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At least 667 records · Page 37Linked to original sources
PubMed1998

Effects of fiber from tropical corn and forage sorghum silages on intake, digestion, and performance of lactating dairy cows.

Tropical corn silage was compared with sorghum silage as a basal forage in the diets of high producing dairy cows. Sorghum and tropical corn silages were each included in place of ground corn at incremental concentrations in the experimental diets. Eight separate diets were fed, four diets containing each silage ranging in forage neutral detergent fiber (NDF) from approximately 25 to 31% and ranging in total NDF from approximately 41 to 45%. Diets were arranged in a 2 x 4 factorial design and were fed to lactating cows (n = 24; pretrial mean milk production = 39 kg/d; body weight = 656 kg; and days in milk = 81). As concentrations of dietary NDF increased, intake and milk production decreased linearly. The impact of dietary NDF on intake was greater for diets based on tropical corn silage than for diets based on sorghum silage. Energy intake and milk production were reduced, but cows consumed more fiber when challenged with higher dietary concentrations of fiber. The in vitro rate and extent of digestion of dietary samples were correlated with intake response. The rate of in vitro fiber digestion was slower for samples that contained tropical corn silage than for samples that contained sorghum silage. In vivo digestibility measurements were influenced by intake and dietary composition. Results of this trial indicated that sorghum silage can have equal or slightly greater nutritional value than tropical corn silage when these forages are fed at equal concentrations of dietary fiber.

Animal Feed↗
PubMed1999

Degradability of forage proteins by in situ and in vitro enzymatic methods.

The overall objective of these two studies was to evaluate the efficacy of using the proteolytic enzyme from Streptomyces griseus to estimate concentrations of ruminally degradable protein (RDP) in a wide array of forages. In the first study, alfalfa and prairie hays that previously had been evaluated in vivo for RDP were incubated in a replicated 3 x 3 factorial combination of enzyme concentrations (6.6, 0.66, and 0.066 activity units/ml of incubation medium) and incubation times (2, 4, and 48 h). Two treatment combinations (6.6 activity units for 4 h and 0.066 activity units for 48 h) yielded respective RDP estimates for alfalfa and prairie hay that were close to the known in vivo values. In the second study, 20 diverse forages were evaluated for RDP by using the in situ technique. These forages also were evaluated for RDP with the two enzyme concentrations identified in the first study, but incubation times were expanded to include 1, 2, 3, 4, and 5 h at the high concentration and 24, 30, 36, 42, 48, and 54 h at the low concentration. At the high enzyme concentration, r2 statistics from linear regressions of enzymatic estimates of RDP on corresponding estimates obtained by the in situ procedure were high (r2 > or = 0.898) at all incubation times; in addition, slopes (range = 0.88 to 1.00) and intercepts (range = -9.4 to 3.5%) approached unity and 0, respectively. At the lower enzyme concentration, r2 statistics were still good (> 0.81), but slopes (0.59 to 0.67) and intercepts (18.5 to 21.9%) for all incubation times did not meet the respective goals of unity and 0.

Animal Feed↗
PubMed2005

A neural network model of foraging decisions made under predation risk.

This article develops the cognitive-emotional forager (CEF) model, a novel application of a neural network to dynamical processes in foraging behavior. The CEF is based on a neural network known as the gated dipole, introduced by Grossberg, which is capable of representing short-term affective reactions in a manner similar to Solomon and Corbit's (1974) opponent process theory. The model incorporates a trade-off between approach toward food and avoidance of predation under varying levels of motivation induced by hunger. The results of simulations in a simple patch selection paradigm, using a lifetime fitness criterion for comparison, indicate that the CEF model is capable of nearly optimal foraging and outperforms a run-of-luck rule-of-thumb model. Models such as the one presented here can illuminate the underlying cognitive and motivational components of animal decision making.

Animals↗
PubMed1976

[Vitamin E activity of stored forages and incidence of myopathy in calves].

Two experiments to study nutritional muscular dystrophy (N.M.D.) in calves were conducted in northern Ontario, where the disease is prevalent. In the first experiment, ninety Shorthorn cows were used. They were divided into three groups and fed the following forages during the winter of 1972-1973. Group I - Silage. Group II. - Heated-air-dried hay. Group III. - Field-dried hay. Chemical analysis of the forage during storage showed that the silage had a higher tocopherol content than the other two forages. This higher content had a direct effect on plasma tocopherol concentrations in the cows, since tocopherol levels were found to be higher in the group fed silage than in the other two groups. The highest mortality rate-eight dead calves-was in the group fed heated-air-dried hay; one calf died in each of the other two groups. Hence, it is evident that the severity of N.M.D. symptoms in calves is directly linked with the quantity of selenium or vitamin E ingested. The substances act synergistically to protect against the disease. In a second experiment, a herd of forty-seven Shorthorn cows, some of which had calves with N.N.D. and some of which had healthy offspring, were studied to measure the activity of serum creatine phosphokinase. The dams were found to have the same C.P.K., whether or not their calves suffered from N.M.D.

Animal Feed↗
PubMed2002

[Spatial heterogeneity of grassland pattern under grazing and forage condition].

Spatial heterogeneity and spatial autocorrelation of grassland pattern under grazing and forage condition were studied using semivariance analysis and fractal method. The results indicate that vegetation patterns are scale-dependent. Spatial heterogeneity and spatial autocorrelation of foraged grassland are more complex than grazed grassland and have more scale regions which determined by different fractal characteristics. Spatial autocorrelation of species diversity on foraged grassland was weaker, in another word, gradient of species diversity(beta-diversity) was smaller. Spatial heterogeneity of grazed grassland was simplified by grazing, because topographical variation was partly wiped out.

China↗
PubMed2002

[Echolocation sound waves, morphological features and foraging strategies in Hipposideros pratti].

Studies on the echolocation sound waves in different states (flying and hanging), morphological features and ecological processes (foraging strategies, foraging habitat and diet type) of Hipposideros pratti showed that H. pratti had CF (constant frequency)-FM (frequency modulated) echolocation sounds. There were some differences in dominant frequency (caused by Doppler compensating effect), pulse repetition rate, pulse duration and interpulse interval between the bats at flying and hanging. The dominant frequency, FM bandwidth, pulse duration and interpulse interval were lower, while the pulse repetition rate and duty cycle were higher at flying than at hanging. All the differences indicated that H. pratti could adopt specific echolocation sounds to adapt to specific environments and conditions to detect, approach and capture their preys successfully. On the basis of echolocation sound and field observation, it was concluded that H. pratti might search the preys at flying in the period of insect fastigium, and after the period, it might search the targets at hanging. The foraging habitat was near the tree crowns, and the preys consisted mainly of relatively large insects, such as beetles.

Animals↗
PubMed2004

[Effects of accumulated temperature and planting density on tillering dynamics of forage rye].

Using equal design method, a field experiment was carried out at Wuqiao field station of China Agricultural University in Hebei Province to study the effects of different accumulated temperature before winter and planting density on tillering dynamics of forage rye (Secale cereale L.). The results showed that the tiller number per plant was affected by sowing date and seed density. In the prophase of forage rye, the tiller number per plant was mainly influenced by sowing date; while in the anaphase, it was mainly determined by seed density. Generally, earlier and fewer sowing norm could raise the tiller number in individual plant. In the prophase, metaphase, or anaphase of forage rye, the tiller number per unit area decreased with the postponing of sowing date, and increased with the increase of sowing norm. The sowing date and sowing norm had decisive effect on the number of effective stem per unit area. Suitable population structure was dependent on the increase of effective stem number per plant under the conditions of earlier sowing, and of effective stem number per unit area under the conditions of later sowing.

Regression Analysis↗
PubMed2004

[Extensive grazing and designed feeding with supplemented legume forages on natural grassland].

Livestock needs to be fully stuffed and fed well. Eating-well can compensate eating-full, and can rapidly increase the body weight of livestock, shorten its feeding period, enhance its production, and protect natural grassland from overgrazing. A designed feeding based on extensive grazing on natural grassland by supplementing rich crude protein-contained forage might be a new trend for optimizing the animal husbandry on grassland. Adding 20% legume forages to the diets for wethers could make the live body weight get a 40%-65% increase, achieving 52-61 kg in October extending to December. Forage production, animal nutrition and animal production were the three relatively primary factors for grassland management while focusing on grazing. Some terms such as eating-well, eating-well degree, eating-full, eating-full degree, extensive grazing and designed feeding were also defined respectively in this paper.

Animal Feed↗
PubMed2005

Effects of stream hydraulic conditions on foraging strategies of false dace, Pseudorasbora parva, in the lentic ecosystem.

The effects of current velocity on the foraging behavior of false dace, Pseudorasbora parva, were examined in a zero velocity (stagnant) condition, and at four flow rates (5, 7, 11 and 16 cm per second). In stagnant water, the fish displayed a cruise-searching pattern, but they used a drift-feeding foraging tactic in flowing water. The shape of the transverse field of reaction field was elliptical in the stagnant condition, whereas their downward regions were restricted under the flowing conditions. The fish had a blind spot oriented directly in front of their reaction field. Although the relative swimming speed (with considering the against current velocity) increased with increasing flow velocity, the absolute search speed (ignore the against current velocity) showed about 1.2 fish body length per second at stagnant water and low flow velocity. The results of feeding rates showed stop-and wait (driff-feeding) foraging strategy is more efficient in flowing water because prey drift directly towards the fish and prey easily detected.

Animals↗
PubMed1991

Drought increases forage nitrate and cyanide.

To investigate drought-associated increases in concentrations of nitrate and cyanide in animal forage, we compared forage nitrate and cyanide in 1986-87 (annual rainfall 33 in) to nitrate and cyanide in a drought (1988 and 1989; annual rainfall 20 and 27 in, respectively). Fifteen to 20% of the nitrate and cyanide samples from 1986-1987 had sufficiently high concentrations to be of concern (3000 ppm nitrate, 20 ppm cyanide as submitted). Only 4-6% of the 1986-1987 samples had concentrations sufficiently high to produce acute respiratory distress (13,000 ppm nitrate, 50 ppm cyanide as submitted). During 1988 sample numbers had more than doubled, suggesting increased concern for the possibility of nitrate or cyanide intoxication and yielding parallel increases in the number of samples with elevated nitrates or cyanides. By 1989, 25-33% of the samples had concentrations of health concern with respect to either nitrate or cyanide, while 14-19% had concentrations sufficiently high to produce acute respiratory signs. Shortages of forage caused by a 2-y drought were further exacerbated by nitrate and cyanide increases in that feed. Future efforts should concentrate on controlling groundwater nitrate and delivery of nitrate to the plant root-systems.

Animals↗
PubMed1987

Ammoniated forage toxicosis in calves.

Two calves developed a CNS syndrome characterized by hyperesthesia, tremors, and incoordination while nursing dams that had been feeding on ammoniated forage. To increase digestibility, intake, and nitrogen content, low-quality forages were ammoniated at a rate of 3% dry weight. However, a CNS syndrome of unknown cause has been observed in cows and calves nursing cows that have ingested ammoniated forage. Serum electrolytes, glucose, and blood differentials of the 2 calves in this report were normal. However, the older calf had high serum and CSF ammonia concentrations. Both calves, sedated with acepromazine and given thiamine injections, were clinically normal 12 hours later.

Ammonia↗
PubMedDate not supplied

Determination of nitrate in forages by using selective ion electrode: collaborative study.

Each of 10 collaborating laboratories analyzed 4 blind duplicate pairs of forage samples for nitrate, by using a potentiometric method. Two forage controls and a 100 000 mg KNO3/L standard were also provided. Nitrate was extracted into an aqueous Al2(SO4)3 solution containing 70 mg KNO3/L and quantitated with a nitrate-selective electrode. Standards were prepared using extracting solution as diluent. Nitrate concentrations in forage samples ranged from less than 0.50 to 4.35% KNO3. Repeatability coefficients of variation (CVo) ranged from 1.74 to 3.61%, and reproducibility coefficients of variation (CVx) ranged from 6.92 to 7.66%. Mean recovery of a 0.55% KNO3 spike was 94.5%. The method has been adopted official first action.

Animal Feed↗
PubMed1985

Serum selenium concentrations and glutathione peroxidase activities in cattle grazing forages of various selenium concentrations.

In cows from 15 dairy herds (n = 210), serum selenium (Se) concentrations ranged from 0.021 to 0.789 microgram/ml, whereas 0.05 to 0.40 microgram/ml is the reported range for adequate serum Se concentrations in cattle. Serum Se concentrations of dairy cattle appeared to follow a geographic distribution pattern. On the basis of herd mean serum Se concentrations, adequate serum Se concentrations were found in cattle from only 1 of 5 herds grazing forage in the geographic area classified as Se deficient for cattle. Adequate mean serum Se concentrations were found in cattle from 4 of 5 herds located in geographic areas described as having variable forage Se concentrations (Se-marginal areas). Of the 10 herds from these 2 areas, there were only 2 herds in which 95% of the cattle had serum Se concentrations in the Se-adequate range (0.05 to 0.40 microgram/ml). In 2 selected neighboring farms in the Se-deficient area, cattle in 1 herd had adequate serum Se concentrations and cattle in the other herd had less than adequate serum Se concentrations (less than 0.05 microgram/ml). Therefore, more cattle are at risk of developing Se-deficiency disease than is commonly believed and forage of neighboring farms may have different Se concentrations. Serum Se concentrations (up to 0.789 microgram/ml) correlated with glutathione peroxidase enzyme activity; this serum Se concentration (0.789 microgram/ml) is approximately 6.2 times higher than previously reported in dairy cattle. Therefore, RBC glutathione peroxidase activity may be useful in determining the diagnosis of chronic Se toxicosis.

Animal Feed↗
PubMed2026

Transcriptomic and proteomic signatures underlying nymphal adaptation and foam production in the forage pest Mahanarva spectabilis.

The spittlebug Mahanarva spectabilis (Distant, 1909) (Hemiptera: Cercopidae) is an important pest of forage grasses in South America, where its nymphs cause pasture damage by feeding on xylem sap and producing a characteristic foam that protects them against environmental stressors. To investigate the molecular basis of this adaptation, we integrated RNA-seq analysis of nymphs with LC-MS/MS proteomics of the Batelli gland, the primary source of foam secretion. De novo assembly of 100,666 unigenes revealed broad functional diversity, with strong representation of detoxification enzymes (CYP450s, GSTs, UGTs, carboxylesterases), transporters and ion pumps, cuticle proteins, and stress- and immunity-related genes. Nearly 16% of loci exhibited alternative splicing, particularly within detoxification, chemosensory and osmoregulatory gene families, highlighting evidence of transcriptomic variability. Signal peptide and secreted protein predictions identified 168 high-confidence candidate secreted proteins, including detoxification enzymes, proteases, structural proteins and immune-related factors, several of which are consistent with antimicrobial and surfactant-related functions. Proteomic profiling of the Batelli gland confirmed 500 proteins, enriched in chaperones, metabolic enzymes, detoxification pathways and osmoregulatory components, with the most abundant proteins corresponding to Hsp70 chaperones, ATP synthases, cuticle proteins and carbonic anhydrases. Together, these results provide an integrative transcriptomic and proteomic overview for M. spectabilis nymphs, highlighting genes and proteins associated with xylem feeding, foam production and responses potentially related to environmental stress tolerance. This comprehensive dataset not only advances the understanding of spittlebug biology but also identifies candidate molecular targets that may inform innovative strategies for controlling nymphal stages and mitigating spittlebug damage in forage systems.

Animals↗
PubMed1998

Posture and support use of Old World monkeys (Cercopithecidae): the influence of foraging strategies, activity patterns, and the spatial distribution of preferred food items.

A common objective in field studies of positional behavior is to establish functional links between locomotion, body size, habitat use, foraging strategies, and maintenance activities. In contrast, there has been relatively little effort to examine posture in a similar, comparative context. Although various studies have shown that particular postures are employed in specific contexts, the theory which could provide the basis for understanding posture on a more general level has not been explicitly stated. This is particularly true for primates lacking specializations such as prehensile tails, claws for clinging, or adaptations for forelimb suspension. Consequently, there are few a priori reasons for predicting postural differences among generalized arboreal quadrupeds. Six sympatric cercopithecid monkeys were studied for 14 months in the Ivory Coast's Tai Forest to determine if more general relationships do exist between posture and other aspects of behavior. The results demonstrate that the postural diversity with these primates can, to varying degrees, be understood within the context of differences in the spatial distribution of preferred food items, activity patterns, support use, and foraging strategies.

Animals↗
PubMed2005

Tool use in insect foraging by the chimpanzees of Ngogo, Kibale National Park, Uganda.

Chimpanzee tool use for resource acquisition has been reported at numerous research sites. The chimpanzees of the Kibale Forest, western Uganda, have not previously been observed to use tools in foraging for insects. Here I report the first observation of tool use by the chimpanzees of the Ngogo community of Kibale National Park, Uganda, in insect foraging. Three adult females, one adolescent male, and one juvenile male were observed making and using tools to probe into a fallen dead tree to collect insect and wood pieces. I discuss the importance of this observation, and the behavioral similarities with chimpanzees from other sites.

Animals↗
PubMed2004

An ill child among mid-Holocene foragers of Southern Africa.

The skeletal remains of an infant from a southwest South African rock shelter at Byneskranskop show pervasive abnormalities that are consistent with the effects of hypertrophic (hyperplastic) rickets. Diagnostic features include beading of the costochondral junctions of the ribs, flaring and tilting of the metaphyses, and cupping of the distal ulna, as well as general skeletal hypertrophy. With an uncalibrated accelerator mass spectrometry (AMS) radiocarbon date of 4820 +/- 90 BP (TO-9531), this is a very early instance of the condition, among foragers whose environment and diet make dietary shortages of active vitamin D or dietary calcium improbable. Carbon and nitrogen stable isotope ratios indicate a mixed diet, including marine as well as terrestrial protein. Solicitous care maintained the sick infant to an estimated age of 3.5-5 months; it was buried in a manner like that of other deceased group members. This case suggests that if infanticide was practiced, it was an option only during the immediate perinatal period, when this infant would have appeared normal. This is consistent with documentation of infanticide practices among historic foragers from southern Africa.

Age Determination by Skeleton↗
PubMed2001

Linking structural variability in long bone diaphyses to habitual behaviors: foragers from the southern African Later Stone Age and the Andaman Islands.

The cross-sectional distribution of cortical bone in long bone diaphyses is highly responsive to mechanical loading during life, yet the relationship between systemic and localized influences on skeletal structure remains unclear. This study investigates postcranial robustness throughout the body among adults from two groups of foragers with different patterns and modes of mobility, to determine whether there is evidence for upper vs. lower body localization of skeletal robustness. The samples used for this comparison are from the southern African Later Stone Age (LSA; n = 65, male = 33, female = 28) dating from ca. 10,000 to 2,000 B.P., and 19th century indigenous Andaman Islanders (AI; n = 36, male = 17, female = 16). The LSA were highly mobile foragers who did not exploit offshore marine resources. In contrast, the AI had tightly constrained terrestrial, but significant marine, mobility. Geometric properties of cortical bone distribution in the diaphyses of the clavicle, humerus, femur, tibia, and first metatarsal are compared between the samples, providing a representation of skeletal robustness throughout the body. Multivariate ANOVA shows the AI to have significantly stronger clavicles and humeri, while the LSA femora, tibiae, and first metatarsals are stronger than those of the AI. These patterns, in which upper and lower limbs show biomechanical properties that are consistent with habitual behaviors, suggest localized osteogenic response. Although postcranial robustness appears to be correlated with overall limb function, the results suggest that more proximal elements within the limb may be more responsive to mechanical loading.

Adult↗