22. Differences in plasma concentration of insulin-like growth factor-1 between pregnant and non-pregnant dairy cows

Abstract

Insulin-like growth factor-1 (IGF-1) is associated with the reproductive performance of the dairy cow. The association between IGF-1 concentrations in early lactation and interval to first oestrus and conception are widely reported (1). Changes in plasma IGF-1 in mid and late lactation, which may also be associated with advancing pregnancy, have not been reported in the dairy cow. Given the relationship between bovine somatotropin and IGF-1 (2), it would be expected that plasma IGF-1 concentrations would increase as the pregnancy proceeds. The aim of this study is to determine if pregnancy would alter the pattern of changes in plasma IGF-1 concentrations in mid and late lactation. The study was conducted at the Department of Primary Industries, Kyabram, Victoria. All cows were high-producing multiparous Holstein-Friesians, receiving a pasture-based diet. Plasma samples were collected frequently throughout lactation and analysed using the DSL non-extraction IGF-1 ELISA kit. Data were analysed using univariate analysis of variance, with body condition score as a covariate. Data for pregnant cows (n = 24) were analysed relative to actual conception dates for each cow. This was compared to that from non-pregnant cows (n = 10) relative to day 86 of lactation (average conception day of pregnant cows). Average plasma IGF-1 of both pregnant and non-pregnant cows peaked at 103 ng/mL at around week 12 of lactation. It decreased dramatically over the next 5 weeks to 67 ng/mL, and remained relatively constant over the next 10 weeks. Plasma IGF-1 of pregnant cows was numerically higher than that of non-pregnant cows throughout the data collection period. This difference increased after conception and became statistically significant 15 weeks post-conception (P<0.05). At that time, plasma IGF-1 concentrations were 75 ng/mL for pregnant cows and 53 ng/mL for non-pregnant cows. This difference is expected to increase as the pregnancy proceeds.

The role of insulin-like growth factor-1 (IGF-1) in growth and reproduction in female brown house snakes (Lamprophis fuliginosus)

“…5). In viviparous species such as humans, horses, and cattle, IGF-1 has been shown to rise during gestation, and peak during mid-gestation (e.g., Baxter and Martin, 1989;Hess-Dudan et al, 1994;Moyes et al, 2003). Similarly, in one oviparous reptile, the American alligator, Alligator mississippiensis, IGF-1 was shown to peak during mid-gravidity, when luteal activity and plasma progesterone concentrations were also elevated (Guillette et al, 1996), a pattern consistent with recent studies in pigs showing positive effects of IGF-1 on luteal development and progesterone secretion (e.g., Ptak et al, 2003Ptak et al, , 2004Langendijk et al, 2008).…”

Relationship between insulin-like growth factor-1 (IGF-1) concentrations and body trait measurements and climatic factors in prepubertal goat kids

“…IGF-1 is mainly produced in the liver in addition to being produced by the environmental tissues such as the skin, ovary, placenta, breast and bone as autocrine/paracrine (Hashizume et al, 2000;Basturk, 2007). The bioactivity of IGF-1 is achieved by specific insulin-like growth factor binding proteins (IGF-BPs) with high affinity (Obese et al, 2008).…”

“…In addition, it has been reported that IGF-1 concentrations in farm animals are significantly affected by envi-E. Pehlivan: Relationship between IGF-1 concentrations and body trait measurements and climatic factors ronmental factors (Sarko et al, 1994). As a matter of fact, Spicer et al (1994) and Dahl et al (1997) reported that photoperiod and IGF-1 concentration were positively correlated, Richards et al (1995) reported a negative correlation between environmental temperature and IGF-1 concentration, Moyes et al (2003) reported that plasma IGF-1 concentrations decreased when animals were in negative energy balance during the postpartum period, Squires (2003) reported that short-term stress reduced IGF-1 secretion, and Magistrelli et al (2005) reported that energy and protein contents of rations are directly related to the plasma IGF-1 concentration. However, studies regarding the association of IGF-1 concentrations with growth traits and climatic factors have mainly been carried out on farm animal species other than goats.…”