Particle size distribution and chemical composition of total mixed rations for dairy cattle: water addition and feed sampling effects.

Four dairy farms were used to determine the effects of water addition to diets and sample collection location on the particle size distribution and chemical composition of total mixed rations (TMR). Samples were collected weekly from the mixing wagon and from 3 locations in the feed bunk (top, middle, and bottom) for 5 mo (April, May, July, August, and October). Samples were partially dried to determine the effect of moisture on particle size distribution. Particle size distribution was measured using the Penn State Particle Size Separator. Crude protein, neutral detergent fiber, and acid detergent fiber contents were also analyzed. Particle fractions 19 to 8, 8 to 1.18, and <1.18 mm were judged adequate in all TMR for rumen function and milk yield; however, the percentage of material>19 mm was greater than recommended for TMR, according to the guidelines of Cooperative Extension of Pennsylvania State University. The particle size distribution in April differed from that in October, but intermediate months (May, July, and August) had similar particle size distributions. Samples from the bottom of the feed bunk had the highest percentage of particles retained on the 19-mm sieve. Samples from the top and middle of the feed bunk were similar to that from the mixing wagon. Higher percentages of particles were retained on >19, 19 to 8, and 8 to 1.18 mm sieves for wet than dried samples. The reverse was found for particles passing the 1.18-mm sieve. Mean particle size was higher for wet than dried samples. The crude protein, neutral detergent fiber, and acid detergent fiber contents of TMR varied with month of sampling (18-21, 40-57, and 21-34%, respectively) but were within recommended ranges for high-yielding dairy cows. Analyses of TMR particle size distributions are useful for proper feed bunk management and formulation of diets that maintain rumen function and maximize milk production and quality. Water addition may help reduce dust associated with feeding TMR.

Antioxidant activity in plasma and rumen papillae development in lambs fed fermented apple pomace.

The effect of fermented apple pomace (FAP) on animal health, antioxidant activity (AA), hematic biometry (HBm) and the development of ruminal epithelium were investigated in a study with 24 finishing lambs (BW = 25.4 ± 3.3 Kg). Lambs were grouped by sex (12 male and 12 female) and fed (n = 6 per group of treatment) a basal fattening diet (Control diet, T1) or the basal diet supplemented to include 10.91% of fermented apple pomace (FAP diet, T2). The animals were kept 56 d in individual metabolic cages, with ad libitum access to water and feed. Two blood samples were collected from each animal on d 0, 28, and 56 to determine AA in plasma and hematic biometry (HBm). Four samples of ruminal tissue were taken postmortem to evaluate the development of ruminal epithelium based on the length (LP) and width (WP) of papillae. AA and HBm data were analyzed with a mixed model (fixed effects: diet, sampling, sex, and their interaction; using the experimental unit nested in the effect of the diet as the random effect). LP and WP were analyzed with a hierarchical model, as simple and nested effects in the sampling site, where the fixed effects were the diet and the sex of the animal and their interaction. There was an effect of diet on AA, which was higher (P < 0.06) in T2 vs. T1 at 56 d (24.34 vs. 21.79 mM Fe2). Leukocytes increased (P < 0.05) from 7.52*10(3) ± 1.29*10/(3)µL to 9.14*10(3) ± 1.24*10(3)/µL in all the animals in the experiment, with a marked increased (P < 0.05) at 28 d after beginning of the feeding period, with values within the normal range for this species and without effect of the diet (P > 0.05) for the other indicators of HBm. Males' LP was higher in T2 than in T1 (P < 0.05). It was concluded that the use of FAP in the diets of finishing sheep reaped benefits on animal health and the development of rumen epithelium by improving antioxidant activity in plasma and stimulating the growth of papillae.

Effect of repeated suboptimal chlorate treatment on ruminal and fecal bacterial diversity.

The minimal effective dose of sodium chlorate as an intervention to reduce the carriage of pathogenic bacteria in food-producing animals has not been clearly established. The effect of low-level oral chlorate administration to ewes was assessed by comparing the diversity of prominent bacterial populations in their gastrointestinal tract. Twelve lactating crossed Pelibuey and Blackbelly-Dorper ewes (average body weight, 65 kg) were randomly assigned (four per treatment) to receive a control treatment (TC; consisting of 3 g of NaCl per animal per day) or one of two chlorate treatments (T3 or T9; consisting of 1.8 or 5.4 g of NaClO3 per animal per day, respectively). Treatments were administered twice daily via oral gavage for 5 days. Ruminal and fecal samples were collected daily, starting 3 days before and ending 6 days after treatment, and were subjected to denaturing gradient gel electrophoresis of the 16S rRNA gene sequence amplified from total population DNA. For ruminal microbes, percent similarity coefficients (SCs) between groups varied from 23.0 to 67.5% and from 39.4 to 43.3% during pretreatment and treatment periods, respectively. During the treatment period, SCs within groups ranged from 39.4 to 90.3%, 43.3 to 86.7%, and 67.5 to 92.4% for TC, T3, and T9, respectively. For fecal microbes, SCs between groups varied from 38.0 to 85.2% and 38.0 to 94.2% during pretreatment and treatment periods, respectively. SCs for fecal populations during treatment were most varied for TC (38.0 to 67.9%), intermediate for T9 (75.6 to 92.0%), and least varied for T3 (80.6 to 90.6%). Heterogeneity within and between groups provided no evidence of an effect of chlorate treatment on ruminal or fecal microbial populations.