Effect of nerve growth factor-β administered at insemination for lactating Holstein dairy cows bred after timed-artificial insemination protocol

Abstract

The objectives of this study were to determine the effects of nerve growth factor-β (NGF), purified from bulls' seminal plasma and administered at the time of artificial insemination (AI), on progesterone post-AI, interferon-stimulated genes (ISG), and pregnancy per AI (P/AI) for lactating Holstein dairy cows enrolled in a timed-AI protocol. We hypothesized that administration of NGF at the time of AI would increase plasma progesterone post-AI, upregulate relative abundance of ISG, and improve P/AI in lactating dairy cows. Holstein cows (n = 557) from a single commercial dairy farm were blocked by parity and randomly assigned to receive an intramuscular injection containing 296 µg of bovine purified NGF at the time of AI, diluted in 2 mL of phosphate-buffered saline (NGF: n = 275), or receive only the 2 mL of phosphate-buffered saline (control: n = 282). Plasma progesterone and corpus luteum size were assessed in a subset of cows (NGF: n = 32; control: n = 36) at d 7, 14, and 19 post-AI. Relative mRNA abundance of ISG (ISG15, MX1, MX2, and RTP4) was assessed in peripheral blood leukocytes on d 19 post-AI. Pregnancy diagnosis was performed at 37 and 65 d post-AI. There was an interaction effect between treatment and parity for plasma progesterone; however, plasma progesterone and ISG did not differ between treatments. There were no effects of NGF for P/AI at 37 d post-AI (NGF = 40.0% vs. control = 41.6%), 65 d post-AI (NGF = 36.0% vs. control = 38.1%), and for pregnancy loss (NGF = 8.4% vs. control = 7.7%). The current study revealed that effects to NGF in lactating Holstein cows were minor and contingent with parity for progesterone, and no improvement in ISG relative abundance and P/AI were observed.

Administration of Beta-Nerve Growth Factor during the Preovulatory Stage Improves Endocrine and Luteal Function in Dairy Heifers

“…Moreover, NGF-treated cows showed a greater concentration of pregnancy-specific protein B (PSPB) at day 24 post-AI, and upregulation of transcripts (i.e., ISG15, MX2) associated with maternal recognition of pregnancy. Conversely, in lactating dairy cows, pregnancy rates did not differ between NGF-treated and non-treated females, 37 days after AI [ 11 ]. Here, the pregnancy rate was numerically higher in those heifers given NGF either at day 9 (46.6%) or day 10 (40.2%) than in non-treated females (36.6%).…”

“…In another recent study [ 10 ], the IM administration of 1 mg of llama NGF, given at the estradiol benzoate (EB)-induced luteinizing hormone (LH) surge, resulted in a significant increase in CL vascular area and higher P4 concentrations on days 6, 9, and 15 after ovulation in dairy heifers. However, in estrus-synchronized lactating Holstein dairy cows, the administration of 296 µg of bull NGF did not affect pregnancy rates, nor embryonic mortality, compared to untreated cows [ 11 ].…”

Improving the efficiency of estrus synchronization in cows

“…Their combined use with GnRH created favorable conditions for the neuro-humoral regulation of sexual processes and ovulation [ 12 , 13 ]. Along with the latter, there is evidence that the combination of phertadinum and surfagon (PGF2α and GnRH, respectively) increases the cows’ fertility by up to 78.3% [ 14 ]. In addition, when the estrous cycle was synchronized with Dinolytic (a synthetic analog of PGF2α) and Fertagyl (a GnRH analog), an increase in cow fertility of up to 80% was observed [ 15 ].…”