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Effects of lasalocid on circulating concentrations of leptin and insulin-like growth factor-I and reproductive performance of postpartum Brahman cows1
- Source :
- Journal of Animal Science. 81:1363-1370
- Publication Year :
- 2003
- Publisher :
- Oxford University Press (OUP), 2003.
-
Abstract
- Objectives were to determine effects of lasalocid on reproductive performance and serum concentrations of leptin and IGF-I, and to correlate concentrations of leptin and IGF-I with reproductive performance of beef cows. Forty-one purebred, multiparous Brahman cows were blocked to control (C; n = 20) or lasalocid (L; n = 21) treatments by BW, BCS, and predicted calving date. Treatment began 21 d before expected calving. Cows were each fed 1.4 kg daily of an 11:1 corn:soybean meal supplement, with the L group receiving 200 mg of lasalocid/cow daily. Cows and calves were weighed, and cow BCS was assessed at calving and at 28-d intervals thereafter. Blood samples were collected weekly precalving, at parturition, and twice weekly thereafter. Sterile marker bulls were maintained with cows for estrous detection. Six days after estrus, ovaries were evaluated for corpus luteum formation, and blood samples from d 6, 7, and 8 after estrus were collected. Serum samples were assayed for progesterone (P4), IGF-I, and leptin concentration. Progesterone concentrations > 1 ng/mL were considered indicative of a functional corpus luteum. Treatment ended after completion of a normal estrous cycle, and cows removed from treatment were placed with a fertile bull equipped with a chinball marker. There were no treatment differences in calving date, calf sex, cow BW, BCS, calf BW, calf ADG, or in serum concentrations of P4, IGF-I, or leptin. Prepartum cow ADG was increased (P 0.18) for serum IGF-I concentrations. At calving, leptin was positively correlated with IGF-I (P < 0.04; r = 0.32), BCS (P < 0.06; r = 0.29), and cow BW (P < 0.02; r = 0.36), and was negatively correlated with PPI (P < 0.06; r = -0.29). These results provide evidence that feeding an ionophore before calving and during the postpartum period may increase the number of cows that rebreed to maintain a yearly calving interval. Cows with higher concentrations of leptin postpartum may exhibit shorter PPI.
- Subjects :
- Estrous cycle
medicine.medical_specialty
Leptin
Brahman
food and beverages
Ice calving
General Medicine
Beef cattle
Biology
chemistry.chemical_compound
medicine.anatomical_structure
Animal science
Endocrinology
chemistry
Internal medicine
Genetics
medicine
Animal Science and Zoology
Corpus luteum
Postpartum period
Food Science
Lasalocid
Subjects
Details
- ISSN :
- 15253163 and 00218812
- Volume :
- 81
- Database :
- OpenAIRE
- Journal :
- Journal of Animal Science
- Accession number :
- edsair.doi...........c4f3a87230040ef52acd6c090e0cac9c
- Full Text :
- https://doi.org/10.2527/2003.8161363x