1. Effect of Chitosan Inclusion and Dietary Crude Protein Level on Nutrient Intake and Digestibility, Ruminal Fermentation, and N Excretion in Beef Heifers Offered a Grass Silage Based Diet
- Author
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Tommy M. Boland, Michael McDonald, Eleonora Serra, Gaurav Rajauria, Stuart F. Kirwan, and K.M. Pierce
- Subjects
Nitrogen balance ,010504 meteorology & atmospheric sciences ,Silage ,ruminal fermentation ,nitrogen excretion ,Beef cattle ,nitrogen balance ,01 natural sciences ,Article ,Excretion ,Rumen ,Animal science ,beef cattle ,Latin square ,crude protein ,lcsh:Zoology ,Dry matter ,lcsh:QL1-991 ,0105 earth and related environmental sciences ,lcsh:Veterinary medicine ,General Veterinary ,Chemistry ,0402 animal and dairy science ,food and beverages ,04 agricultural and veterinary sciences ,040201 dairy & animal science ,Belgian Blue ,lcsh:SF600-1100 ,Animal Science and Zoology ,chitosan - Abstract
Nitrogen (N) use efficiency in beef cattle is low (10–20%), resulting in large amounts of N excreted into the environment. The objective of this study was to evaluate the effects of chitosan inclusion and dietary crude protein (CP) level on nutrient intake and digestibility, ruminal fermentation, and N excretion in beef heifers. Eight Belgian Blue × Holstein Friesian cross beef heifers (752 ± 52 kg BW) were used in a 4 × 4 Latin square with a 2 × 2 factorial design. Factors were dietary CP concentration—high CP, 16% (HP) or low CP, 12% (LP)—and chitosan inclusion—0 or 10 g kg−1 dry matter (DM) offered at 50:50 forage concentrate ratio on a dry matter (DM) basis. Apparent total tract digestibility of DM, organic matter (OM), and CP were reduced (p <, 0.001) with chitosan inclusion, whereas offering the HP diets increased apparent total tract digestibility of CP (p <, 0.001). Offering the HP diets increased urinary N excretion (p <, 0.001), while chitosan inclusion increased N excretion in faeces (p <, 0.05). Ruminal pH was increased with chitosan inclusion (p <, 0.01). There was a CP × chitosan interaction for rumen ammonia (NH3) concentrations (p <, 0.05). Including chitosan in the HP diets increased ruminal NH3 concentration while having no effect on the LP diets. Urinary N excretion was increased with increased levels of CP, but chitosan inclusion increased the quantity of N excreted in the faeces.
- Published
- 2021