Sunflower Screenings, Barley Malt or Wheat Midds in Lactating Beef Cow Diets

Vern Anderson

Carrington Research Extension Center

North Dakota State University

Abstract

Sunflower screenings fed at 37 percent of the diet dry matter were compared with barley malt and wheat midds in lactating cow diets that contained equal amounts of other co-product feeds (straw and potato waste) and alfalfa.  Mature and first-calf heifer pairs (n=122) were allotted after spring calving to the three dietary treatments and fed until the end of the 45-day breeding season. Observations of weight loss (-26 lb vs. +25 and +28) and condition score loss (-.12 vs. +.46 + .15) for sunflower screenings, barley malt and wheat midds diets, respectively, strongly indicate that the initial nutrient profile of sunflower screenings used to formulate the ration was not consistent with the subsequent product used.  Calf weight gain was similar for all treatments.  Pregnancy rate was only 23 percent in mature cows fed sunflower screenings, but satisfactory in other pens.  This observation may have been confounded by only one natural service sire used per pen.  Weight and condition score changes strongly suggest that producers who calve early and continue to feed before turnout should include a margin of safety in diet formulation if they use sunflower screenings, or use other more consistent feeds during this critical time. 

ntroduction

Numerous co-product and conventional feeds are available in quantity to North Dakota livestock producers.  Price versus nutrient content is the bottom line in evaluating all feeds.  Sunflower acres may increase with government support programs.  Even now, sunflower screenings are available during much of the year at highly competitive prices.  This commodity has been widely used in wintering cow diets with little liability.  Drought and other conditions may dictate producers seek feeds from off farm/ranch sources to support gestating and lactating cows.  This paper reports cow performance data from the use of sunflower screenings in diets for lactating cows.

Sunflower screenings can vary widely in nutrient content based on several factors.  Producers purchasing this commodity for feed have little control over quality and must adapt diets to meet the needs of the animals.  Table 1 presents nutrient analysis of sunflower screenings from samples taken during the course of this trial.  Crude protein varied from 11.5 to 15.7 percent.  Acid detergent fiber varied from 24.2 to 42.4 percent with neutral detergent fiber ranging from 37.1 to 53.1 percent.  Fat content is a function of seeds remaining in the screenings and varied from 12.9 to 21.1 percent. 

Table 1.  Variation in analysis of sunflower screenings

From a purely analytical perspective, sunflower screenings are very cost competitive for both energy and protein.  Fat is the major energy source and recent data on adding fat from oilseeds to gestating and lactating cow diets resulted in increased conception.  Further research is being conducted on type and amount of oil or oilseeds required and identifying the metabolic effects of supplemental fat.  Fat from sunflower seeds is a high- energy ingredient but the variation is high among screenings samples.  Further, in high fiberous feeds such as sunflower screenings, some of the crude protein (nitrogen) may not be digestible as it is tied up in the indigestible matrix of structural plant components (lignan and cellulose). 

Materials and Methods

Mature cross bred beef cows and first-calf heifers (n=111 pairs) and their calves were allotted to three treatments at the conclusion of spring calving in early May.  Lactating diets were formulated with primarily co-products including wheat straw, potato waste, and either sunflower screenings, barley malt, or wheat midds.  Diets were formulated to meet nutrient requirements for average milking beef cows at 12 percent crude protein and 66 percent TDN based on a preliminary nutrient analysis of respective ingredients.  Sunflower screenings were obtained from Dahlgren Inc., Grace City, ND.  Pelleted barley malt was procured from the Ladish Malt Plant at Spiritwood, ND, and consisted of the spent malt sprouts mixed with thin barley kernels and screenings.  Wheat midds were obtained from Dakota Growers Pasta Company, Carrington, ND.  Diet dry matter and as fed amounts are presented in Table 2.

Table 2.  Diets for lactating beef cows fed sunflower screenings, barley malt, or wheat midds.

The three treatments were evaluated with two replicates per treatment consisting of one pen of mature cows and their calves (n=26) and one pen of first-calf heifers and their calves (n=11) per treatment.  A 45-day natural service breeding season was used with cows randomly allotted by calving date to respective treatments.  Totally mixed rations were fed in limited amounts in fenceline bunks once daily.  Cow and calf weights and cow condition scores were recorded at the start of the trial in early May and at the end of the trial at the termination of the breeding season in late July. 

Results

Average cow weight changes (Table 3) were considered typical for the barley malt (+25 lbs.) and wheat midds treatments (+28 lbs.) but were less than predicted for the sunflower screenings treatment (-26 lbs.).  The pattern is consistent for both mature cows and first calf heifers.  The diet formulation based on a sample of sunflower screenings did not contain nutrients to support positive weight change although calf gains appear to be similar (Table 4).  Condition score changes (Table 5) are consistent with weight changes of cows and also suggest deficient nutrients in the sunflower screenings diet.  Pregnancy rate reveals a potentially serious problem if producers use co-products without constant vigilance of nutritional profile of specific ingredients.  While the rebreeding rate is satisfactory for the barley malt and wheat midds trial, and for the first-calf heifers in the sunflower screenings; weight and condition score losses may have been reduced cyclisity to minimal levels.  There is a potentially confounding effect of sire as only one natural service sire was used in each pen.  However, the mature bull used was a proven sire and had been tested satisfactory prior to the start of the breeding season.  None-the-less, indicators in this study suggest sunflower screenings should be carefully monitored for nutrient profile and given some margin of error in formulating diets for beef cows during breeding season.

Table 3.  Effect of co-product feeds on weight change of lactating cows

Table 4.  Effect of co-product feeds in lactating cow diets on calf gain

Table 5.  Effect of co-product feeds on condition score change of lactating cows

 Table 6.  Effect of co-product feeds in lactating cow diets on pregnancy rate.

Discussion

The variability in nutrients in sunflower screenings was not compensated for indietary changes during the trial, nor was an allowance for the indigestibility of this feed made in formulating the ration.  The lesson is to use lower levels of sunflower screenings in lactating cow diets, or compensate with a safety margin of other ingredients to insure enough nutrients for the cows’ requirements are provided.  Sunflower screenings may be used at higher levels in diets that are not as critical, such as post breeding season during fall or winter for gestating cows; but cow condition and some margin of safety should be observed in these diets as well.  Because sunflower screenings are so cost competitive, they are widely sought and used in forage-limited areas.  Their light weight and variability make them a difficult product to justify logistically and nutritionally at high levels in lactating beef cow diets.  Producers who calve early and continue to feed before turnout need to be particularly aware of the potential nutritional problems documented in this study.