Insulin-Like Growth Factor-I in Dairy Cows: Relationships Among Energy Balance, Body Condition, Ovarian Activity, and Estrous Behavior

Abstract

The objective was to determine relationships among concentrations of insulin-like growth factor-I in serum, energy balance, body condition, and ovarian activity during early lactation. From 0 to 12 wk postpartum, 11 pluriparous Holstein cows were individually fed a total mixed diet and bled twice weekly for quantification of insulin-like growth factor-I and progesterone. Estrous behavior was monitored twice daily and body condition scores were recorded weekly. Individual feed intake and milk production were recorded daily and milk composition and BW were measured weekly. Cows with positive (3.43 Mcal/d; n = 5) energy balance during the first 12 wk postpartum had greater concentrations of insulin-like growth factor-I in serum and greater luteal-phase progesterone secretion than in cows with negative (-1.69 Mcal/d; n = 6) energy balance. Interval to first ovulation or first estrus did not differ between cows with positive versus negative energy balance. Correlation coefficients among weekly averages revealed positive correlations between energy balance and serum progesterone, and energy balance and serum insulin-like growth factor-I. Body condition scores were not correlated with energy balance or serum insulin-like growth factor-I. We conclude that reduced luteal activity that accompanies negative energy balance may be associated with reduced concentrations of insulin-like growth factor-I in serum.

Insulin-Like Growth Factor-I as a Possible Hormonal Mediator of Nutritional Regulation of Reproduction in Cattle

“…Preliminary studies in our laboratory have also found a positive correlation between IGF-I and estrogen in serum of early postpartum dairy cows. Improvement in energy balance not only leads to an increase in secretion of IGF-I as previously discussed, but also progesterone during the first and second estrous cycles postpartum [81,83,86]. Beam and Butler [8,9] also found that plasma IGF-I levels were 40-50% higher during the first 2 weeks postpartum in dairy cows when the first dominant follicle (DF) ovulated compared with those with non-ovulatory follicles.…”

“…However, in a later study McGuire et al [57] reported for the first time that in two days of feed deprivation, circulating concentrations of IGF-I reduced by 50% in lactating cows. Spicer et al [83] reported that short-term fasting in heifers decreased plasma IGF-I, and Lucy et al [55] found that cows fed low energy diets had lower plasma IGF-I. In suckled and/or non-pregnant beef cows, feed restriction resulted in a marked depression in serum concentrations of IGF-I, whereas insulin and glucose were only depressed slightly [72,74].…”

“…lactating dairy cows with positive energy balance have greater circulating concentrations of IGF-I than those in NEB [9,10,34]. Spicer et al [83] observed that during the first 12 weeks, postpartum cows in NEB had low concentrations of IGF-I in circulation. An improvement of energy balance (less severe NEB) was associated with an increase in serum concentration of IGF-I [13].…”

Validation of a new method of visual oestrus detection on the farm

“…Milk yield and associated energy requirements are often mentioned as cause for vague oestrus expression. However, the results of the studies that have been reported so far are inconclusive (10,16,23,25,26). Environmental factors are the third group of factors affecting oestrus detection.…”

“…10, might be the reason for the differences. Spicer et al (23) and Villa-Godoy et al (26) reported that the expression of oestrus was not affected in second and third…”