Crop and Livestock Enterprise Integration: Effects of Annual Crops Used for Fall Forage Production On Livestock Productivity.

Diversification of farm enterprises is important to maintain sustainable production systems.  Systems that integrate crops and livestock may prove beneficial to each enterprise.  Our objectives were to determine the effects of annual crops grazed in the fall and early-winter period on cow and calf growth.  Starting in September of 2007, forty-two lactating Angus cows (avg. body weight = 595 ± 83 kg and body condition score = 5.1) and six ruminally-cannulated beef cows were randomly assigned to one of three treatments being either 1) continuous grazing of a 6 ha perennial grass pasture plus supplemental grass hay if needed (Control); 2) continuous grazing of a 5.3 ha Altai wildrye pasture (Altai); or 3) rotationally graze 5.45 ha field sub-divided into three 1.82 ha strips seeded to either oats underseeded with alfalfa, hairy vetch and red clover; brown-midrib sorghum ´ sudan underseeded with sweet clover and red clover; and corn stalks residue (Annuals).  Body weight and condition scores were measured when cattle reached the end of each annual crop, which was considered an experimental period.  Calves remained with cows for the first experimental period and were weaned when cows were rotated to the corn residue.  Weather varied from year to year causing a treatment × experimental period × year interaction for cow average daily gain and body condition score change.  All treatments lost weight while calves were nursing.  However, once calves were weaned, Controls continued to lose body weight and condition score in two of four years, whereas cows grazing Annuals and Altai gained weight in two of four years, with Annuals gaining more weight than Altai during experimental period 2 and 3.  Calf average daily gain was 1.17, 1.05, 0.99 kg/ day for Annuals, Altai, and Control, respectively. Overall, the harsh winters experienced over the course of this experiment caused all cattle to lose weight.  Nevertheless, body weight loss was only -0.06 kg/day for cows grazing annual crops compared to -0.29 and -0.15 kg/day for Control and Altai, respectively.  Therefore, using annual crops and crop residue for fall and early winter feed may be a viable option for feeding beef cows if economic evaluation is positive for the integrated approach.