Objectives were to investigate the effects of supplementation with corn dried distiller’s grains plus solubles (DDGS) to late gestating beef cows on arterial blood flow to the mammary glands during late gestation and early lactation; colostrum and milk production; dystocia and immunity; and calf BW. Cows were fed a control (CON; n = 15; 5.1% CP; 36.2% ADF) diet consisting of 90% corn stover and 10% corn silage on a dry basis offered ad libitum or CON diet with supplementation of DDGS (0.30% of BW; SUP n = 12). Mammary gland blood flow was assessed on day 245 of gestation. At parturition, maternal and calving parameters were assessed; colostrum and jugular blood was sampled; and dams were weighed. Mammary gland blood flow and milk production was measured on day 44 of lactation. Calves were weighed fortnightly for 8 wk and at weaning. Colostrum production tended to be greater in SUP dams than in CON dams (837 vs. 614 ± 95 g, P = 0.10). Calves of SUP dams were heavier at birth and 24 h (0 h, 43.2 vs. 39.8 ± 1.0 kg, P = 0.02; 24 h, 44.0 vs. 40.4 ± 1.1 kg, P = 0.02). At birth and 24 h, blood pCO2 was greater in calves born to SUP dams (6.82 vs. 6.00 ± 0.41 kPa, P = 0.04). Serum IgG did not differ (P = 0.21) at 24 h. Ipsilateral mammary gland blood flow of SUP cows was greater than CON cows (2.76 vs. 1.76 ± 0.30 L/min; P = 0.03); however, when summed with contralateral, total blood flow was similar (P = 0.33). Hemodynamic measures on day 44 of lactation were similar (P ≥ 0.32). Milk production tended to be increased (13.5 vs. 10.2 ± 1.2 kg/d, P = 0.07) in SUP vs. CON cows. Despite similar BW through 56 d, calves from SUP cows were heavier (P = 0.04) at weaning (309.7 vs. 292.0 ± 6.0 kg). In conclusion, we accept our hypothesis that DDGS supplementation during gestation influenced mammary blood flow, milk production and calf weights. These findings implicate maternal nutrition’s leverage on both nutrient and passive immunity delivery to the calf early in life as well as potential advantages on long-term performance.

The objective of this study was to investigate the effects of supplementing dried distillers' grains plus solubles (DDGS) during late gestation on uterine blood flow (BF), circulating steroid hormones and hepatic steroid metabolizing enzymes, and calf and placental weights. Multiparous beef cows were randomly divided into a control group (CON; = 15) consuming a diet containing 90% corn stover and 10% corn silage (DM basis) for ad libitum intake and a treatment group (SUP; = 12) consuming the same diet and DDGS (0.3% of BW). Corn silage inclusion was increased to 30% as gestation progressed to meet increasing caloric requirements. Ipsilateral and contralateral uterine BF and cross-sectional area (CSA) of each uterine artery were measured by Doppler ultrasonography on d 180, 216, and 246 of pregnancy. Contralateral BF and CSA increased ( < 0.01) as gestation advanced. Ipsilateral BF and CSA was affected by a treatment × day of gestation interaction ( < 0.05). A main effect of treatment ( = 0.02) and day ( < 0.01) was observed for total BF; BF increased over time and SUP cows had greater BF than CON cows. Circulating concentrations of both progesterone (P4) and estradiol-17β (E2) were affected by an interaction of treatment and day ( < 0.01). Concentrations of circulating E2 steadily increased throughout the study and were greater in CON cows than in SUP cows by d 242. Concentrations of P4 also increased over time; P4 of CON cows was greater than that of SUP cows by d 242. Uridine 5'-diphospho-glucuronosyltransferase (UGT) and cytochrome P450 1A (CYP1A) activity increased with advancing gestation ( < 0.01). There was greater UGT activity ( < 0.05) and a trend for greater CYP1A activity ( = 0.06) in SUP cows than in CON cows. Activity of cytochrome P450 3A was greater ( < 0.01) in SUP cows and decreased ( < 0.05) with advancing gestation. Supplementing DDGS to cows fed low-quality forage during late gestation increased uterine BF but decreased circulating E2 and P4 concentrations and altered hepatic steroid metabolizing enzyme activity. It was anticipated that enzyme activity would reflect circulating hormone levels; however, our data suggests the observed increases in BF are not driven by alterations in hormone concentration. Therefore, further research is warranted to elucidate the underlying mechanisms.

Eighty-one steers [428 ± 3.5 kg of body weight (BW)] were used to determine the effect of grain type (corn vs. barley) and oil concentration of dried corn distillers grains plus solubles (DDGS; moderate = 7.9% vs. low = 4.5% ether extract) on growth performance, feeding behavior, and carcass characteristics. Intake and feeding behavior traits were calculated from data generated via the Insentec feeding system. Steers were slaughtered with an average BW of 668 ± 4.4 kg. Final BW and average daily gain (ADG) were not affected by grain type or DDGS oil concentration. Dry matter intake (DMI) decreased (P = 0.002) and gain:feed ratio (G:F) increased (P = 0.01) in steers fed diets containing barley. Daily visits to the feeder decreased (P = 0.05), but time eating per visit increased (P = 0.03) in steers fed diets containing barley than corn. Plasma urea-N concentration was greater (P ≤ 0.05) in steers fed diets containing barley than corn and in steers fed diets containing low-oil DDGS than moderate-oil DDGS diets. There was no effect of treatment on carcass characteristics. These data indicate that steers fed diets containing barley had improved G:F and that including low-oil vs. moderate-oil DDGS in a finishing diet does not influence growth performance, feeding behavior, or carcass measurements.

To determine the effects of finishing system (conventional vs. natural), dietary adaptation length (14 vs. 28 d), and direct-fed microbial (DFM) supplementation (no DFM vs. DFM) on growth performance and feeding behavior, 120 yearling steers (390 ± 2.8 kg) were used in a completely randomized design with a 2 × 2 × 2 factorial arrangement of treatments. Feed intake was monitored using the Insentec feeding system. Blood samples were collected every 28 d. After 140 d on feed, steers were slaughtered and carcass characteristics collected. Conventionally fed steers had greater (P ≤ 0.001) final BW, carcass weight, and dressing %. Dry matter intake was not influenced (P ≥ 0.31) by treatment. Length of dietary adaptation period did not influence (P ≥ 016) final BW, ADG, and G:F. There was a feeding system × DFM interaction (P ≤ 0.02) for ADG and G:F with conventionally fed steers fed DFM having the greatest (P ≤ 0.05) and naturally fed steers supplemented with DFM having the least (P ≤ 0.05) ADG and G:F. Number of visits to the feed bunk and number of meals per day did not differ (P > 0.05) among treatments. Time eating per visit and per meal was greater (P = 0.05) in steers supplemented with DFM than in steers not supplemented with DFM. On day 56 and 140, plasma glucose concentration was greater (P ≤ 0.03) in steers adapted in 14 d than in steers adapted in 28 d. On day 84, plasma glucose concentration was greater (P = 0.02) in naturally fed compared to conventionally fed steers. On day 112, there was a dietary adaptation period × DFM interaction (P = 0.004) for plasma glucose concentration with glucose concentration greatest (P ≤ 0.05) in steers adapted in 14 d supplemented with DFM and in steers adapted in 28 d not supplemented with DFM, least for steers adapted in 28 d supplemented with DFM, with steers adapted in 14 d not supplemented with DFM intermediate (P ≤ 0.05). On day 112 and 140, plasma urea N concentration was greater (P ≤ 0.05) in steers adapted in 28 d than in steers adapted in 14 d. These data indicate that conventionally fed steers generally had improved growth performance compared to naturally fed steers. Length of dietary adaptation and DFM supplementation had minimal effects on growth performance but did interact with feeding system to influence feeding behavior and blood metabolite concentrations.

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