Low Crude Protein Level Research Articles

The economic implications of bush encroachment on livestock farming in rangelands of Uganda

The objective of this study was to assess the economic implications of shrub encroachment on pastoral rangeland productivity in Mbarara district, in south western Uganda. Sixty pastoral households were surveyed, thirty of which were grazing on cleared farms (with less than 25% of grazing covered by bush) and thirty were grazing on bushy farms (with more than 75% of grazing land covered by bush). The study was a survey and did not involve rigorous experimental work. Results indicated that cleared farms had higher herbage dry matter yield ranging from 1 850 kg ha−1 to 2 230 kg ha−1, compared to a range of 622 kg ha−1 to 1 190 kg ha−1 on bushy farms. Heifers on cleared farms reached puberty earlier and calved relatively earlier (12-30 months) as opposed to 24-36 months on bushy farms. The mean calving rate on cleared farms was higher (33.6%) than 22.6% on bushy farms. Mean milk yield on cleared farms was 3.8 L cow−1 d−1 compared to 2.4 L cow−1 d−1 on bushy farms. Results of body condition score indicated that cattle on cleared range had a higher mean score of 5.8 compared to 4.2 on bushy farms. Mean annual gross income was US$49.393 per cow per annum on cleared farms compared to US$23.351 on bushy farms. Financial efficiency measured by TR/TVC ratio was 1.2 on cleared farms compared to 1.1 on bushy farms. From the findings of the study, it was concluded that shrub encroachment led to reduced herbage DM yield and low levels of crude protein of the pasture, while clearing more than doubled herbage DM production. As a result, animal productivity in terms of milk yield, body condition and reproductive performance were also reduced. Cleared farms were more profitable than bushy ones in terms of gross margins due to higher animal performance and hence higher incomes. The financial efficiency of cleared farms was low due to high costs of shrub control. Shrub encroachment is a serious problem facing pastoral production in Mbarara district and requires adequate attention.

Amino Acid Supplementation of Low-Protein Broiler Diets: 1. Glutamic Acid and Indispensable Amino Acid Supplementation

To maintain optimal growth and carcass development, nutritionists commonly fortify diets low in crude protein (CP) with crystalline amino acids. This experiment sought to apply the ideal amino acid concept and the need of dispensable amino acid nitrogen in poultry by evaluating the effects of lower levels of CP along with amino acid supplementation on broiler performance and carcass development. Lowering dietary CP without amino acid supplementation reduced body weight (BW) gain and increased feed:gain ratio. Supplementation of glutamic acid (Glu) had no effect on feed conversion, but appeared to decrease feed intake and BW gain. Supplementation of indispensable amino acids (IDAA) in addition to Glu to the reduced CP diets improved BW gain and feed:gain ratio, but failed to improve performance to a level achieved by birds fed the positive control diet. Lowering dietary CP, without or with Glu, resulted in reduced carcass yield, increased percentage abdominal fat, and reduced breast meat yield. Birds fed diets supplemented with IDAA + Glu had carcass yields, percentage abdominal fat, and breast meat yields similar to those of birds fed the positive control.This research demonstrates the importance of IDAA in low-CP broilers diets, but failed to show an advantage to Glu supplementation as a dispensable amino acid nitrogen source.

Nitrogen remobilization during the reproductive period in two Brazilian rice varieties

Two rice varieties, IAC‐47 (improved) and Piaui (traditional), were grown in a greenhouse with and without foliar nitrogen (N) supplementation at 10 and 20 days after anthesis (DAA). Changes in N content in shoots (leaves+ sheaths+stalks) and grains were monitored at regular intervals from five days before anthesis (5 DBA) to grain maturity (28 DAA). In the controls of both varieties, the decrease of total N in the shoot was proportional to the increase in total N in the grains. At anthesis, variety IAC‐47 exhibited a higher level of total N in the shoot than variety Piaui (9.32 mg N g‐1 versus 7.22 mg N g‐1). At 28 DAA, IAC‐47 exhibited a lower level of grain crude protein than Piaui (66.5 mg N g‐1 versus 74.7 mg N g‐1). In Piaui, the highest level of protein N in the flag leaf occurred at the time‐1 of anthesis and decreased with grain maturity. In IAC‐47, the protein N of the flag leaf increased parallel to grain N up to 10 DAA. The lower level of crude protein in the grains of IAC‐47 was perhaps caused by the competition between the flag leaf and the grains for plant N. In the controls, the daily rate of N loss in the shoot of Piaui between anthesis and final harvesting was approximately twice that of IAC‐47 (9.94 mg N per day per pot versus 4.66 mg N per day per pot). In the plants receiving supplemental N, the daily rate of N loss in the total shoot was lower in both varieties than in the controls, indicating that when an external source of N was available the plant reduced mobilization of N from its vegetative reserves to fill the grains. Variety IAC‐47, by having been selected in the presence of an abundant supply of external N, has a lower ability to mobilize N from the shoot, resulting in lower N content in the grains than in variety Piaui. Therefore, it may be concluded that plants selected to depend less on external N, are perhaps more efficient in increasing grain protein.

Chemical composition and degradability of Brachystegia spiciformis (musasa) leaves and stems harvested over 4 months from three sites in Zimbabwe

Brachystegia spiciformis terminal shoots (leaf and young stems) samples were harvested from September to December 1994 at Grasslands and Henderson Research Stations and Gwebi College of Agriculture. The samples were analyzed for crude protein (CP), ash, phosphorus, neutral detergent fibre (NDF) and acid detergent fibre (ADF) content. Four rumen cannulated steers were used to determine degradability profiles of dry matter and nitrogen using the nylon bag technique. Significant differences ( P < 0.05) between sites and month of sampling for CP, ash and phosphorus, NDF and ADF were found. The CP content of the samples ranged from 82 to 120 g/kg DM. Lower CP levels were found in stems as compared to the leaf. Ash content ranged from 30 to 45 g/kg DM with samples from Grasslands significantly ( P < 0.05) lower than those from the other two sites. The phosphorus levels were strongly affected ( P < 0.05) by both the site and month of sampling and declined with time. The phosphorus values ranged from 1.23 to 2.67 g/kg DM. The stems were more fibrous than the leaves. From the exponential equation used in the degradability studies the soluble fraction ( a) in the dry matter ranged from 17.6 to 29.9 and there were significant differences ( P < 0.05) between both site and month of sampling. The potentially degradable fraction ( b) in the DM was not affected by either site or month. The effective degradability at passage rates of 0.02, 0.05 and 0.08 passage rates were significantly affected ( P < 0.05) by both the site and month of sampling. The degradability values at 0.02 passage rate were low, ranging from 33.5 to 56.2 and also showed a decline from October to December.

Landscape-Scale Foraging Decisions by Reintroduced Arabian Oryx

We evaluated landscape-level movements of reintroduced Arabian oryx (Oryx leucoryx) in relation to rainfall for 8 years (1982-89). For the first 4 years (1982-85), captive-bred oryx released into habitat devoid of conspecifics demonstrated a distinct shift in movement patterns as foraging conditions deteriorated. Based on mean monthly estimates, during the first 2 months after rain, oryx used large areas (297-724 km 2 ), exhibited low site fidelity (15-32%) overlap between consecutive months), high range expansion (45-62%) new area used each month), and undertook more long distance journeys than expected (P < 0.01). From 2 to 3 months after rainfall, oryx reduced the amount of area used by 86%, increased site fidelity by 72%, reduced range expansion by 29%, and gradually suspended long distance forays. We related this shift to the low nutritive quality of the oryx's primary forage species (Stipagrostis spp.). Once Stipagrostis declined to extremely low levels of crude protein, copper, and phosphorus, the oryx apparently suspended their nutritionally costly searching activities, and instead remained in areas where Stipagrostis was most palatable. In contrast, in years 6 through 8 following their release, the oryx responded to rain with no apparent shift in foraging patterns. Instead, they exhibited less variable and reduced levels of range expansion (10-42%) and area use (180-211 km 2 ). In addition, site fidelity was more consistent on a monthly basis (46-65% overlap),. and long distance movements were more random regardless of the influence of rainfall on the nutritive value or palatability of Stipagrostis. The changes in movement patterns over time were attributed to: (1) a reduction in the oryx's threshold of acceptance for low-quality Stipagrostis; (2) decreased consumption of Stipagrostis and a concomitant increase in browse consumption, and (3) greater knowledge of the landscape. Captive-bred oryx released in years 7 and 8 into the existing reintroduced population reacted to changes in forage nutritive quality caused by rain with a similar shift in foraging patterns as exhibited by the first releases during their first 4 years in the desert. This result emphasizes the relative importance of learned foraging behavior in explaining changes over time in the movement patterns of the oryx. Results of this study indicate that reintroductions of social herbivores should be implemented in ways that enhance the transfer of knowledge from experienced to naive individuals.

Effect of dietary protein levels on growth of Penaeus stylirostris juveniles

The shrimp Penaeus stylirostris is currently produced on a commercial scale in Tahiti and New Caledonia. Both super-intensive (80 animals m−2) and semi intensive (25 m−2) systems are promoted. Locally produced commercial feed contains 380–400 g kg−1 crude protein (CP) without special consideration for environmental impact. The need for a ‘low pollution’ diet implies reconsideration of the optimum dietary protein level for this species. Under experimental conditions, six isoenergetic practical diets ranging from 270 g kg−1 to 440 g kg−1 CP were formulated and fed to satiation for 30 days to juvenile P. stylirostris; average growth rates were between 5.5 and 7.5 g per month with survival rates > 90%. The lowest protein levels 270–310 g kg−1, gave significantly (P < 0.05) poorer growth (5.5 g per 30 days) than was observed with 330–430 g kg−1 CP; 330 g kg−1 CP may be recommended, and as it is lower than levels in diets used currently, there is a possibility of reducing nitrogenous waste. In addition to growth response, protein efficiency ratio, protein productive value and food conversion (feed/gain) all supported a recommended dietary protein level of 330 g kg−1. Future prospects for practical feeds with even lower CP levels are considered.

Red-Billed Teal Foods in Semiarid South Africa: A North-Temperate Contrast

I studied foods consumed by 43 breeding and 24 postbreeding red-billed teal (Anas erythror- hyncha) collected during 1993 on the Nyl River floodplain, South Africa. Upper digestive tract contents were examined relative to sex and reproductive stages on an aggregate percent dry mass basis. Native terrestrial seeds, primarily Panicum schinzii, were the principle dietary items of breeding and postbreeding males and females. Rapid follicular growth/ovulation (RFG/Lay) (13.2%) and postbreeding (13.8%) females ate sig- nificantly more aquatic macroinvertebrates (primarily gastropods) than incubating females (1.6%), and males during RFG/Lay (5.4%), incubation (0.3%) and postbreeding (1.0%). Nutritional analysis of the 9 principal foods consumed indicates that seeds selected contain adequate levels of phosphorus, moderately low levels of crude protein, and calcium levels considerably below needs for egg production. Panicum schinzii has a high fat content relative to the other seeds consumed, but it is deficient in several of the amino acids required for egg production. Red-billed teal are physiologically capable of reproducing while consuming a more herbivorous diet than north-temperate duck species. This may enable them to breed during dry years in semiarid regions. J. WILDL. MANAGE. 60(4):874-881

Chemical Composition and Nutritive Value of Some Wild-Gathered Tropical Plant Seeds

As part of the search for alternative sources of food to alleviate hunger, this study reports the approximate total contents of soluble sugars, starch, and gross energy of nine lesser-known wild-gathered plant seeds. High crude protein levels occurred in Lonchocarpus sericeus (28.03%), Albizia zygia (32.90%), and Gliricidia septum (34.15%). High levels of fat occurred in Entandrophragma angolense (59.30%), L. sericeus (34.15%), and Millettia thonningii (30.66%). Low levels of crude protein but high levels of total carbohydrate were found in Diospyros mespiliformis (77.21% carbohydrate), Daneillia ogea (74.32% carbohydrate), and Afzelia belle (53.96% carbohydrate). Starch contents were high in A. zygia (40.46%), D. ogea (69.62%), and A. belle (51.43%). The seeds with high fat content invariably showed high gross energy levels: E. angolense (30.9 kJ/g), L. sericeus (24.37 kJ/g), and M. thonningii (25.12 kJ/g). The results are compared to those for soya bean and other common staples. It is concluded that these less familiar wild seed plants should not be ignored, but further investigation into possible toxic and antinutrient factors, amino acid patterns, digestibility, and fatty acid composition is still required before recommendations are made.

Plant Structure and the Acceptability of Different Grasses to Sheep

Plant structure should be an important determinant of species acceptability to grazing ungulates functioning under various time-energy constraints. The acceptability of 9 grasses to sheep grazing a secondary grassland community in spring, summer, and autumn in South Africa was related to the following species attributes: plant height, leaf table height, tussock diameter, stemminess, percent leaf, leaf density, percent dry matter (DM), leaf tensile strength, and leaf crude protein (CP). Species acceptability over the grazing season was positively related to tussock diameter (P less than or equal to 0.05) but negatively related (P less than or equal to 0.01) to leaf tensile strength and DM. Discriminant function analysis successfully discriminated between species in different acceptability classes in summer (P less than or equal to 0.05) and autumn (P less than or equal to 0.01) using a combination of plant structure and leaf quality attributes. Correspondence analysis indicated that preferred species were generally short and nonstemmy and had leaves of low DM, low tensile strength, and high crude protein content. Conversely, avoided species tended to be tall and stemmy with a high leaf table height, and had leaves of high DM and tensile strength but low CP levels. It is concluded that, for sheep, acceptability is determined by a combination of plant structure and leaf quality attributes.

Potential of fertilization to improve nutritive value of pricklypear cactus (Opuntia lindheimeri Engelm.)

Pricklypear cactus (Opuntia lindheimeri Engelm.)) an abundant plant in south Texas and north-eastern Mexico, has been used as emergency cattle feed in spite of its relatively low levels of crude protein and phosphorus. A study was conducted to evaluate the influence of nitrogen (N) and phosphorus (P) fertilization on the productivity and nutritive value of pricklypear. Pricklypear was planted on regular 102-cm beds, 46 cm apart in a row and fertilized in the spring for 3 consecutive years. Crude protein levels were increased by 3·1, 4·2, and 4·4 per centage units by the application of 67, 135, and 224 kg N/ha, respectively. Phosphorus content was increased by 0·08 and 0·11 per centage units by the application of 67 and 112 kg P/ha, respectively. Total biomass production was increased approximately five-fold 7 years following planting. These results indicate that N and P fertilization can be used to increase the productivity and nutritive value of pricklypear.

Milk production in early lactation dairy cows given grass silagead libitum: Influence of concentrate energy source, crude protein content and level of concentrate allowance

ABSTRACTThere is increasing interest in how the raw material make-up of concentrates can influence the milk performance of dairy cows. Thus, over two consecutive winters, 54 dairy cows were used to investigate the effects on dry matter (DM) intake, milk yield and its composition of feeding concentrates of diverse energy source (LNDF — 131 g neutral-detergent fibre per kg DM, 492 g starch plus sugars per kg DM; HNDF — 244 g neutral-detergent fibre per kg DM, 293 g starch plus sugar per kg DM) at two formulated crude protein (CP) levels (157v.187 g/kg DM) and three levels of concentrate allowance (9, 11, 13 kg DM). The concentrates were formulated to be of equivalent metabolizable energy concentration (MJ/kg DM) and were offered with silagead libitumfor a 10-week period (weeks 4 to 13 of lactation).Silage intakes were variable but not significantly influenced by concentrate energy source or formulated CP level, except in the 1st year where animals consuming the high CP concentrate ate more silage. Silage DM intake decreased as concentrate allowance was increased with the substitution rate (kg silage DM per kg concentrate DM) increasing as concentrate allowance was increased.Increasing the concentrate allowance effected the expected increases in milk yield. Concentrate energy source did not influence milk yield but the higher CP levels effected a 2-kg increase in milk yield. Feeding of LNDF concentrates depressed milk fat concentration and its yield, the depression being accentuated with each increase in concentrate allowance. The depression in milk fat concentration was negatively correlated with the forage: concentrate ratio of the diet consumed. Furthermore, dietary NDF proportion was shown to account for greater than half of the variation in milk fat concentration. In contrast to the observations made for milk fat, feeding the LNDF concentrates effected an increase in milk protein concentration but only at the lower CP level of the concentrate.

CHEMICAL COMPOSITION AND NUTRITIVE VALUE OF BUCKWHEAT CULTIVARS FOR LABORATORY RATS

Experiments were conducted to determine the nutritive value of selected buckwheats in comparison with common buckwheat or tartary buckwheat. A 21-day, growth trial was conducted in which 42 Spraque-Dawley rats (initial weight 57 g) were randomly assigned to one of seven dietary treatments. Experimental diets contained the buckwheat cultivars, Mancan, Tempest and Tokyo, two unselected forms of common buckwheat (common and CM 169), tartary buckwheat or a casein control. Diets were formulated to supply 10% crude protein by dilution of the test protein with varying levels of a basal diet. An additional 36 rats were utilized in digestibility studies. There was little difference in chemical composition, mineral content, level of indispensable amino acids or digestibility coefficients between selected and unselected varieties of common buckwheat, while tartary buckwheat had lower levels of crude protein, lower indispensable amino acids, higher acid detergent fiber levels and lower apparent digestibility coefficients for dry matter, crude protein and energy. Weight gain and feed conversion efficiency were significantly (P &lt; 0.05) improved for rats fed the selected varieties of buckwheat in comparison with those fed the common or tartary buckwheat. The overall results suggest that the selected cultivars of common buckwheat will support improved animal performance. Key words: Buckwheat, rats, nutritive value, digestibility

Effects of 4,4'-dimethyldiphenyliodonium chloride on performance of growing cattle.

Two 112-d studies were conducted to evaluate effects of the deaminase inhibitor, 4,4'-dimethyldiphenyliodonium chloride, on performance of growing cattle. With diets containing low levels of crude protein (i.e., 11%), 25 ppm of chemical in the diet increased (P less than .05) gain and improved (P less than .05) feed efficiency. Feed intake was not affected. Higher levels of chemical (50 and 100 ppm) produced equivalent responses. With a higher level of dietary crude protein (i.e., 14%) gain and feed efficiency were not improved and some decreases in feed intake were observed. Performance responses resulting from adjustments in ruminal nitrogen transactions to provide more alpha-amino-N depend upon whether the animal needs additional amino acids for maintenance and production. Our data demonstrated that the supply of amino acids can be increased either by adjustment of ruminal nitrogen transactions with a chemical agent or by increasing concentration of dietary protein.

Nutrient Contents of Major Food Plants Eaten by Cattle in the South Texas Plains

From May 1975 to November 1977, whole plant samples of 6 native and 2 introduced grass species, and top pads of 1 browse (pricklypear cactus) species were collected monthly and analyzed for crude protein (CP), P, Na, K, Ca, Mg contents, and digestible energy (DE) to determine their nutritive value as range forage. Digestible energy, CP and P levels, were deficient, especially in winter and early spring for lactating cows but were near to marginal for dry cows. All other elements, except Na, were present at amounts adequate to meet all cattle requirements. Sodium levels were low, but probably would not pose a problem if free choice salt was provided. Any deficiencies may be alleviated by cattle selection of higher quality plants, such as forbs and short-lived annual grasses. Pricklypear cactus had low levels of CP, P, and Na but high levels of estimated DE (2990 K cal/kg); however, pricklypear cactus is high in soluble ash (20%) and if expressed as in vitro digestible organic matter, DE is considerably reduced. These data suggest that protein should be supplemented to lactating cows in winter and early spring while P probably should be supplemented all year. The 7 million hectares of rangeland in the South Texas Plains make up one of the largest native range areas for beef production (cow-calf operation) in Texas (Gould 1975). Ranch enterprises are vital to the area’s economy; however, it is increasingly difficult to make a profit from range operations. The key for ranchers to remain in business is to increase their production of high quality forage. Little research has been conducted on important food plants eaten by cattle on South Texas rangelands (Davis 1952). Cattle production from rangelands depends on rainfall distribution, forage quality, stocking rates, and other management practices. Improving nutritive value of major cattle foods on native range is essential for increasing cattle production; however, range forage nutrition information is limited. This investigation was conducted to determine the nutritive value of major range forage species eaten by cattle grazing on a red sandy loam range site. This study is part of another study, conducted by Everitt et al. (1981), that gives details on botanical composition of cattle diets and range forage availability from September 1976 to November 1977.

Studies on reducing the crude protein content of feeds fed to chicks and young hens (laying stock)

2 rearing trials were carried out on a total of 8550 hybrid chicks (White Leghorn) to investigate in which way food mixtures containing reduced levels of crude protein (supplemented or unsupplemented with amino acids) might influence the growth of chicks and young hens. Decreases from 21.5% to 16.5% in the crude protein content of chicken feed and from 15% to 13% in feeds feed to young hens (greater than 8 weeks of life) did not reduce the live weight of birds at the end of the rearing period to any appreciable extent. No clearly defined differences were found to exist between the different types of feed tested concerning the amount of food and energy consumed per unit of weight gain and the mortality rate among the birds; it was shown, however, that the demand for crude protein per unit of weight gain was clearly reduced in birds reared at the lower crude protein level. For young hens receiving the diet poorer in protein the date when the birds began laying was slightly delayed. Otherwise, no statistically significant differences were found to exist between the young birds fed varying levels of crude protein, concerning the age at 50% laying performance and other parameters that are characteristic of the entire laying period (laying performance, weight of individual eggs, food consumption, mortality, fertilization of hatching eggs, hatchability of eggs). It appears that the feeding of a reduced protein diet to chicks and young hens (laying stock) did not have any detrimental effect on the growth and later laying performance of the birds. Apart from the fact that the demand for protein feeds is considerably reduced during the rearing period the costs of feeding per bird can also be cut down.