title: Effects of acute feed restriction combined with targeted use of increasing luteinizing hormone content of follicle-stimulating hormone preparations on ovarian superstimulation, fertilization, and embryo quality in lactating dairy cows.
abstract: Multiple metabolic and hormonal factors can affect the success of protocols for ovarian superstimulation. In this study, the effect of acute feed restriction and increased LH content in the superstimulatory FSH preparation on numbers of ovulations, fertilization, and embryo quality in lactating dairy cows was evaluated. Two experiments were performed using a Latin square design with treatments arranged as a 2 × 2 factorial: feed restriction (FR; 25% reduction in dry matter intake) compared with ad libitum (AL) feeding, combined with high (H) versus low (L) LH in the last 4 injections of the superstimulatory protocol. As expected, FR decreased circulating insulin concentrations (26.7 vs. 46.0 μU/mL). Two analyses were performed: one that evaluated the complete Latin square in experiment 2 and a second that evaluated only the first periods of experiments 1 and 2. For both analyses, follicle numbers, ovulation rates, and corpora lutea on d 7 were not different. In the first period analysis of experiments 1 and 2, we observed an interaction between feed allowance and amount of LH on fertilization rates, percentage of embryos or oocytes that were quality 1 and 2 embryos, and number of embryos or oocytes that were degenerate. Fertilization rates were greater for the AL-L (89.4%) and FR-H (80.1%) treatments compared with the AL-H (47.9%) and FR-L (59.9%) treatments. Similarly, the proportion of total embryos or oocytes designated as quality 1 and 2 embryos was greater for AL-L (76.7%) and FR-H (73.4%) treatments compared with AL-H (35.6%) and FR-L (47.3%) treatments. In addition, the number of degenerate embryos was decreased for AL-L (1.3) and FR-H (0.4) treatments compared with the AL-H (2.6) and FR-L (2.3) treatments. Thus, cows with either too low (FR-L) or too high (AL-H) insulin and LH stimulation had lesser embryo production after superstimulation because of reduced fertilization rate and increased percentage of degenerate embryos. Therefore, interaction of the gonadotropin content of the superstimulatory preparation with the nutritional program of the donor cow needs to be considered to optimize success of ovarian superstimulatory protocols.
authors.affiliation: Department of Dairy Science, University of Wisconsin-Madison, 1675 Observatory Dr., Madison 53706.
authors.forename: R W
authors.initials: RW
authors.lastname: Bender
authors.affiliation: Department of Dairy Science, University of Wisconsin-Madison, 1675 Observatory Dr., Madison 53706.
authors.forename: K S
authors.initials: KS
authors.lastname: Hackbart
authors.affiliation: Department of Dairy Science, University of Wisconsin-Madison, 1675 Observatory Dr., Madison 53706.
authors.forename: A R
authors.initials: AR
authors.lastname: Dresch
authors.affiliation: Department of Dairy Science, University of Wisconsin-Madison, 1675 Observatory Dr., Madison 53706.
authors.forename: P D
authors.initials: PD
authors.lastname: Carvalho
authors.affiliation: Department of Dairy Science, University of Wisconsin-Madison, 1675 Observatory Dr., Madison 53706.
authors.forename: L M
authors.initials: LM
authors.lastname: Vieira
authors.affiliation: Department of Dairy Science, University of Wisconsin-Madison, 1675 Observatory Dr., Madison 53706.
authors.forename: P M
authors.initials: PM
authors.lastname: Crump
authors.affiliation: Department of Dairy Science, University of Wisconsin-Madison, 1675 Observatory Dr., Madison 53706.
authors.forename: J N
authors.initials: JN
authors.lastname: Guenther
authors.affiliation: Department of Dairy Science, University of Wisconsin-Madison, 1675 Observatory Dr., Madison 53706.
authors.forename: P M
authors.initials: PM
authors.lastname: Fricke
authors.affiliation: Department of Dairy Science, University of Wisconsin-Madison, 1675 Observatory Dr., Madison 53706.
authors.forename: R D
authors.initials: RD
authors.lastname: Shaver
authors.affiliation: Department of Dairy Science, University of Wisconsin-Madison, 1675 Observatory Dr., Madison 53706.
authors.forename: D K
authors.initials: DK
authors.lastname: Combs
authors.affiliation: Department of Dairy Science, University of Wisconsin-Madison, 1675 Observatory Dr., Madison 53706. Electronic address: wiltbank@wisc.edu.
authors.forename: M C
authors.initials: MC
authors.lastname: Wiltbank
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002417:Cattle / Q000502:physiology*; D005260:Female; D005306:Fertilization / Q000187:drug effects*; D005640:Follicle Stimulating Hormone / Q000494:pharmacology*; D005508:Food Deprivation; D007774:Lactation; D007986:Luteinizing Hormone / Q000494:pharmacology*; D009865:Oocytes / Q000502:physiology; D006080:Ovarian Follicle / Q000502:physiology*; D010060:Ovulation / Q000187:drug effects*; D011897:Random Allocation
chemical_list: D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone
keywords: dairy cattle; feed restriction; luteinizing hormone; superstimulation