Does health start in the womb? Impact of maternal undernutrition during gestation on the reproductive and cardiovascular system of female offspring in dairy cattle

Female beef calves born to mothers exposed to a nutritionally restricted diet in early gestation had a reduced total number of ovarian follicles (ovarian reserve; Mossa et al., 2013). The aim of this work was to investigate the impact of maternal nutrient restriction from shortly before conception to early gestation on the development of the reproductive tract in female progeny in dairy cattle. Methods Holstein-Friesian heifers (n=42) homogenous for age (14-17 mo.) and weight (366.241.1 kg) were randomly assigned to three experimental groups and, starting 10 d (days) before artificial insemination (AI), were individually fed at: (i) 0.6 of their maintenance energy requirements (M) up to day 80 (Nutrient Restricted,NR80;n=16) or (ii) 120 DG (Days of gestation;NR120,n=16), and (iii) 1.8M until 120 DG (Control,C; n=10). Estrus cycles were synchronized, and heifers were inseminated with sex-sorted semen from a single sire. Pregnancy was diagnosed and confirmed via ultrasound (MyLab Omega, Esaote, with 4-10MHz sectorial probe) 28 and 55 days after AI, respectively. After the end of the differential diet, all heifers were group fed ad libitum until calving. Twenty-two single female calves were born (NR80=8;NR120=9;C=5); body weight (BW) and height at withers (H) were measured regularly until slaughter at 4.5 mo. of age. Ovaries were measured, weighed, all visible antral follicles were counted and cumulus oocytes complexes (COCs) were collected. Data were analyzed with R software with One-way ANOVA and mean contrast separated with Tukey post-hoc test. Results are expressed as mean±SEM. BW at birth was lower in NR80 than C calves (p<0.05) and similar between NR120 and NR80 (C=41.4±1.1;NR80=36.7±0.6;NR120=38.3±1.2 kg), while BW at slaughter and H were similar among groups. Ovarian volume was similar among groups. Ovarian weight was lower (p<0.05) in NR120 compared to C and similar between NR120 and NR80 (C=10.41.3;NR80=7.4±0.9;NR120=6.70.5 g). NR120 heifers had less (p<0.05) visible antral follicles than C whereas no difference was detected between NR80 and C (C=197.236.5;NR80=150.1±20.9;NR120=104.210.7). Fewer COCs were retrieved (p<0.05) from NR120 and NR80 compared to C ovaries (C=75.8±12.57;NR80=48±3.5;NR120=48.2±6.68). Conclusion Maternal exposure to undernutrition from preconception to day 120 of gestation resulted in a reduction of ovarian weight, visible antral follicles and retrieved COCs in their female offspring indicating a potential impairment of the size of the ovarian reserve.

Introduction Female beef calves born to mothers exposed to a nutritionally restricted diet in early gestation had a reduced total number of ovarian follicles (ovarian reserve; Mossa et al., 2013). The aim of this work was to investigate the impact of maternal nutrient restriction from shortly before conception to early gestation on the development of the reproductive tract in female progeny in dairy cattle. Material and Methods Holstein-Friesian heifers (n=42) homogenous for age (14-17 mo.) and weight (366.241.1 kg) were randomly assigned to three experimental groups and, starting 10 d (days) before artificial insemination (AI), were individually fed at: (i) 0.6 of their maintenance energy requirements (M) up to day 80 (Nutrient Restricted,NR80;n=16) or (ii) 120 DG (Days of gestation;NR120,n=16), and (iii) 1.8M until 120 DG (Control,C; n=10). Estrus cycles were synchronized, and heifers were inseminated with sex-sorted semen from a single sire. Pregnancy was diagnosed and confirmed via ultrasound (MyLab Omega, Esaote, with 4-10MHz sectorial probe) 28 and 55 days after AI, respectively. After the end of the differential diet, all heifers were group fed ad libitum until calving. Twenty-two single female calves were born (NR80=8;NR120=9;C=5); body weight (BW) and height at withers (H) were measured regularly until slaughter at 4.5 mo. of age. Ovaries were measured, weighed, all visible antral follicles were counted and cumulus oocytes complexes (COCs) were collected. Data were analyzed with R software with One-way ANOVA and mean contrast separated with Tukey post-hoc test. Results are expressed as mean±SEM. Results BW at birth was lower in NR80 than C calves (p<0.05) and similar between NR120 and NR80 (C=41.4±1.1;NR80=36.7±0.6;NR120=38.3±1.2 kg), while BW at slaughter and H were similar among groups. Ovarian volume was similar among groups. Ovarian weight was lower (p<0.05) in NR120 compared to C and similar between NR120 and NR80 (C=10.41.3;NR80=7.4±0.9;NR120=6.70.5 g). NR120 heifers had less (p<0.05) visible antral follicles than C whereas no difference was detected between NR80 and C (C=197.236.5;NR80=150.1±20.9;NR120=104.210.7). Fewer COCs were retrieved (p<0.05) from NR120 and NR80 compared to C ovaries (C=75.8±12.57;NR80=48±3.5;NR120=48.2±6.68). Conclusion A potential impairment of the ovarian reserve can be determined independently from the duration of maternal undernutrition, shortly from preconception to 80 or 120 days of gestation.