Effects of planting date on fiber digestibility of whole-crop barley and productivity of lactating dairy cows.
Objectives of the study were to evaluate the effect of planting date on in vitro neutral detergent fiber digestibility (IVFD) of whole-crop barley (Hordeum vulgare) and its effects on productivity of lactating dairy cows. Two cultivars of barley were planted on May 5 (BM) and June 7 (BJ), 2005 at the Edmonton Research Station, University of Alberta. They were harvested at late-dough stage on July 26 and August 25, respectively, for BM and BJ and ensiled. The BJ had greater 30-h IVFD (61.2 vs. 51.9%) and crude protein concentration (12.4 vs. 8.7%) at harvest compared with BM. Thirty lactating cows, including 6 ruminally cannulated cows, in mid to late lactation (183 +/- 71.7 d in milk; mean +/- standard deviation) were fed diets containing BM or BJ at 58.5% of dietary DM in a crossover design with 19-d periods. The dietary neutral detergent fiber concentration was 30.6 and 28.8% for BM and BJ diets, respectively. Dry matter intake and milk yield were not affected by treatment and averaged 20.2 and 27.2 kg/ d, respectively. The lack of responses could have been attributed to the low-energy demands for cows used in this experiment; ruminal physical fill might not have limited dry matter intake. However, cows fed BJ had greater total tract dry matter digestibility (68.9 vs. 66.1%) and tended to increase body weight gain (864 vs. 504 g/d) compared with those fed BM. Delaying the planting date of barley altered its growing environment and affected nutrient composition and IVFD of whole-crop barley and energy availability to animals. Further research is needed to confirm if the planting date consistently affects nutrient composition and IVFD of barley at harvest.
Chow
L O
LO
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada.
Baron
V S
VS
Corbett
R
R
Oba
M
M
D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D001824:Body Constitution / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D002404:Catheterization / Q000662:veterinary; D002417:Cattle / Q000378:metabolism*; D018592:Cross-Over Studies; D003612:Dairying / Q000379:methods; D004043:Dietary Fiber / Q000032:analysis / Q000378:metabolism*; D004063:Digestion; D005227:Fatty Acids / Q000032:analysis; D005260:Female; D001467:Hordeum / Q000378:metabolism*; D007774:Lactation / Q000502:physiology*; D008892:Milk / Q000737:chemistry; D011891:Rain; D012417:Rumen / Q000378:metabolism; D013696:Temperature; D013997:Time Factors
D004043:Dietary Fiber; D005227:Fatty Acids