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- Title
Hot season and BCS affect leptin secretion of periparturient dairy cows.
- Authors
Bernabucci, U.; Lacetera, N.; Basiricò, L.; Ronchi, B.; Morera, P.; Seren, E.; Nardone, A.
- Abstract
The study was carried out to ascertain the effects of the hot season and BCS on leptin secretion in transition dairy cows. Twenty-four Holstein cows were utilized in the study. Twelve cows (SP cows) gave birth in spring (28 March to 30 April, 2003). The remaining 12 cows (SU cows) gave birth in summer (15 June to 2 July, 2003). The two groups were balanced for parity and body condition score (BCS), and were fed the same rations. The 24 cows were selected on a BCS basis: cows with BCS <2.5, BCS from 2.6 to 3.5, and BCS >3.5 were assigned to low (LBCS), medium (MBCS), and high (HBCS) BCS groups, respectively. From -32 to 38 d relative to calving BCS was registered, and blood samples were taken weekly. Plasma leptin was determined. Data were analyzed using the Mixed Procedure of SAS. During SP, either the day (9-20 h) or the night (21-8 h) temperature-humidity index (THI) was below the upper critical THI (72). During SU, the mean daily THI values were 79.5±2.9 during the day, and 70.1±4.7 during the night. Furthermore, during SU, three heat waves occurred. The first heat wave lasted 5, the second 6, and the third 15 d. BCS began to decrease approximately 15 d before calving in SU cows, whereas in SP cows BCS started to decline after calving. Plasma leptin decreased (P<0.05) approaching to calving both in SU and SP cows. The HBCS cows showed higher (P<0.05) BCS reduction than LBCS and MBCS groups both during SU and SP. Compared with SP cows, plasma leptin was higher (P<0.01) in SU cows. In SU cows only, either before or after calving, a negative relationship (P<0.01) was found between plasma leptin and BCS, and HBCS cows had lower (P<0.001) plasma leptin compared with their LBCS and MBCS counterparts. On the contrary, SP-HBCS cows had higher (P<0.01) plasma leptin when compared with their LBCS and MBCS counterparts. Results reported herein, indicate that hot season is responsible for increased leptin secretion, and for changes into the relationships between body condition and leptin secretion in periparturient dairy cows.
- Subjects
COWS; SECRETION; LACTATION in cattle; LEPTIN; DAIRY farms; BLOOD sampling
- Publication
Journal of Animal Science, 2006, Vol 84, p348
- ISSN
0021-8812
- Publication type
Article