Source: Ontario Ministry of Agriculture, Food and Rural Affairs
There has been an increase in corn production in North America in recent years, leading to the uptake of feeding corn byproducts such as corn stover to cows as a low-quality roughage source. With increased production of biofuels like ethanol, there are also many valuable byproducts that can be used as feedstuffs. Being that winter-feeding cattle is a very expensive part of a cow-calf operation, finding less expensive feed alternatives is important to an operation’s success. A study by Kennedy et al. (2016) explored the feeding strategy of supplementing corn dried distillers grains plus solubles (DDGS) to late gestation beef cows fed low quality forages. The primary goal of the study was to investigate the impact of supplementation on:
- eating behavior
- body condition
- reproduction
What They Did
The study utilized corn stover, corn silage and DDGS to feed to Angus or Angus X Simmental late gestation cows. Twenty-seven multiparous cows were divided into two groups: a Control group (CON) and a Supplemented (SUP) group. Both groups were fed a free-choice base diet of corn stover and corn silage for 10 weeks before calving. The base diet was marginally deficient in net energy and deficient in rumen degradable protein according to the NRC 1996 model. The SUP group was fed DDGS twice daily at a rate of 0.3% of body weight (DM basis). After calving, all cows were put on a ration comprised of corn stover, corn silage and DDGS for the first part of their lactation.
Results
From this study, we learned that late gestation cows fed a low-quality forage with DDGS experienced the following:
Eating Behaviour: During late gestation, Supplemented cows consumed more feed per day and spent more time eating versus the Control cows. Supplemented cows ate forage at a faster rate and consumed forage in larger meals over the Control cows in the study. Control cows ate more forage meals overall. Into early lactation, Supplemented cows continued to spend more time eating, and consumed more per minute over the Control cows. Control cows continued to average more meals per day than Supplemented cows in early lactation.
Body Condition: As seen in the graphs below (Figure 1), during late gestation all cows started at a Body Condition Score (BCS) of approximately 3.5 (Canadian BCS system). The Supplemented group did not change significantly over the course of gestation. The Control group, however, dropped to a BCS of approximately 3 at calving, losing an average of 0.5 BCS through gestation. Supplemented cows gained body weight at a rate of 1.27 kg/day, whereas Control cows lost body weight at a rate of 0.23 kg/day over the gestation period. In early lactation, both the Control and Supplemented cows lost body condition initially.
Reproduction: Supplemented cows had heavier calves than the Control Cows. Control and Supplemented cows both had similar pregnancy rates at rebreeding.
Figure 1. Body Condition Score during late gestation
Impact on the Beef Industry
A possible explanation for the benefits seen in the current study is that in the Control diet, there is a high amount of fibre that contributes to a gut fill effect, where cows are not eating enough to meet their net energy (NE) requirements. This leads to weight loss. In the Supplemented diet, there is a higher amount of rumen degradable intake protein that leads to increased microbial activity. This causes increased nutrient utilization, increased ruminal fermentation, increased overall digestion of feedstuffs and ultimately, better animal performance.
The findings of this study suggest that there are many opportunities to incorporate corn byproducts in late gestation cow diets. Using available corn byproducts as a winter feed provides options to reduce feed costs in cow-calf production. When effectively incorporated into rations, DDGS has proven to be beneficial in maintaining Body Condition Score and body weight in late gestation cows, leading to effective fetal programming and improved overall beef cow productivity and profitability.
References
Kennedy, V.C., Bauer, M.I., Swanson, K.C. and Vonnahme, K.A. 2016. Supplementation of Corn Dried Distillers Plus Solubles to Gestating Beef Cows fed Low-Quality Forage I: Altered Intake Behaviour, Body Condition and Reproduction. J.Anim. Sci., 94 (11): 4619-4628.
Author: Julie French, Livestock Assistant -Dairy, OMAFRA
