Nutritional Factors That Regulate Ovulation of the Dominant Follicle During the First Follicular Wave Postpartum in High-producing Dairy Cows

Abstract

Abstract. During recent decades, milk production per cow has increased drastically due to improved management, nutrition, and genetic selection; however, the reproductive performance of high-producing dairy cows has been declining. One of the factors responsible for this low reproductive performance is negative energy balance (NEB). NEB affects the onset of first ovulation in early postpartum cows. It is generally accepted that early first ovulation positively relates to the resumption of normal ovarian function, first service, and conception rate in dairy cows. Hence, delayed first ovulation has a negative impact on subsequent fertility. The metabolic condition of cows in NEB shifts to catabolic metabolism, which in turn causes increased plasma growth hormone and non-esterified fatty acid concentrations and decreased plasma insulin-like growth factor-1, insulin, and glucose concentrations. On the other hand, plasma β-carotene concentrations decrease throughout the dry period and reach their nadir in about the first week postpartum, and this change reflects energy balance during the peripartum period. β-Carotene plays a role independently of vitamin A in the reproductive performance of dairy cows, and the positive relationship between supplemental β-carotene and reproductive function has been demonstrated in many studies during the past decades. However, β-carotene content in corn silage, which is a popular main feed in high-producing dairy cows, is very low. This review describes nutritional factors related to ovulation during the first follicular wave postpartum in dairy cows. Keywords: β-Carotene, Dairy cow, First follicular wave postpartum, First ovulation, Metabolic hormone (J. Reprod. Dev. 58: [10][11][12][13][14][15][16] 2012) M ilk production per cow has steadily increased due to improved management and genetic selection. In the United States, the milk yield in Holstein cows has increased by approximately 20% in the last 10 years [1]. In Hokkaido, Japan, the milk yield in Holstein cows has increased from 7,114 kg/305 days in 1985 to 9,053 kg/305 days in 2008 (Livestock Improvement Association of Japan). However, reproductive efficiency (e.g., calving interval, services per conception) has declined with the increase in milk production. [5]. Therefore, modern high-producing dairy cows have lower reproductive performance compared to those in the preceding decades.Although nutritional management has improved for high milk production, modern high-producing dairy cows undergo a period of severe negative energy balance (NEB) during early lactation. Because energy output via milk production exceeds energy intake via feed consumption, postpartum dairy cows have to resume normal ovarian cycles under NEB to optimize fertility during the postpartum period. However, recent reports in the scientific literature confirm trends for significantly longer intervals to first ovulation in postpartum dairy cows [6,7].It is generally accepted that cows with early resumption of ovarian function have higher fertility [8][9][1...

Ovarian, metabolic and endocrine indexes in dairy cows with different body condition scores

“…However, our observations seems not to be in concert with other reports on negative interrelationships between plasma NEFA (Zulu et al, 2002;Kawashima et al, 2007Kawashima et al, , 2012Jackson et al, 2011), insulin (Francisco et al, 2003) and ovarian activity. Here we demonstrate the association between the level of endogenous Zn 2+ (but not other microelements) and bovine ovarian functions: BCS2 cows had higher blood Zn 2+ levels, lower ovarian, follicular and corpora albicantia size in comparison with the BCS3 animals, while granulosa cells isolated from the ovaries of the former released more oestradiol than those obtained from the BCS3 group.…”

“…Cows can be a good model to study the link between reproduction, endocrine system, metabolism, and body condition in females. For example, a negative energy balance in post-partum cows causes rapid body weight loss, increased occurrence of metabolic disorders, changes blood levels of glucose, insulin and IGF-I, which are important factors of ovarian functions (Spicer and Echternkamp, 1995;Zulu et al, 2002;Roche et al, 2009;Jackson et al, 2011;Kawashima et al, 2012;Wathes, 2012). A negative energy balance in such cows may restrict the pulsatile release of gonadotropin-releasing hormone, its downstream targets, gonadotropins (FSH and LH), responsiveness of ovarian tissue to gonadotropins and, therefore, adversely affect normal ovarian follicle development, causing follicle atresia (Butler, 2000;Wathes et al, 2007;Hernandez-Medrano et al, 2012).…”

Associations between lipid metabolism and fertility in the dairy cow

“…1). Circulating NEFA concentrations start to increase approximately 2 weeks before calving, peaking at 0-10 days post partum when EB reaches its nadir (Contreras and Sordillo 2011;Kawashima et al 2012). These NEFAs consist mainly of saturated fatty acids, including palmitate (C16:0) and stearate (C18:0), and the monounsaturated fatty acid oleic acid (C18:1n9c; Contreras and Sordillo 2011).…”

“…Non-enzymatic antioxidants include vitamin C (ascorbic acid), vitamin E (a-tocopherol), glutathione and b-carotene (Agarwal et al 2012). b-Carotene acts both as a precursor of vitamin A and independently to enhance host immunological defence mechanisms, but circulating concentrations fall around calving to a minimum at 1-2 weeks post partum (Kawashima et al 2012). Some, but not all, studies have reported that supplementing the diet with bcarotene around this time improves fertility and reduces markers of uterine inflammation (Kaewlamun et al 2011;Kawashima et al 2012).…”

“…b-Carotene acts both as a precursor of vitamin A and independently to enhance host immunological defence mechanisms, but circulating concentrations fall around calving to a minimum at 1-2 weeks post partum (Kawashima et al 2012). Some, but not all, studies have reported that supplementing the diet with bcarotene around this time improves fertility and reduces markers of uterine inflammation (Kaewlamun et al 2011;Kawashima et al 2012). Concentrations of vitamin E, another fat-soluble vitamin with antioxidant properties, may also be inadequate around calving, with a meta-analysis showing that vitamin E supplementation could reduce the risk of retained fetal membranes (Bourne et al 2007).…”