Effect of peripartum dietary energy supplementation on thyroid hormones, insulin-like growth factor-I and its binding proteins in early lactation dairy cows

• Published in: Acta veterinaria (Beograd) Vol. 62; no. 4; pp. 403 - 419
• Main Authors: Kirovski, D., Faculty of Veterinary Medicine, Belgrade (Serbia), Sladojević, Ž., Veterinary Station Veterina System Sladojević, Gradiška, Republic of Srpska (Bosnia and Herzegovina), Stojić, V., Faculty of Veterinary Medicine, Belgrade (Serbia), Vujanac, I., Faculty of Veterinary Medicine, Belgrade (Serbia), Lazarević, M., Faculty of Veterinary Medicine, Belgrade (Serbia), Radovanović, A., Faculty of Veterinary Medicine, Belgrade (Serbia), Savić, Đ., Faculty of Agriculture, Banja Luka (Bosnia and Herzegovina), Nedić, O., Institute for the Application of Nuclear Energy – INEP, Belgrade (Serbia)
• Format: Journal Article
• Language: English
• Published: Sciendo 2012
• Subjects: COMPLAMENT ALIMENTAIRE POUR ANIMAUX; DAIRY COWS; energy supplementation; FACTEUR DE CROISSANCE IGF; FACTOR DE CRECIMIENTO IGF; FEED SUPPLEMENTS; HORMONAS DE LA TIROIDE; HORMONE THYROADIENNE; http://www.fao.org/aos/agrovoc#c_26767; http://www.fao.org/aos/agrovoc#c_2837; http://www.fao.org/aos/agrovoc#c_29378; http://www.fao.org/aos/agrovoc#c_34028; http://www.fao.org/aos/agrovoc#c_7754; IGF-I; IGFBPs; INSULIN-LIKE GROWTH FACTOR; PARIODE PARINATALE; PERAODO PERINATAL; PERINATAL PERIOD; SUPLEMENTOS DE PIENSOS; THYROID HORMONES; VACAS LECHERAS; VACHE LAITIARE
• ISSN: 0567-8315; 1820-7448
• DOI: 10.2298/AVB1204403K

The objective of this study was to examine the effect of dietary energy supplementation on hormones that are considered to be the main signals of a shift in energy balance around parturition. Sixty dry cows, 15 days before calving, were chosen and divided into two eaqual groups: control and experimental (GLY). Both groups were fed a standard ration balanced in accordance to the stage of the productivereproductive cycle. Additionally, each cow in the GLY group was given glycerol based dietary energy supplementation (250 mL daily during the dry and 300 mL daily during the lactation period), which provided additional 9.30 MJ NEL during the dry and 13.95 MJ NEL during the early lactation period. Milk production was measured on days 30 and 60 of lactation and milk production was significantly higher in GLY compared to control group at day 60 of lactation (p is less than 0.05). Service period and insemination index were used as reproductive outcome parameters. Average service period in the control group was significantly longer than in the GLY group (p is less than 0.05). Average insemination index in the control group was not significantly different than the index obtained for the GLY group. Blood samples were taken before the begining of the experiment (15 days before parturition), and at days 7, 30 and 60 of lactation. Concentrations of thyroid hormones, IGF-I, relative abundance of IGFBP-2, IGFBP-3 and IGFBP-4, concentrations of total protein and albumin in the blood were measured. Results showed that at days 7 and 30 after parturition, T4 concentrations were significantly higher (p is less than 0.001, respectively) in GLY than in the control group, while T3 concentrations were significantly higher in GLY group only at day 7 after parturition (p is less than 0.001). IGF-I concentrations and IGFBP-3 abundance were significantly higher in the GLY compared to the control group in all three examined postpartum periods. IGFBP-2 and IGFBP-4 concentrations were higher in GLY compared to the control group in all three examined postpartum periods, but the difference was significant only on day 60 after parturition (p is less than 0.01, respectively). Concentrations of total protein and albumin were significantly higher in GLY compared to the control group in all three examined periods after parturition. Based on these results it can be concluded that peripartum dietary energy supplementation prevent cows' exposure to severe negative energy balance, preserves synthetic activity of hepatocytes and consequently has a positive impact on milk production and reproductive performances in dairy cows.