The impact of cow nutrient status during the second and third trimesters on age at puberty, antral follicle count, and fertility of daughters

Abstract

a b s t r a c tFluctuating feed resources to beef cows across the production cycle is a proven method for decreasing input costs; however, limiting nutrients during late gestation have been demonstrated to decrease ovarian follicle numbers in female offspring in some studies. We hypothesize that limiting nutrients to mature ( Z3 yr) crossbred beef cows during the second and third trimesters would result in daughters that would have decreased follicle numbers detectable by ultrasonography as yearlings. Over four breeding seasons, pregnant beef cows (n ¼ 397) were assigned to either Low (L), Moderate (M) or High (H) nutrient intake during the second or third trimester, resulting in four dietary treatment groups (L-H, L-L, M-H, and M-M). Heifers (n ¼416) born to these cows were weighed at weaning and moved to a dry lot where they were monitored for behavioral estrus with the aid of heat detection patches. Two weeks before their first breeding season, heifers were submitted for ultrasonographic examination of their ovaries to determine antral follicle numbers. Heifers were placed with bulls for 60 d and pregnancy status was determined 45 d after the bulls were removed. Growth and reproductive traits were analyzed using the MIXED Procedure of SAS with maternal diet and year as fixed effects. Maternal dietary intake did not affect heifer growth rates, age at puberty, or antral follicle counts (PZ 0.40). However, an increased proportion of the heifers born to dams fed a high nutrient diet during the third trimester (L-H or M-H) calved in the first 21 d of their first calving season (P¼ 0.004). Antral follicle counts detectable by ultrasonography at yearling pre-breeding examination were greater in heifers that calved during the first 21 d of their first calving season (P ¼ 0.02); however, these heifers did not differ in age at puberty (P ¼ 0.60). From this study, we conclude that: (1) limiting nutrient intake during late gestation in mature ( Z3 yr) beef cows does not influence the ovarian reserve or reproductive performance of daughters; (2) increasing maternal nutrient intake during ☆ Names are necessary to report factually on available data; however, the USDA neither guarantees nor warrants the standard of the product, and the use of names by the USDA implies no approval of the product to the exclusion of others that may also be suitable.n Corresponding author. This article is a U.S. government work, and is not subject to copyright in the United States.the third trimester can improve the first service conception rates of daughters; and (3) pre-breeding ultrasonography to determine antral follicle counts is a good indicator of fertility for choosing replacement heifers. Published by Elsevier B.V.

Feeding distiller's grains as an energy source to gestating and lactating beef heifers: Impact on female progeny growth, puberty attainment, and reproductive processes1

“…Previous studies (Sullivan et al, 2009;Mossa et al, 2010;Echternkamp et al, 2012) have reported that nutritional manipulation during early gestation in first-parity dams can impact ovarian antral follicle count in their female progeny. In contrast, however, Cushman et al (2014) reported no differences in antral follicle count of heifer progeny of mature cows that were fed 75, 100, or 125% of NRC maintenance requirements during the last 2 trimesters of pregnancy. Although progeny in the current study were from first-parity dams and only prepubertal antral follicle counts were obtained, results from the current dataset is consistent with those of Cushman et al (2014), who reported no differences in antral follicle counts obtained in progeny at 14 mo of age.…”

“…In contrast, however, Cushman et al (2014) reported no differences in antral follicle count of heifer progeny of mature cows that were fed 75, 100, or 125% of NRC maintenance requirements during the last 2 trimesters of pregnancy. Although progeny in the current study were from first-parity dams and only prepubertal antral follicle counts were obtained, results from the current dataset is consistent with those of Cushman et al (2014), who reported no differences in antral follicle counts obtained in progeny at 14 mo of age. Moreover, in the current study, heifer progeny from DG-treated dams were significantly heavier at birth (Gunn et al, 2014b); however, no differences were observed in antral follicle counts between treatments, and birth BW and antral follicle count were not correlated.…”

“…Previous studies have reported that altering maternal diet during gestation can affect the reproductive development of female progeny in both beef (Mossa et al, 2010;Sullivan et al, 2009;Echternkamp et al, 2012) and sheep (Da Silva et al, 2002, 2003 and ultimately impact fertility of female progeny in beef cattle (Martin et al, 2007;Cushman et al, 2014). However, reports to date have been inconsistent, and to our knowledge, none have reported on the effects of feeding DDGS during both late gestation and early lactation.…”

“…If so, it is feasible that maternal treatment in the current study indirectly regulated progeny puberty attainment through an alteration in growth pattern and not directly through an alteration of the hypothalamic-pituitary-ovarian axis. Cushman et al (2014) reported no differences in age a puberty for heifers progeny from mature cows fed differing amounts of energy during the last 2 trimesters of gestation, and Martin et al (2007) reported that there was no difference in age at puberty of heifer progeny resulting from dams supplemented with 0.45 kg/d of a protein supplement during late gestation compared to nonsupplemented dams. However, dams in the current study were fed similar amounts of energy, with CP in the DG treatment drastically exceeding NRC requirements during the last trimester of gestation through mid lactation.…”

Effects of excess metabolizable protein on ovarian function and circulating amino acids of beef cows: 2. Excessive supply in varying concentrations from corn gluten meal

“…However, the exact mechanism of how AFC is mediated is unknown. Cushman et al (2014) suggested that AFC may be predetermined before birth, and may also be influenced through developmental programming. Yet, to our knowledge this study and research by Gunn et al (2014b) are the first reports suggesting that postnatal diet may alter AFC.…”