Date of Award


Degree Type


Degree Name

Master of Science (MS)


Animal Science

First Advisor

Jon P. Schoonmaker

Committee Chair

Jon P. Schoonmaker

Committee Member 1

Ronald P. Lemenager

Committee Member 2

Kolapo Ajuwon


The main goal for a cow-calf producer is profitability, which requires optimum reproductive performance, while keeping feed costs low and ensuring that nutritional needs are met. Cow herds are grazed on pasture or crop residues, but these may not always meet nutritional requirements. Ethanol co-products such as dried distiller's grains with solubles (DDGS) and condensed distiller's solubles (CDS) may be supplemented to increase the energy and protein concentration of the diet. Recently it has been discovered that maternal diet can have long lasting effects on progeny growth and development. Thus, the effects of feeding the ethanol co-products DDGS and CDS to gestating or lactating beef cow performance and calf growth was investigated in several experiments. The hypothesis for this thesis was that feeding ethanol co-products to cows during gestation and/or lactation would improve cow performance and reproductive efficiency while improving the pre- and post-weaning growth of their calves relative to control diets that did not contain ethanol co-products.

In the first experiment, cows with male progeny were fed isocaloric diets of DDGS or soybean meal (SBM) from calving until mid-lactation to determine the effect of DDGS on cow performance, milk composition and calf growth. Feeding DDGS increased conception (P < 0.02) but not pregnancy rates (P = 0.64), did not alter cow BW (P ≥ 0.43), BCS (P ≥ 0.13) or milk production (P ≥ 0.75) but altered milk composition compared to diets that did not contain DDGS. Distiller's grains with solubles had no effect on short chain fatty acids (FA) in milk (P ≥ 0.13), but did decrease medium chain FA (P < 0.01) and increase long chain FA (P < 0.01). Saturated FA content of milk was decreased (P < 0.01) in DDGS cows, subsequently increasing monounsaturated FA (P < 0.01) and polyunsaturated FA (P < 0.01), including conjugated linoleic acid (CLA; P < 0.01). Feeding DDGS to dams during lactation resulted in greater calf ADG (P < 0.01) and heavier weights by the end of the trial (P < 0.01). Post-trial ADG was similar (P = 0.90) and calves whose dams were fed DDGS remained heavier at weaning (P < 0.01).

In the second experiment, male calves from the first experiment were placed in a feedlot to examine the effect of maternal diet during lactation on long-term progeny growth. Maternal treatment during lactation had no effect on days on feed (P = 0.42), ADG (P = 0.80), DMI (P = 0.76) or feed efficiency (P = 0.90) during the finishing phase. Glucose (P ≥ 0.17) and insulin (P ≥ 0.16) clearance were not affected by maternal nutrition during lactation, nor was glucose area under the curve (P = 0.27), insulin area under the curve (P = 0.37) or the glucose to insulin ratio (P = 0.40). Hot carcass weight (P = 0.54), dressing percent (P = 0.50), fat thickness (P = 0.71), longissimus area (P = 0.17), percent kidney pelvic heart fat (P = 0.31) and yield grade (P = 0.19) were not impacted. Marbling, however, was decreased (P = 0.04) in progeny whose dams were fed DDGS compared to progeny whose dams were fed a control diet.

In the third experiment, two studies were conducted to determine the effects of CDS inclusion with corn stover during gestation or lactation on beef cow and calf performance. Increased levels of CDS improved feed intake, although intake was hindered by high levels of corn stover. Cows lost weight (P = 0.05) when fed CDS during gestation but not lactation (P > 0.22), which may have been due to the greater levels of corn stover in the gestation diet. While cows lost weight, pregnancy rates were not negatively affected (P = 1.00). Milk urea nitrogen (P = 0.08) tended to increase when CDS was fed during lactation, but no other changes in milk composition were apparent when CDS was fed during gestation or lactation (P ≥ 0.19). Feeding CDS during gestation had no effect on calf birth (P ≥ 0.29) or weaning weights (P ≥ 0.42), but calves whose dams were fed CDS during lactation grew more slowly (P = 0.05).

In conclusion, these experiments demonstrate that feeding DDGS during lactation can improve cow efficiency and reproductive performance and may be an effective method for improving pre-weaning calf growth, but has little effect on long-term feedlot performance of male progeny. If CDS is fed to gestating or lactating beef cows, it should be included at increased levels or with higher quality forages to prevent decreased in intake and performance.