Effect of dry period diets varying in energy density on health and performance of periparturient dairy cows: a study of dry matter intake, lactation performance, fertility, blood parameters and liver condition

Effect of feed with different energy levels in the close-up dry period (3-0 weeks prepartum) on different production and health parameters were examined around parturition of 30 Icelandic cows and heifers in individual tie stalls. Dry matter intake (DMI) was registered, lactation performance, i.e. milk yield and milk composition were measured and analyzed, ovarian activity was estimated by measuring concentration of the hormone progesterone in milk. The metabolic status of the cows was monitored by collection and analysis of liver biopsies and blood samples. Glucose, BHB (β- hydroxybutyrate), NEFA (Non-esteriffied fatty acids), GLDH (Glutamate dehydrogenase), AST (Aspartat aminotransferase), GGT (Gamma glutamyl transferase), ICDH (Isocitrate dehydrogenase) were analyzed from blood and liver fat was estimated under a microscope. Ketolac® test was used to estimate the level of BHB in milk. DMI prepartum was higher for cows receiving higher energy levels in feed but they did not maintain significantly higher DMI into the lactation, increased energy prepartum gave lower fat- and urea concentration in milk. Parity had the greatest effects on ECM, protein and lactose in milk. Treatments did not significantly affect ovarian activity, ketone bodies in milk as estimated by Ketolac test or liver fat infiltration. Glucose concentration in blood increased significantly with increased energy level, there was also a significant effect of periods and parity. Treatment did not affect BHB or NEFA concentration significantly. BHB concentration was highest in the first three weeks postpartum and heifers had lower BHB concentration than older cows. NEFA concentration was highest around parturition. Treatments affected GLDH enzyme concentration significantly, GLDH increased with increased energy level in diet. Treatments did not affect AST, GGT or ICDH significantly.

Author dc:creator

• Berglind Ósk Óðinsdóttir 1980-

Contributors dc:contributor

• Landbúnaðarháskóli Íslands

• Burður
• Fóðrun
• Mjólk
• Efnainnihald
• Blóðrannsóknir

Language dc:language.iso

en

Handle dc:identifier.uri

http://hdl.handle.net/1946/7470

OAI identifier oai:identifier

oai:skemman.is:1946/7470