Biology Reference
In-Depth Information
Chapter 4
Effect of Dry Period Length on NEFA and IGF-I
Plasma Concentrations and Postpartum Ovarian
Activity Resumption in Dairy Cows
M. Probo, A. Comin, A. Agazzi, I. De Amicis, A. Prandi, and F. Cairoli
Abstract The current study was carried out to examine the effects of dry period
duration on NEFA and IGF-I plasma concentrations and postpartum ovarian activ-
ity resumption in dairy cows. Twenty-five pregnant Friesian cows (second and third
lactation) were randomly assigned to one (standard dry period, 9 weeks, group C,
n
13) treatments. Blood
samples for NEFA and IGF-I analyses were collected once a week during the last
5 weeks prepartum and the first 14 weeks of lactation. Milk whey collection (twice/
week) for progesterone analysis began 2 weeks after parturition and was used
to detect ovarian activity resumption (at least three consecutive samples with
P4
12) of two (short dry period, 5 weeks, group T,
n
¼
¼
300 pg/mL). The data obtained were analyzed by ANOVA for repeated
data (mixed) and GLM of the SAS statistical package. Short dry periods reduced
milk production (26.55 vs. 27.55 kg/day;
P
0.01), without modifying milk
quality. The mean interval from calving to first postpartum cycle was shorter in
group T than in group C (34.5 vs. 46.9 days,
P
0.01). No differences were found
in NEFA plasma concentrations between groups either before or after calving,
while IGF-I circulating concentrations were higher in group T than in group C
during both the dry period and the first 14 weeks of lactation (
P
0.01). In
conclusion, the reduction in the dry period had a positive impact on metabolic
balance and time of postpartum resumption of ovarian activity.
M. Probo (
*
) • F. Cairoli
Dipartimento di Scienze Cliniche Veterinarie, Universit
´
degli Studi di Milano, Milano, Italy
e-mail:
monica.probo@unimi.it
A. Comin • A. Prandi
Dipartimento di Scienze degli Alimenti, University of Udine, Udine, Italy
A. Agazzi
Dipartimento di Scienze e Tecnologie Veterinarie per la Sicurezza Alimentare, Universit´ degli
Studi di Milano, Milano, Italy
I. De Amicis
Dipartimento di Scienze Cliniche Veterinarie, University of Teramo, Teramo, Italy
