The cost for wintering cows fed hay and protein supplement for 4-5-months is expensive and amounts to the largest expense for producing calves in the cow-calf business.

Cow wintering research was designed to evaluate gestating cow winter feeding methods and associated cost. One hundred forty-four, 3-10-year-old, May-June calving crossbred cows were used in the 134-day (4.39 months) study that compared three annual forage residues for winter grazing. A drylot control (C) group of cows were fed hay and protein supplement. Compared to the control group of cows, one group of cows grazed a 7- specie cover crop followed by corn and sunflower residues (CC-RES) and a second group of cows grazed stockpiled mixed bromegrass and crested wheatgrass pastures followed by corn stalk residue (GRAS-RES). Cows in all of the winter grazing treatments compared received 1.74 lb (DM) of a 32% CP supplement ($339.25/T). After grazing approximately 50 - 60% of the available low-quality residue or stockpiled grass, the cows received hay until the study ended in April. Overall, total gain during the 134-day wintering period for the C, CC-RES, and GRAS-RES treatments was 205, 146, and 112 lb., respectively. Body condition score for the C and CC-RES cows increased 0.79 and 0.71 of a condition score/cow; (P = 0.05), however the GRAS-RES group’s BCS did not change (5.4).

Reproductively, the following breeding season and subsequent calving percentage did not differ for the first (P = 0.12), second (P = 0.15), and third (P = 0.26) calving cycles, percent of non-pregnant cows (P = 0.47), and total percent calving (P = 0.46). Total percent of open cows and cows calving for the C, CC-RES, and GRAS-RES treatments was 10.7, 4.8, 10.4% opens and calving rate was 89.3, 95.2, 89.6%, respectively. Cows calving during the May-June timeframe calve on lush spring crested wheatgrass and native perennial pasture; which are supportive for successful rebreeding performance.

Overwintering cost for the three methods compared was markedly different. Using $80/T hay price, the hay cost/cow for the C, CC-RES, and GRAS-RES was $188.96, $72.96, and $35.64/cow, and the 32% CP supplement was $36.30/cow, respectively (P = 0.001). Cover crop expense/cow was $36.55. Combining the cost for the 32% CP supplement, annual forage farming costs, and property tax expenses, the total wintering cost for the C, CC-RES, and GRAS-RES was $225.26, $145.81, and $71.94/cow, respectively.

Considering these winter-feeding costs, feeding hay for the 4.39-month wintering period cost 3.13 times more than winter grazing set aside stockpiled improved forage and annual forage residue.

On a calendar year basis, C, CC-RES, and GRAS-RES cows grazed 7.6, 10.0, and 11.1 months of the year, respectively. Reserving improved grass pastures and annual forage corn, sunflower, and cover crop for winter grazing has huge potential for reducing winter feed cost. However, the protein content of mature forage and residues is low and supplemental protein is necessary. For a 1,400 lb. cow, providing crude protein at 9.5 to 10.5% of the diet dry matter will be adequate. Due to a unique characteristic of ruminants in which ammonia is recycled through the saliva, protein supplement does not need to be delivered daily. For example, if feeding 1.5 lb./day, then deliver 4.5 lbs. every third day. Due to the higher amount delivered, supplement ingredients must not create a potential for bloat. Distillers dried grains with solubles is an excellent ingredient that does not cause bloat.

Caution. North Dakota winters are unpredictable and can be very harsh. The authors suggest cattle producers that are winter grazing stockpiled forages and residues or are considering winter grazing have one and, preferably, two years hay supply on hand as a precaution for weather conditions that preempt winter grazing.

Songül Şentürklü, Visiting Scholar, Department of Animal Science, Çanakkale Onsekiz Mart University, BMYO, Çanakkale, Turkey, contributed to this update.