Plant litter is an important nutrient pool in grassland ecosystems. Management practices affect litter quality and may affect nutrient dynamics in pastures by altering the rates of nutrient mineralization and immobilization. The effect of management intensity on litter decomposition and nutrient disappearance was evaluated in a litter bag study on continuously stocked 'Pensacola' bahiagrass (Paspalum notatum Flü gge) pastures growing on Pomona and Smyrna sands. Treatments were three management intensities: Low (40 kg N ha 21 yr 21 and 1.3 animal units [AU, one AU 5 500 kg live weight] ha 21 stocking rate [SR]), Moderate (120 kg N ha 21 yr 21 and 2.7 AU ha 21 SR), and High (360 kg N ha 21 yr 21 and 4.0 AU ha 21 SR). Litter relative decomposition rate (k) was greater for High (0.0030 g g 21 d 21 ) than Low (0.0016 g g 21 d 21 ). Litter N, acid detergent insoluble N (ADIN), and lignin concentrations were greater for High than the other intensities at the end of the 168-d incubation period because of faster decomposition of soluble compounds. Across management intensities, approximately one-half of litter N remaining at the end of the incubation period was bound to acid detergent fiber (ADF). Net N mineralization through 128 d of incubation was only 200 to 300 g kg 21 of total N. Increasing management intensity resulted in faster litter turnover and greater nutrient release, but nutrient release from litter was small and significant quantities of nutrients were immobilized even under the most intensive management.

Diaper dermatitis may result after repeated or prolonged contact of skin with urine and feces. A hairless mouse model was used to elucidate the role of urine in this process. The results of this work suggest that an important function of urine in the etiology of diaper dermatitis is to increase the pH of the diaper environment by breaking down urea in the presence of fecal urease. This rise in pH increases the activities of fecal proteases and lipases, which can damage skin. Urine can also increase the permeability of diapered skin to irritants and can directly irritate skin when exposure is prolonged.

Plant litter is an important pathway of nutrient return to the soil in grazed swards, but the effects of pasture management on litter mass and composition are not well understood. This research evaluated the effect of management intensity, defined in terms of N fertilization and stocking rate (SR), on litter mass, deposition rate, and chemical composition in continuously stocked 'Pensacola' bahiagrass (Paspalum notatum Flü gge) pastures growing on Pomona and Smyrna sands. Treatments were three management intensities: Low (40 kg N ha 21 yr 21 and 1.3 animal units [AU, one AU 5 500 kg live weight] ha 21 SR), Moderate (120 kg N ha 21 yr 21 and 2.7 AU ha 21 SR), and High (360 kg N ha 21 yr 21 and 4.0 AU ha 21 SR). Greater management intensity resulted in less litter mass on the pasture early in the growing season and more litter mass later in the season. Rate of litter deposition was generally greatest for High and ranged between 23 and 40 kg organic matter (OM) ha 21 d 21 compared with 13 to 30 kg OM ha 21 d 21 for Low and Moderate management intensities. Increasing management intensity from Low to High resulted in greater litter N (14.1 vs. 22.9 g kg 21 ) and P (0.8 vs. 1.3 g kg 21 ) concentrations and lesser C:N (f40 vs. 22), C:P (649 vs. 433), and lignin:N (5.8 vs. 4.4) ratios. More intensive pasture management was associated with greater litter deposition rate and litter quality than less intensive management, suggesting a larger nutrient contribution from litter in intensively managed swards.

Most of the research efforts involving the bovine gastrointestinal microbiota have focused on cattle's forestomach, particularly the rumen, so information concerning the bovine fecal microbiota is more scarce, especially in young beef cattle. The present study was performed to evaluate the ruminal and fecal microbiotas of beef calves as they reached the end of their nursing phase. A total of 18 Angus cow/calf pairs were selected and assigned to one of two treatment groups for the last 92 days of the calves' nursing period, as follows: 1) calves were supplemented with concentrate in a creep feeding system; or 2) control group with no supplementation of calves. After 92 days, ruminal and fecal samples were individually obtained from calves in both groups, and their microbiotas were evaluated using 16S rRNA gene sequencing. Ruminal samples were predominated by Prevotella (18 to 23% of the total bacterial abundance), regardless if calves received supplementation or not; however, in the feces, Prevotella was only the seventh most abundant genus (0.6 to 2.1% of total bacterial abundance). Both the rumen (P = 0.01) and the feces (P = 0.05) of calves that received supplementation had greater abundance of Firmicutes. In addition, calves that were supplemented had lower abundance of Fibrobacteres (P = 0.03) in their rumens. Regardless if the calves were supplemented or not, Faith's Phylogenetic Diversity index (P � 0.007) and total concentration of short chain fatty acids (P < 0.001) were both greater in the rumen than in the feces of calves. In summary, the ruminal and fecal microbiotas of weanling beef calves were considerably distinct. Additionally, supplementation with creep feed caused some significant changes in the composition of the gastrointestinal microbiota of the calves, especially in the rumen, where supplementation caused an increase in Firmicutes and a decrease in abundance of Fibrobacteres.

Early weaning of calves (Bos spp.) increases pregnancy rates of beef cows; however, there is little information on nutritional management of the weaned calf on pasture. This research evaluated the effect of concentrate supplementation level on performance of early weaned (90 d of age) beef calves grazing annual ryegrass (Lolium multiflorum Lam.)–rye (Secale cereale L.) mixtures on Adamsville (uncoated, hyperthermic, Aquic Quartzipsamment) and Pomona (sandy, siliceous, hyperthermic Ultic Alaquod) sands. Three levels of supplement (10, 15, and 20 g kg−1 of calf body weight [BW]) were evaluated in a completely randomized design with three replicates. The concentrate contained 146 and 700 g kg−1 of crude protein (CP) and total digestible nutrients (TDN). Pastures were rotationally stocked with a 7‐d grazing and 21‐d rest period. Two calves were assigned as testers to each pasture, and additional animals were used to maintain a similar herbage allowance across treatments. There was no effect of concentrate supplementation level on herbage mass, accumulation, allowance, or nutritive value. Calf average daily gain (ADG; 0.74–0.89 kg), liveweight gain (LWG) per hectare (950–1320 kg), and stocking rate (SR; 5.5–6.5 animal units [AU] ha−1) increased linearly, and forage intake decreased linearly (18–11 g kg−1 BW) as concentrate rate increased. Grazing time was 284, 230, and 234 min d−1 (linear and quadratic effects) for the 10, 15, and 20 g kg−1 BW supplement treatments, respectively. Feeding systems with modest levels of supplementation (10 g kg−1 BW) of calves grazing cool‐season grasses are practical options for early weaned calves during winter in the southeastern USA.