Reproductive performance of heifers induced to oestrous asynchrony by suprabasal plasma progesterone levels |
| |
| Institution: | 1. Department of Obstetrics and Gynaecology, Swedish University of Agricultural Sciences, S-75007 Uppsala, Sweden;2. Department of Clinical Chemistry, Swedish University of Agricultural Sciences, S-75007 Uppsala, Sweden;3. Swedish Association for Livestock Breeding and Production, S-63184, Eskilstuna, Sweden;1. CIISA, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal;2. Department of Animal Science, Coimbra College of Agriculture, Coimbra, Portugal;3. Department of Reproductive Immunology and Pathology, Institute of Animal Reproduction and Food Research of PAS, Olsztyn, Poland;1. Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan, Merelbeke, 9820, Belgium;2. Laboratory of Veterinary Physiology and Biochemistry, Department of Veterinary Sciences, University of Antwerp, Universiteitsplein, Wilrijk, 2610, Belgium;3. Laboratory for Animal Nutrition and Animal Product Quality, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Coupure Links, Ghent, 9000, Belgium;4. Department of Pharmacology, Toxicology and Biochemistry, Faculty of Veterinary Medicine, Ghent University, Salisburylaan, Merelbeke, 9820, Belgium;5. Animal Sciences Unit, Flanders Research Institute for Agriculture, Fisheries and Food (ILVO), Scheldeweg, Melle, 9090, Belgium;1. Department of Production Animal Studies, Faculty of Veterinary Science, University of Pretoria, South Africa;2. Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, South Africa;3. Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, South Africa;4. Pferdezentrum Bad Saarow, Clinic for Horses, Free University, Bad Saarow, Germany;5. Department of Companion Animal Studies, Faculty of Veterinary Science, University of Pretoria, South Africa;1. Departament of Animal Reprodution, FMVZ-USP, Pirassununga, SP, Brazil;2. Department of Animal Sciences, University of Florida, Gainesville, United States;1. Center for Quantitative Genetics and Genomics, Department of Molecular Biology and Genetics, Aarhus University, DK-8830 Tjele, Denmark;2. Animal Genetics and Integrative Biology, UMR 1313 GABI, INRA, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France |
| |
| Abstract: | Suprabasal progesterone concentrations around oestrus have induced disturbances in oestrous behaviour and ovulation. To determine whether fertility in such an altered oestrus can be maintained at normal levels with additional inseminations (AI) until ovulation, fertility was compared in heifers (n = 11) inseminated in normal oestrous cycles and thereafter in cycles in which the animals were treated with progesterone in order to create suprabasal concentrations after luteolysis. The treatment consisted of silicone implants containing 10.6 mg kg?1 of progesterone inserted subcutaneously on Day 8 of the oestrous cycle (day of ovulation designated Day 0) and removed on Day 25. Both in control oestrous cycles and oestrous cycles under progesterone treatment, growth of the ovulatory follicle and ovulation were determined by frequent ultrasound scanning. Blood was collected frequently for further analysis of progesterone, oestradiol-17β and luteinising hormone (LH). Insemination was performed 12 h after onset of standing oestrus. if ovulation did not occur 24 h after AI, heifers were inseminated again until ovulation. Pregnancy was diagnosed by ultrasound 25 days after ovulation.In control oestrous cycles, plasma progesterone decreased to 0.3 ± 0.3 nmol 1?1. Duration of oestrus was 22.9 ± 2.0 h, the interval from onset of oestrus to ovulation was 32.4 ± 2.3 h and the interval from LH peak to ovulation was 28.6 ± 1.4 h. The interovulatory interval was 20.7 ± 0.6 days. In oestrous cycles in treated heifers, progesterone decreased to 1.0 ± 0.3 nmol l?1 (P > 0.10) and the interovulatory interval was prolonged to 23.5 ± 1.0 days (P < 0.05). Standing oestrus lasted 47.2 ± 12.0 h (P = 0.09, n = 7). The interval from the onset of oestrus to ovulation was 59.4 ± 13.0 h (P = 0.08) and the interval from LH peak to ovulation 25.8 ± 1.3 h (P > 0.10). The prolonged oestrus was associated with increased (P < 0.05) growth of the ovulatory follicle and higher (P < 0.05) release of oestradiol-17β. Conception rates were 90% and 46% (P < 0.05), and the numbers of AI per heifer were 1.1 ± 0.1 and 3.4 ± 0.6 (P < 0.01) for control oestrous cycles and after treatment, respectively.The induction of suprabasal concentrations of progesterone caused asynchronies similar to those observed in cases of repeat breeding. The repeated AI did not maintain fertility at normal levels. It is suggested that the extended growth of the ovulatory follicle may cause impaired oocyte maturation or it may alter the maternal milieu owing to the prolonged release of oestradiol. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
