A study was conducted on an annual cropped field near Lanigan, Saskatchewan over two years (2005-2006, 2006-2007) to evaluate the effects of three extensive winter feeding systems (bale grazing (BG), swath grazing (SG) and straw-chaff grazing (ST-CH)) and one intensive winter feeding system (drylot (DL)) on cow performance, soil nutrients, crop yield and system cost of production.<p> Differences in BW (P<0.05) were observed during the 2005-2006 study period with the greatest difference occurring with cows in the SG feeding system. Cows grazing swaths (SG) had a BW loss of 8.0 kg over the 78 d trial period, however these cows consumed 15% less DM and 13% less TDN than cows bale grazing, grazing crop residue or fed in drylot pens. Differences in BW change (P<0.05) were also observed during Yr 2 between the cows fed drylot and cows grazing barley straw-chaff, 32.9 and 6.5 kg, respectively. This difference in body weight change (BW∆) and lower TDN consumption may be attributed to inaccessibility of the straw-chaff feed in the field, due to inclement weather and would suggest a lengthy acclimation period for extensive field grazing systems.<p> The effects of extensive winter feeding system on soil nutrients and soil structure were determined the following spring after winter grazing. NO3-N levels at the low slope position in the 0-15 cm depth were 53% higher on the BG sites than the ST-CH sites. This may be attributed to the larger concentration of feed, thus feed nutrients, in the BG feeding system. Phosphorus levels on the BG wintering sites were 34% higher than levels in the SG or ST-CH sites. Crop biomass measured on the BG sites was consistent with soil nutrients captured, resulting in a 15% increase in biomass compared to ST-CH and SG sites. Soil nutrient and crop biomass distribution was consistent among winter grazing sites with the ST-CH sites having the most uniform distribution of nutrients and crop biomass, and the BG sites having the least.

A study was conducted on an annual cropped field near Lanigan, Saskatchewan over two years (2005-2006, 2006-2007) to evaluate the effects of three extensive winter feeding systems (bale grazing (BG), swath grazing (SG) and straw-chaff grazing (ST-CH)) and one intensive winter feeding system (drylot (DL)) on cow performance, soil nutrients, crop yield and system cost of production.<p> Differences in BW (P<0.05) were observed during the 2005-2006 study period with the greatest difference occurring with cows in the SG feeding system. Cows grazing swaths (SG) had a BW loss of 8.0 kg over the 78 d trial period, however these cows consumed 15% less DM and 13% less TDN than cows bale grazing, grazing crop residue or fed in drylot pens. Differences in BW change (P<0.05) were also observed during Yr 2 between the cows fed drylot and cows grazing barley straw-chaff, 32.9 and 6.5 kg, respectively. This difference in body weight change (BW∆) and lower TDN consumption may be attributed to inaccessibility of the straw-chaff feed in the field, due to inclement weather and would suggest a lengthy acclimation period for extensive field grazing systems.<p> The effects of extensive winter feeding system on soil nutrients and soil structure were determined the following spring after winter grazing. NO3-N levels at the low slope position in the 0-15 cm depth were 53% higher on the BG sites than the ST-CH sites. This may be attributed to the larger concentration of feed, thus feed nutrients, in the BG feeding system. Phosphorus levels on the BG wintering sites were 34% higher than levels in the SG or ST-CH sites. Crop biomass measured on the BG sites was consistent with soil nutrients captured, resulting in a 15% increase in biomass compared to ST-CH and SG sites. Soil nutrient and crop biomass distribution was consistent among winter grazing sites with the ST-CH sites having the most uniform distribution of nutrients and crop biomass, and the BG sites having the least.

The objective of this research was to determine the effect of stage of maturity at the time of harvest for barley and oat whole-crop forage on feed intake, ruminal fermentation and digestibility, and the impact forage allocation has on intake and ruminal fermentation. In the first 2 studies, whole-crop barley (Study 1; c.v. CDC Cowboy) and oat (Study 2; c.v. CDC Weaver) forage were harvested at the late milk (LM), hard dough (HD) and ripe (RP) stages and offered ad libitum to ruminally cannulated heifers. Diets were supplemented in an attempt to balance crude protein (CP) among treatments. Heifer performance, dry matter intake (DMI), ruminal fermentation parameters, ruminal digestibility, and total tract digestibility were evaluated. In Study 3, whole-crop oat (c.v. CDC Weaver) forage harvested at HD and RP was offered ad libitum to ruminally cannulated heifers in either daily (1-D) or 3 d (3-D) allocations. Dry matter intake and ruminal fermentation parameters were measured. In Study 1, harvest maturity of barley did not affect DMI (P = 0.70; average 5.4 kg/d) or average daily gain (ADG; P = 0.64). Total tract digestibility was decreased for barley harvested at HD (P = 0.003), but harvest maturity did not affect daily digestible energy (DE) intake (P = 0.52). Minimum ruminal pH for heifers fed the barley forage was lowest for LM (6.09), intermediate for RP (6.13), and greatest for HD (6.25; P = 0.016). Total short chain fatty acid (SCFA) concentrations were not affected by harvest maturity (P = 0.36). In Study 2, harvest maturity of whole-crop oat did not affect DMI (P = 0.26; average 8.1 kg/d) or ADG (P = 0.52). There were no effects of harvest maturity of oat forage on total tract digestibility (P = 0.78) or daily DE intake (P = 0.68). The minimum ruminal pH from heifers fed oat forage was lowest for HD (5.84; P = 0.012), intermediate for RP (5.94) and greatest for LM (5.99). There was no effect of harvest maturity of oat forage on total SCFA concentrations (P = 0.21). The quantity of forage allocation (Study 3) had no effect on total or forage DMI over a 3-d duration (P ≥ 0.47). Throughout the 3-d feeding period, 3-D allocated heifers had a reduction in the area pH was under 5.8 (214.4, 79.5 and 10.9 pH × min/d, for d 1, 2 and 3, respectively; P = 0.003). Total SCFA concentrations were not affected by forage allocation or harvest maturity (P ≥ 0.14), however there was an interaction of forage allocation and day in the feeding cycle (P = 0.046). Heifers allocated 1-D had no change iii in total SCFA concentration over the 3-d feeding period (averaged 122 mM), but 3-D allocation had elevated concentrations on d 1 (138 mM) intermediate on d 2 (135 mM) and decreased on d 3 (117 mM). These data suggest that harvesting barley and oat at the HD stage improves DM yield without negatively affecting cattle DMI and ADG. These data also suggest that providing 3-d allocations of forage does not affect DMI, but can increase daily fluctuations of ruminal pH and ruminal SCFA concentrations.