Whole wheat hay can support beef production and limit environmental footprint
An international team of researchers, based at the University of Saskatchewan in Canada and the State Key Laboratory of Animal Nutrition at the Agricultural University of China, examined the use of whole wheat hay (WCWH) as a replacement for wild rye Chinese or Leymus chinensis(LC) in dairy foods.
The team has published its work in the Journal of Dairy Science.
“One would assume that WCWH could replace LC in the feed of finishing dairy bulls without having a negative effect. “the researchers said. “The objectives of the trial were to investigate the effects of WCWH as a LC surrogate on blood parameters, rumen fatty acids and microbial flora in Holstein bulls. ”
The team found few production differences for cattle given either feed. “
The data, they said, showed that WCWH can replace LC in the diet of fattening Holstein bulls without negative effects on blood indicators, fatty acids and the microbiome, they added.
Why whole wheat hay?
Chinese wild rye or LC is a species cultivated mainly in the Eurasian steppe but often imported into northern and central China, the researchers said. Farms in these areas have to purchase LC and transport it long distances. Therefore. they are looking for other sources of roughage to avoid LC’s high line shipping costs.
There are large amounts of wheat straw in these areas, they said. Straw is often burned, wasting resources and generating air pollution, the researchers noted.
“The applications of agronomy and plant breeding methods for the production of whole wheat (WCW), along with its potentially lower cost of production, have resulted in increased use of this crop as feed for ruminants,” they said. “For ruminants, ingestion of WCW, which consists of wheat straw and wheat grain, has a higher nutrient content and higher feed efficiency than ingestion of wheat straw alone.”
Previous work looked at the use of fermented whole wheat on dry matter consumption and rumen fermentation for beef cattle, they said. It has also been noted that adding grain to ensiled straw and straw can reduce enteric methane emissions.
Using WCWH is expected to save energy and reduce pollution, the researchers said. However, different types of forage can influence rumen fermentation and rumen microbes.
There is little published information regarding the use of WCWH as a replacement for LC, they said. “We tested several blood parameters, the fatty acid composition of rumen fluid and serum, and the microbiomes of Holstein bulls that were exposed to a modified diet.”they added.
In the feeding trial, 12 bulls were given one of four diets in a Latin 4×4 square format, the researchers said. Animals received each diet for a period of 22 days before switching to a new diet – 17 days for acclimatization and 5 days for sample collection.
The diets used included 45% roughage and 55% concentrate with four different levels of WCWH inclusion, they said. The inclusion rates were 0, 33, 67 and 100% in substitution for the LC.
Forages and residues were collected for analysis from day 18 to day 22, they said. Blood samples were taken for evaluation on day 18, and rumen samples were taken on day 22 of each feeding period.
For several of the areas examined, no differences were found for the bulls regardless of their diet, the researchers said.
“The results of this study indicate that the use of WCWH as a substitute for LC did not have a negative impact on blood parameters, rumen fatty acid levels and the composition of the microbial flora of the bulls. Holstein ‘they said. “These results provided further confirmation and explanation of the feasibility of using WCWH as fodder for ruminants in the agricultural industry.”
Rumen microbial flora was similar for bulls on all diets, and no changes were noted in the proportion of rumen protozoa and methanogens, they said. Ruminal amounts of bacteria Ruminococcus flavefaciensand Fibrobacter succinogeneswere also similar across plans.
“We conclude that switching the bull diet from LC to WCWH did not significantly affect rumen microbial flora in the present study.”
Likewise, few differences were found in the proportions of saturated and unsaturated fatty acids seen in rumen fluid or in monounsaturated or polyunsaturated fatty acids, the researchers said. The amounts of linoleic acid were similar among the diets, but tended to be higher for cattle fed the 100% WCWH diet.
The blood serum collected also showed similar results for the proportions of saturated, monounsaturated and polyunsaturated LCFAs, they said.
Cattle given the 100% WCWH diet had a higher concentration of urea nitrogen than those given the other diets, they said. However, there were no differences for “Serum glucose, triglycerides, cholesterol, total protein, albumin, HDL-C [high-density lipoprotein cholesterol], LDL-C [low-density lipoprotein cholesterol], and BHBA [beta-hydroxybutyrate] concentration.
Source: Journal of Dairy Science
Title: Effects of replacing Leymus chinensis with whole wheat hay on blood parameters, fatty acid composition and microbiomes of Holstein bulls
DOI: doi.org/10.3168 / jds.2017-13267
Authors: W. Niu, Y. He, H. Wang, C. Xia, H. Shi, B. Cao, H Su