Establishment techniques affect productivity,nutritive value and atmospheric N2 fixation of two sunn hemp cultivars

Nitrogen fertilization is a common practice for sustaining forage production in forage systems in southeastern United States. Warm-season annual legumes may be an alternative forage to warm-season perennial grasses that do not require N fertilization. Sunn hemp (Crotalaria juncea L.) is a fast-growing, warm-season annual legume native to India and Pakistan. The objective of this 2-year study was to assess the herbage accumulation (HA), atmospheric N₂ fixation (ANF) and nutritive value of sunn hemp. Treatments were the factorial arrangement of two sunn hemp cultivars (“Crescent Sun” and “Blue Leaf”), three seeding rates (17, 28 and 39 kg seed/ha) and seed inoculation (inoculated or non-inoculated seeds), distributed in a randomized complete block design with four replicates. Crescent sun had greater HA (3,218 vs. 1764 kg DM/ha) and ANF (41 vs. 25 kg N/ha). Blue leaf had greater crude protein (CP) (188 vs. 176 g/kg) and in vitro digestible organic matter (IVDOM) concentrations (564 vs. 531 g/kg) than crescent sun. Non-inoculated seed had greater CP than inoculated seed, 188 and 177 g/kg, respectively, and inoculation did not affect HA. Intermediate seeding rate (28 kg/ha) decreased HA (2002 kg DM/ha), while HA from high and low seeding rates (17 and 39 kg/ha, respectively) did not differ (2,863 and 2,615 kg DM/ha respectively). Planting non-inoculated crescent sun at 17 kg/ha seeding rate is a feasible management practice to produce sunn hemp in subtropical regions; however, inoculation should always be recommended for proper establishment.     

Methane emissions and δ13C composition from beef steers consuming increasing proportions of sericea lespedeza hay on bermudagrass hay diets

An experiment was conducted to evaluate the effects of different proportions of ‘Au Grazer’ sericea lespedeza [SL, Lespedeza cuneata (Dum. Cours.) G. Don], a legume rich in condensed tannins (CT), on nutrient intake and digestibility, and to estimate methane (CH₄) emissions and ¹³C isotopic composition (δ¹³C_CH4) from beef steers consuming a forage-based diet. Twenty-five Angus-crossbred steers were distributed in a randomized complete block design (344 ± 48 kg initial BW), and randomly assigned to one of five treatments: 0SL, 25SL, 50SL, 75SL, and 100SL, diets containing 0%, 25%, 50%, 75%, and 100% of SL hay, respectively, mixed with ‘Tifton-85’ bermudagrass hay (Cynodon spp.). The study was carried out for two experimental periods of 21-d each. The statistical model included the fixed effect of treatment and random effects of block, experimental period, and their interaction. Apparent total tract digestibility of crude protein, neutral detergent fiber, and acid detergent fiber was linearly decreased (P < 0.001) by the inclusion of SL. No effects were observed for total CH₄ emissions per day, nor for CH₄ relative to organic matter intake or digestible organic matter with the inclusion of SL. However, emission of CH₄ in relation to intake of CT was affected by treatment (P < 0.001). A linear (P < 0.001) decrease and a quadratic effect (P < 0.001) were observed for δ¹³C of diets and gas, respectively, in which diets and enteric CH₄ with greater inclusion of SL were more depleted in ¹³C. Moreover, the difference in δ¹³C between diets and gas (Δδ¹³C) had a linear decrease (P = 0.001) with the inclusion of SL. The model developed to predict the C₃ proportions in the enteric CH₄ fitted to predicted values (P < 0.0001). Therefore, greater proportions of SL resulted in lesser CH₄ emission when CT intake was considered and the isotopic composition from enteric CH₄ was able to predict the contribution of SL in the emissions.     

Seeding strategies of bahiagrass and pintoi peanut affect pasture establishment under weed competition

Pintoi peanut (Arachis pintoi Krapov. & W.C. Greg.) is a warm‐season perennial legume with potential for use in grass–legume mixtures in Florida; however, limited information exists about its establishment in mixtures with bahiagrass (Paspalum notatum Flügge). The objective of this experiment was to evaluate the establishment of bahiagrass cv. “Argentine” and pintoi peanut cv. “Amarillo” as monocultures or mixture. The experiment was conducted in Ona, FL, from June to October of 2014 and 2015. Treatments were a split‐plot design of seeding strategies (bahiagrass monoculture, pintoi peanut monoculture or bahiagrass‐pintoi peanut mixtures; main plots) and two N fertilization strategies (30 or 80 kg/ha N; 30N and 80N; subplots), with four replicates. Measurements of plant density and frequency were taken every 4 weeks after seeding. Ground cover and herbage mass (HM) measurements were taken 112 days after seeding. Pintoi peanut ground cover was affected by seeding strategy × N level interaction. Ground cover was greater with 80N than 30N when pintoi was seeded in monoculture (3.6% vs 1.5% respectively) but not when it was seeded with bahiagrass (2.1%). There was no effect of seeding or N strategy on pintoi peanut proportion in HM (1.4%). Bahiagrass ground cover was not affected by seeding or N strategy (15.9%); however, its proportion in the HM was greater in 80N than 30N (12.1% vs 9.4% respectively). Mixed seeding did not negatively affect the establishment of bahiagrass and pintoi peanut and greater N fertilization levels improved some establishment parameters, with no negative effect for pintoi peanut.     

Bahiagrass response and N loss from selected N fertilizer sources

The increasing cost of commercial fertilizers and environmental problems associated with improper fertilization management have prompted the need to re‐examine commercial N sources that can effectively supply N to pastures while minimizing N losses. This 3‐year study evaluated the effects of selected N sources on bahiagrass (Paspalum notatum Flügge) responses, soil properties and N losses. Treatments consisted of a factorial combination of 6 N sources [(i) ammonium nitrate (AN), (ii) ammonium sulphate (AS), (iii) urea (U), (iv) urea treated with Agrotain (U + Agrotain), (v) SuperU and (vi) ammonium sulphate nitrate] and 3 N levels (0, 60 or 120 kg ha^?1 year^?1), replicated three times. Bahiagrass dry‐matter yield (DMY), crude protein (CP) concentration, N uptake and recovery were not affected by N source, with the exception of AN that resulted in reduced DMY in 2010 compared with the other sources. Bahiagrass DMY, CP concentration, N uptake and recovery increased linearly as N levels increased. Nitrogen fertilization showed no effect on soil pH or soil N accumulation. Soil pore‐water N concentrations from treatments fertilized with N were similar to the control plots indicating no threat to the environment. At the N levels evaluated in this study, selection of N source should be based on the fertilizer cost.     

The Impact of Organic Biofertilizer Application in Dairy Cattle Manure on the Chemical Properties of the Soil and the Growth and Nutritional Status of Urochroa Grass

The management of nitrogen (N) fertilization in pasture has great importance for yield and maintenance of Brazilian livestock. The objective of this study was to evaluate soil chemical attributes, shoot dry weight yield (SDWY) and roots dry weight yield (RDWY), nutritional status and nutritive value of Mulato II Urochloa grass that received organic biofertilizer rates as N source. The treatments were arranged in completely randomized blocks, were fertilized with six organic biofertilizer rates (0, 25, 50, 100, 200, and 400 m³ ha^?1) and five replicates during four harvest cycles. There was a quadratic response in the accumulated SDWY for up to a rate of 400 m³ ha^?1 and RDWY with 330 m³ ha^?1 of organic biofertilizer. The organic biofertilizer influenced the soil chemical attributes and foliar nutrient concentration. However, only the crude protein content presented a quadratic response, and neutral detergent fiber and acid detergent fiber levels were not affected by the influence of organic biofertilizer applied to the soil.     

Effects of dietary yeast cell wall on faecal bacteria and fermentation products in adult cats

This study evaluated the effects of increasing concentrations of spray‐dried yeast cell wall (YCW) in diets for healthy adult cats on apparent nutrient digestibility and on bacterial composition and fermentation products in the stool. Fourteen cats with an average weight of 4.40 ± 1.05 kg and an average age of 6.2 ± 0.54 years were used and assigned to treatments in an unbalanced randomized block design (by experimental period) with two blocks and three or four cats per diet in each block. Treatments included: control (0% YCW), 0.2% YCW, 0.4% YCW and 0.6% YCW, totalling seven animals per experimental diet. We found that YCW did not affect body weight, nutrient and food intake, faecal production, faecal score, faecal pH or urine output (p > .05). Regarding faecal bacteria, we observed a linear reduction in Clostridium perfringens, a quadratic reduction in Escherichia coli, and linear increases in Bifidobacterium spp. and Lactobacillus spp. (p < .05) with the inclusion of YCW. Regarding the faecal short‐chain fatty acid profile, butyrate, valerate, total biogenic amines, putrescine, cadaverine and histamine increased linearly (p < .05) with the inclusion of YCW. It was concluded that in healthy adult cats, consumption of YCW modulates the faecal bacterial populations, with an increased presence of beneficial bacteria and a reduction in some potentially pathogenic bacteria. It was concluded that YCW modulated the levels of fermentation products. There was an increase in fermentation products coming from carbohydrate metabolism, an important effect that can potentially benefit the intestinal health of cats. The consumption of YCW also increased the fermentation of nitrogen compounds, which have not yet been defined as deleterious or beneficial. The fermentability of carbohydrates and nitrogen compounds may be associated. Therefore, YCW may cause rapid fermentation of both classes of compounds by enhancing the fermentability of one class.     

Vitamin D metabolism in dogs and cats and its relation to diseases not associated with bone metabolism

Due to the presence of receptors in the cells of numerous body tissues, vitamin D is associated with several physiological functions that go beyond calcium and phosphorus homoeostasis and control of bone metabolism in the body. In humans, several studies have associated lower vitamin D concentrations with numerous diseases, such as cancer, heart disease, autoimmune diseases and infectious diseases, and also with an increase in the total mortality rate of the population. Recently, this nutrient started to gain importance in veterinary medicine, and several articles have shown a correlation between low vitamin D status and diseases unrelated to bone metabolism. The present review aims to highlight the recent publications that investigated this relationship, bringing the evidence that exists so far in dogs and cats.     

Effects of incorporating cowpea in a subtropical grass pasture on forage production and quality and the performance of cows and calves

The increasing cost of N fertilizer has stimulated an interest in sourcing protein from warm‐season legumes among beef cattle producers in the tropical/subtropical areas of the world. The objective of this study was to evaluate effects of two strategies of incorporating cowpea [Vigna unguiculata (L.) Walp.] into bahiagrass (Paspalum notatum Flügge) pastures on the herbage characteristics and performance of grazing cow–calf pairs. The study was conducted in Ona, Florida, USA, from May to August in 2007 and 2008. Experimental units were 1·0 ha. Treatments were bahiagrass pasture alone (control), 50:50 bahiagrass–cowpea pasture (cowpea), bahiagrass pasture with a cowpea creep grazing area (0·1 ha, creep grazing) and bahiagrass pasture with a creep‐fed concentrate [(creep feeding; 10 g kg^?1 body weight (BW)]. The cowpea pastures had lower herbage mass [HM, 1·8 vs. 3·7 t ha^?1] and herbage allowance [HA, 0·8 vs. 1·4 kg DM kg^?1 live weight (LW)] compared with the other treatments. Cowpea had greater CP (CP, 160 g kg^?1) and in vitro digestible organic matter (IVDOM), (600 g kg^?1) than bahiagrass (110 and 490 g kg^?1 respectively); however, cowpea HM was only 0·9 t ha^?1 in May and 0·7 t ha^?1 in June, but it did not persist in July and August. Calves receiving the creep feeding treatments had greater average daily gain (0·8 vs. 0·7 kg d^?1) than calves in other treatments. Further research is necessary to exploit the superior nutritive value of cowpea in grazing systems in the south‐eastern USA.     

Total tract nutrient digestion and milk fatty acid profile of dairy cows fed diets containing different levels of whole raw soya beans

Whole oilseeds such as soya beans have been utilized in dairy rations to supply additional fat and protein. However, antinutritional components contained in soya beans, such as trypsin inhibitors and haemagglutinins (lectins) may alter digestibility of nutrients and consequently affect animal performance. The objective of the present experiment was to quantify the effect of different levels of whole raw soya beans in diets of dairy cows on nutrient intake, total tract digestion, nutrient balances and milk yield and composition. Sixteen mid to late‐lactation cows (228 ± 20 days in milk; mean ± SD) were used in four replicated 4 × 4 Latin square design experiment with 21‐d periods. Cows were assigned to each square according to milk yield and DIM. The animals were randomly allocated to treatments: control (without soya beans addition; CO), WS9, WS18 and WS27, with addition of 9%, 18% and 27% of whole raw soya bean in diet on a dry matter (DM) basis respectively. All diets contained identical forage and concentrate components and consisted of maize silage and concentrate based on ground corn and soya beans at a ratio of 60:40. There were no differences in OM, CP, NDF and NE_L intakes (kg/day and MJ/day) among the treatments (p > 0.05). However, DM and NFC intakes were negatively affected (p = 0.04 and p < 0.01, respectively) and ether extract (EE) intake was positively affected (p < 0.01). Total tract digestion increased linearly with whole raw soya beans for EE (p < 0.01) and NDF (p = 0.01). The excretion (kg/day) of digested soya beans grains increased linearly according to addition of whole raw soya beans. However, the nutritive characteristics of excreted grains were not altered. Milk (kg), milk lactose (kg) and protein (kg) yield decreased linearly (p < 0.01, p < 0.01 and p = 0.04, respectively) milk fat content (%) increased linearly (p < 0.01) with whole raw soya beans inclusion. Increasing addition of whole raw soya beans affected milk fatty acid profile with a linear decrease of cis‐9‐trans 11CLA and total saturated FA; and linear increase of total unsaturated and C_18:3 FA. Energy balance was positively affected (p = 0.03) by whole raw soya beans as well as efficiency of NEL milk/DE intake (p = 0.02). Nitrogen balance and microbial protein synthesis were not affected by whole raw soya beans. Increasing doses of whole raw soya beans decreased dry matter intake and milk yield, however, led to an increase of unsaturated acids in milk and higher milk fat concentration.     

Predictive equations of maintenance energy requirement for healthy and chronically ill adult dogs

Maintenance energy requirement (MER) is the energy amount necessary for dogs to maintain their weight and body condition. Some factors can influence the MER, such as gender, age, neutering status and also diseases. The present retrospective study aimed to evaluate MER of adult dogs with several diseases and compare with the MER of healthy adult dogs, observing the influence of parameters such as body condition score (BCS), neutering status, gender, age, diagnosis and type of food on MER of these dogs. A total of 165 adult dogs with weight changes of ≤5% were included and divided in groups according to diagnosis. Mean MER for healthy dogs was 86.09 kcal/BW^0.75, which differed from NRC and FEDIAF recommendations for inactive adult dogs (p = .047). Lowest MERs were of the endocrinopathies (78.52 ± 19.32 kcal/BW^0.75), orthopaedic diseases (59.71 ± 19.30 kcal/BW^0.75) and neurologic diseases (78.83 ± 32.66 kcal/BW^0.75) groups. Gastrointestinal diseases (99.59 ± 20.36 kcal/BW^0.75), orthopaedic diseases (59.71 ± 19.30 kcal/BW^0.75) and neoplasia (95.61 ± 21.02 kcal/BW^0.75) groups were the only groups that differed from the mean MER of healthy adult dogs. Regarding BCS, for each increasing point in a 9-point scale, there was a decrease of 9.8 kcal/BW^0.75 on MER, independent of diagnosis (p < .0001; r² = .55). There was no difference regarding breed size gender and age, but neutered dogs presented lower MER (p = .031). Based on data obtained from the present study, it can be concluded that it is necessary to consider BCS, age, neutering status and diagnosis when calculating MER, both in healthy dogs and chronically ill dogs.