concentrations, post-calving, in cows offered diet H pre-calving were most likely because of the higher BCS of these cows at calving and thus their tendency to mobilise more in the first weeks of lactation ( Figure 2); this is in accordance with other studies where a difference in BCS was obtained during the last part of gestation Holtenius et al, 2003). The higher BHB level and lower glucose level post-calving in cows on treatment HL was probably a consequence of their higher NEFA level that was partly oxidised to ketone bodies in the liver.…”

“…The higher BHB level and lower glucose level post-calving in cows on treatment HL was probably a consequence of their higher NEFA level that was partly oxidised to ketone bodies in the liver. A higher glucose level post-calving because of a lower BCS at calving has also been reported by Holtenius et al (2003) 1 to 4 weeks postcalving, whereas other studies have found no effect Jones and Garnsworthy, 1988).…”

“…These two feeding strategies have been compared in a number of experiments but have often failed to show significant effects on metabolic indicators of fat and liver -E-mail: nicolas.friggens@agroparistech.dk metabolism post-calving. Offering a high-energy-density diet (H) in the dry period has, in some studies, increased non-esterified fatty acids (NEFA) post-calving, compared to a low-energy-density diet (L) (Rukkwamsuk et al, 1998;Holtenius et al, 2003), but most studies have found no effect (Minor et al, 1998;Tesfa et al, 1999;Holcomb et al, 2001;Doepel et al, 2002;Rabelo et al, 2005;Dann et al, 2006). Different results have also been reported for liver lipid/triacylglycerol (TAG) where one study has shown a decreased content post-calving for cows offered an H diet in the dry period compared to an L diet (Doepel et al, 2002), others the opposite (Rukkwamsuk et al, 1998;Douglas et al, 2006), whereas others again have found no effect (Grum et al, 1996;Tesfa et al, 1999;Rabelo et al, 2005).…”

Effects of live weight adjusted feeding strategy on plasma indicators of energy balance in Holstein cows managed for extended lactation

“…As previously found by Holtenius and Holtenius (2007), plasma components vary over the periods but not the RQUICKI index, so it seems a good indicator to identify changes in insulin sensitivity for these cows. Moreover, we found a correlation between BCS and RQUICKI, in accordance with Holtenius et al (2003) suggesting that cows with high BCS should have a lower RQUICKI and be more insulin resistant than the thin cows (Holtenius et al, 2003). Our RQUICKI values were not affected by the period of the lactation.…”