title: Effect of limit feeding high- and low-concentrate diets with Saccharomyces cerevisiae on digestibility and on dairy heifer growth and first-lactation performance.
abstract: Growth and digestibility were examined for heifers limit fed high- (HC; 60%) and low-concentrate (LC; 20%) diets with or without yeast culture (YC) addition in 2 experiments. A third experiment was undertaken to monitor first-lactation production of heifers limit fed HC or LC diets. In experiment 1, 32 Holstein heifers were individually fed at controlled intakes for 133 d to maintain a targeted average daily gain of 0.80 kg/d for all 4 treatments [HC; LC with and without Saccharomyces cerevisiae; Yea-Sacc(1026) (Alltech Inc., Nicholasville, KY), 1 g/kg as fed]. Targeted average daily gain was achieved for all treatments during the individual feeding period (0.80 +/- 0.01 kg/d). Average dry matter intake needed to maintain constant gain was slightly reduced for HC and YC treatments. Reduced dry matter intake and similar targeted average daily gain resulted in a tendency for improved feed efficiency of HC-fed heifers. Skeletal measurements and targeted average daily gain were not affected by concentrate level or YC. The objective of experiment 2 was to elucidate effects of concentrate level and YC on nutrient digestibility. Four young (284.35 +/- 4.51 d) and 4 older (410.28 +/- 2.14 d) heifers were allocated to the 4 treatments used in experiment 1. Heifers fed the HC diet had increased dry matter digestibility (75.67 vs.72.96 +/- 0.72%), and YC addition increased dry matter digestibility (74.97 vs. 73.65 +/- 0.71%). Intake of N and apparent N digestibility were similar for all treatments. High-concentrate diets and YC addition decreased wet and dry matter output of feces. Urine excretion was not different; therefore, total manure output was lower for HC-fed heifers as compared with LC-fed heifers. Results suggest that HC diets can improve feed efficiency without affecting growth when limit fed to dairy heifers. Yeast culture increased dry matter digestibility in HC- and LC-fed heifers; HC diets were more digestible and reduced fecal output, with YC enhancing this effect. In experiment 3, heifers from experiment 1 were group fed the same diets (HC or LC) without YC until parturition, and milk production was measured through 154 d of lactation. Group-fed average daily gain was not different between treatments (HC = 1.11 vs. LC = 1.04 kg/d, SE = +/-0.06 kg/d). Heifers fed the HC and LC diets calved at 23.50 and 23.79 +/- 0.50 mo, respectively. Peak milk was lower and there was a tendency for reduced daily milk and protein yield for primiparous cows fed HC diets from 8 mo of age to the dry/prefresh period (long term), but predicted yields of milk and components were similar in the first 154 d of lactation.
authors.affiliation: Department of Dairy and Animal Science, The Pennsylvania State University, University Park 16802, USA.
authors.forename: G J
authors.initials: GJ
authors.lastname: Lascano
authors.forename: G I
authors.initials: GI
authors.lastname: Zanton
authors.forename: F X
authors.initials: FX
authors.lastname: Suarez-Mena
authors.forename: A J
authors.initials: AJ
authors.lastname: Heinrichs
mesh_terms: D000375:Aging; D000821:Animal Feed / Q000191:economics; D000818:Animals; D002417:Cattle / Q000254:growth & development* / Q000502:physiology; D003365:Costs and Cost Analysis; D004032:Diet / Q000191:economics; D004063:Digestion / Q000502:physiology*; D005243:Feces; D005260:Female; D007774:Lactation / Q000502:physiology*; D008894:Milk Proteins / Q000032:analysis; D009751:Nutritional Requirements; D011247:Pregnancy; D012441:Saccharomyces cerevisiae; D015430:Weight Gain
chemical_list: D008894:Milk Proteins