Chadron State College
The prevalence of late spring/early summer calving (May-June) and the use of early weaning with environmentally adapted cows is not a new concept, however it is not a common occurrence in Northwest Nebraska nor the Northern Great Plains. Over time smaller framed cows with less milk production have been systematically replaced by higher milk producing and larger framed ones. In areas such as Northwest Nebraska (semi-arid) this has led to less efficient use of rangelands mainly due to increased supplemental feeding in order to maintain the larger and more nutritionally demanding animals. With costs of production rising and profit margins shrinking, many producers are re-thinking their production systems. Grain prices and fuel prices currently continue to set record highs. Many ranchers have large framed mother cows weighing well over 1250 lbs, and most also calve in late winter/early spring in cold temperatures with risks of calf mortality and poor forage conditions. This creates a demand on feedstuffs that must be purchased and brought to the ranch or produced on site with more intensive labor and machinery. Studies such as Reisenauer et al., (2007) have been done comparing calving seasons and found that the traditional early spring calving (without added mortality from adverse climate) produced the highest gross margin in the Northern Great Plains. This approach was based on the supplementation of “normal” (large, high producing) cows to maintain them in a good body condition throughout the year. Genetic makeup or individual animal selectivity in the efficiency of the cows was not factored. It has been shown that ranchers can select for (over time) animals in their herd to maximize efficiency with little or no supplementation (Pharo, 2008), such as selecting for smaller framed cow with less milk production that has a calf every year. It should also be noted that in Reisenauer et al., (2007) prices such as for fuel and feedstuffs were calculated at historical levels, not reflecting today’s prices. Other studies such as Younglove (1998) suggest that native shortgrass range appears more suited to later calving (May-June) cow herds and can result in lowering input costs. It has also been proven in studies such as Adams et al., (2001), that changing the calving season from late winter/ early spring to late spring/ early summer and weaning earlier can result in less harvested feed used and lower labor requirements. The higher forage quality during late summer-early fall compared to late fall-winter provides an opportunity to either maintain or increase the body condition score (BCS) of cows by simply weaning the calf (Ciminski, 2002). Thus we can assume a combination of matching calving season and weaning dates to existing forage resources and selecting efficient animals to fit our environment that ranchers can become more efficient and profitable.
Concepts of matching the forage quality to the nutritional requirements of the cow are key, however selection of an efficient cow to not only survive but to produce a calf every year is paramount. Many studies have been conducted in strategically feeding cows to maintain body condition at specific times of the year, and at specific stages of gestation, lactation, and growth. However, selection of proper sire genetics and cow selectivity/culling procedures are seldom mentioned. Selection of sires who are proven to be efficient converters of grass to beef and cows that can thrive and reproduce on local ranch forage resources are of equal importance to overall ranch productivity and profitability.
Efficiency of livestock production might improve if nutrient demand associated with animal physiological state...