Effect of a controlled-release urea supplement on rumen fermentation in sheep fed a diet of sugar cane tops (Saccharum officinarum), corn stubble (Zea mays) and King grass (Pennisetum purpureum)

Multifarious feed additives on lamb performance on Kuwait farms

Background and Aim

A change in the livestock feeding strategy is of utmost importance for the stability of animal health and sustainable livestock productivity to overcome the problem of subsiding the environmental effects of sheep production. Supplementing dietary feed with safe and efficient additives provides optimal animal performance and maximizes productivity. This study aimed to assess the effects of adding various feed additives to lamb rations for optimizing feed efficiency in weaned lambs for meat production in Kuwait.

Materials and Methods

The feed additives, namely, ammonium chloride, urea, algae, fishmeal, and humic acid, were investigated on the physical performance of lambs for their effect on body weight, length, height, and waist length. The total feed consumption rate and feed efficiency were also measured. Each treatment comprising five healthy lambs was randomly allocated into six treatments comprising 30 lambs. The six treatments were the basal ration supplemented with ammonium chloride (50-100 g/day/head), urea (30 g/day/head), fishmeal (35 g/day/head), algae (Spirulina platensis) powder (50 g/day/head), humic acid (2.5 g/day/head), control group with only basal ration. The study was conducted for around 27 months and the data were recorded once in 2 weeks.

Results

The results indicated a positive elevation in the physique of lambs with all tested additives, showing an affirmative insignia for lamb fattening. The growth parameters in terms of augmented length, height, and waist length of lambs' bodies amplified significantly with ammonium chloride and fishmeal supplement, while the other additives reported a non-significant increment. The feed consumption was significantly elevated for ammonium chloride, algae, and fishmeal supplementation, while humic acid was recorded the least. Concerning feed efficiency of young lambs, fish meal and ammonium chloride were reported best, followed by urea. In contrast, algae and humic acid exhibited a non-significant effect on feed efficiency.

Conclusion

This study exposed noteworthy influence on a lamb body's performance with the addition of fish meal and ammonium chloride in lamb rations, trailed by urea and algae.

A Meta-Analysis of the Effects of Slow-Release Urea Supplementation on the Performance of Beef Cattle

Slow-release urea (SRU) is a coated non-protein nitrogen (NPN) source for ruminant nutrition. This study applied a meta-analytic technique to quantify the effect of a commercial SRU (Optigen^®, Alltech Inc., Nicholasville, KY, USA) on the performance of beef cattle. Data were extracted from 17 experiments and analysed using the random-effects model to estimate the effect size of SRU on dry matter intake (DMI), crude protein intake (CPI), live weight gain (LWG) and feed efficiency (FE) of growing and finishing beef cattle. There was no effect of feeding SRU on the overall DMI and CPI of beef cattle. Dietary inclusion of SRU improved the overall LWG (+92 g/d/head) and FE (+12 g LWG/kg DMI/head) of beef cattle. Notably, SRU supplementation in growing cattle exhibited a better improvement on LWG (130 vs. 60 g/d/head) and FE (18 vs. 8 g LWG/kg DMI/head) compared with finishing cattle. Moreover, SRU showed consistent improvements on the LWG and FE of beef cattle under several study factors. Simulation analysis indicated that positive effects of SRU on LWG and FE improved profitability through reduction in feed cost and reduced the emission intensity of beef production. These results indicate that SRU is a sustainable NPN solution in beef cattle production.

Influence of dietary slow-release urea on growth performance, organ development and serum biochemical parameters of mutton sheep

Eighty Dorper × thin-tailed Han cross-bred non-castrated male lambs [mean body weight (BW), 25.87 ± 1.06 kg] were randomly allocated to one of five different concentrations of slow-release urea (urea phosphate, UP). The feed consisted of an equal amount of concentrate diet and roughage; the concentrate feed was formulated to be isoenergetic and isonitrogenic and contained 0%, 1%, 2%, 4% and 8% UP (UP0.0, UP1.0, UP2.0, UP4.0 and UP8.0, respectively) as a replacement for soya bean meal. Feed intake, BW, average daily gain (ADG), feed utilisation efficiency (FUE), absolute and relative organ weights and biochemical and histopathological parameters were measured. Feed intake, BW, ADG and FUE significantly decreased in the group receiving UP8.0 (p < 0.05), but no difference was found among the other groups (p > 0.05). Quadratic equations were developed between the UP dosage in the concentrate feed and ADG or FUE (r²  = 0.973 for ADG and r²  = 0.761 for FUE) to determine the appropriate dosage of UP given the desire to maximise either ADG or FUE, the appropriate dosage (feed concentration) was calculated as 2.01% UP to achieve the greatest ADG or 2.13% UP to achieve the best FUE. The relative weight of the liver (% BW) in the UP2.0 groups was significantly greater than that of UP0.0 (p < 0.05), and the relative weight of the intestine in the UP8.0 was significantly greater than that of UP0.0 (p < 0.05); the relative weight of the carcass, heart, spleen, lung, kidney, rumen, reticulum, omasum and abomasum did not differ among treatments (p > 0.05). The UP8.0 treatment significantly increased serum phosphorus levels (p < 0.05) and decreased the levels of alkaline phosphatase, glucose and calcium (Ca) compared with the lower UP dosage (p < 0.05). No histopathological differences were found in either hepatic tissues or renal tissues among treatments. Dietary UP as a replacement for soya bean in concentrate feeds for mutton sheep should not exceed 4%, as higher dosing may cause malnutrition and mineral disorders.

Benefits of different urea supplementation methods on the production performances of Merino sheep

The impact of urea supplementation of sheep feed was examined in two experiments. In Experiment 1, 48 8-month-old Merino wethers were randomised into three groups by liveweight and each group was fed one of three diets: (1) untreated oaten chaff hay; (2) hay treated with urea in-paddock (pre-experiment); or (3) hay treated with a 2% urea solution using a feed mixer. In Experiment 2, 48 4-month-old Merino ewes were randomised into three groups and each group received one of the following roughages: (1) untreated oaten chaff hay, (2) hay treated with a 2% urea solution in a feed mixer, or (3) a 20 kg urea lick block. Both experiments lasted 40 days, and sheep liveweight (kg), average feed intake (g/day), average daily gain (ADG) and body condition score (BCS) were recorded. Ruminal fluid and blood samples were collected on days 20 and 40 from animals in Experiment 1. Sheep supplemented with additional urea had a greater average dry matter (DM) intake (Experiment 1, P = 0.038; Experiment 2, P = 0.001), ADG (Experiment 1, P = 0.043; Experiment 2, P = 0.041) and average final liveweight (Experiment 1, P = 0.048), compared to sheep receiving no additional supplementary urea. On both days 20 and 40 in Experiment 1, blood analyses revealed that urea supplemented sheep had elevated levels of urea, creatine kinase and total protein (P <0.05). Urea supplementation most likely influenced blood urea and total protein concentrations, as supplemented sheep had an increased crude protein intake (through increased feed intake of urea treated roughage with a higher crude protein percentage). By providing additional urea, the DM intake of sheep in both experiments was increased and offers a practical strategy when providing supplementation to sheep. The practice can benefit sheep production by increasing the nutritional value and digestibility of low energy crop stubbles, when fed over dry summer months to help maintain BCS.

Effect of a controlled-release urea supplementation on feed intake, digestibility, nitrogen balance and ruminal kinetics of sheep fed low quality tropical forage

Four ruminally cannulated crossbred sheep (25+/-3.4kg BW) were divided into a 4x4 Latin square design to measure the effects of controlled-release urea supplement (CRUS). The basal diet consisted of 60% sugar cane tops (Saccharum officinarum), 30% full plant corn stubble (Zea mays), and 10% King grass (Pennisetum purpureum). Feed intake, digestibility, N balance and in situ ruminal kinetics were studied with four diets, D1 (control), D2, D3 and D4, which included the ratios of 100:0%, 90:10%, 80:20% or 70:30% of basal diet with CRUS. Results showed DMI differences (P<0.05) for D4 (822g per day) versus D1, D2 and D3 (580, 659 and 700g per day, respectively). N retention increased (P<0.05) for D4 (35.69g per day) versus D1, D2 and D3 (9.29, 6.85 and 19.10g per day, respectively). In vivo N digestibility was greater (P<0.05) in D4 (79.63%) than in D1 (57.57%). In vivo digestibility of DM, OM, GE, cellulose and hemicellulose was similar among the four groups. Digestibility of cell walls in D4 was higher (P<0.05) at 74.06% versus 67.78% in D1. In situ DM digestibility showed differences (P<0.05) among all diets at 9, 12, 24 and 48h of incubation. Potentially digestible fiber, 52.61%, was higher (P<0.05) in D4 versus 31.00% in D1. Indigestible fiber, 35.29%, was lowest (P<0.05) in D4 compared to 81.51% in D1. Digestion rate constant (k(d)) was different (P<0.05) between the experimental diets and control. Passage constant (k(p)) was different (P<0.05) between all diets (0.036/h in D4 to 0.081/h in D1). True digestibility was higher (P<0.05) in D4 (44.64%) compared to D1 (19.55%), but in D2 (24.54%) and D3 (28.22%) there was no difference. Cellulose in situ digestion rate, the potentially digestible fiber, was higher (P<0.05) in D3 (42.74%) as compared to D1 (22.50%). Time of disappearance of cellulose in D4 (14.79h) was less (P<0.05) than in D1 (24.03h), however there was no difference between D1 and D2. Hemicellulose in situ digestion was different (P<0.05) between D3 (45.48%) and D1 (23.61%). Digestion rate was higher (P<0.05) between D3 and D4 as compared to D1. Passage rate was different (P<0.05) between D4 (0.033/h) and D1 (0.018/h). True digestibility in D3 (34.84%) and D4 (34.62%) was higher (P<0.05) than that in D1 (20.06%) and D2 (25.86%). Half-time disappearance (t(1/2)) for hemicellulose was higher (P<0.05) in D1 (62.36h) than in D3 (28.00h) and D4 (20.64h). This study demonstrated that low quality forages at 70% of the total diet can be efficiently utilized by sheep when controlled-release urea supplementation is 30% of the feeding regime.