Various combinations of cereal chaff and Pinus radiata needles were fed to penned sheep in three experiments. The in vivo digestibility of green needles was estimated to be 36%. Intakes of needles were variable and increased to more than 50% of the total dry matter intake if the chaff component of the diet was restricted to 25% of normal intake. Under these conditions, the needles made a useful contribution to the diet and reduced rates of liveweight loss.The feeding value of pine needles may decrease by about 30% as they age but that of fresh young needles can be greater than those of late summer pasture residues. Therefore, if kept ungrazed for in situ consumption in summer or during drought, when pasture residues are not able to maintain sheep, green pine needles can be valuable either as a substitute for pasture or as a partial supplement.
Tag: sheep
Intake, digestibility and nitrogen utilization by sheep fed with provenances of Calliandra calothyrsus Meissner with different tannin structure
A trial with sheep (housed in metabolic cages, and fitted with ruminal and duodenal cannulas) fed sun-dried forage of two Calliandra calothyrsus provenances (San Ramon —CIAT 22310 and Patulul CIAT— 22316) harvested in sites with contrasting soil fertility was carried out to further define the biological significance of the different chemical structure in the tannin of Calliandra provenances. Six African-type sheep were assigned to one of four treatments (T1: San Ramón grown in Quilichao with infertile soils, T2: Patulul grown in Quilichao with infertile soils, T3: San Ramón grown in Palmira with fertile soils, and T4: Patulul grown in Palmira with fertile soils) arranged in an Unbalanced Simple Crossover Design. Results showed that extractable tannins in Patulul comprised mainly procyanidin subunits, whereas the tannin fraction in San Ramón was composed largely of prodelphinidin subunits. The DM intake and digestibility of Calliandra were greater (P<0.05) with San Ramón than with Patulul. Intake was also greater (P<0.05) with provenances harvested in the site with fertile soil than in the site with acid soils. Absolute and relative values of ruminal escape dietary N in sheep were greater (P<0.05) with San Ramón than with Patulul, which is consistent with laboratory results on tannin astringency. Thus for the first time we have evidence suggesting that the chemical structure of condensed tannins in tropical legumes can have an effect on N utilization by ruminants. The fact that in vivo results on ruminal escape N were in close agreement with results on astringency of extractable condensed tannins from Calliandra provenances validates the use of laboratory astringency tests for screening tropical legumes with tannins for quality traits. = Para poder definir mejor el significado biológico de la diferente estructura química de los taninos de dos procedencias (San Ramon – CIAT 22310 y Patulul – CIAT 22316) de Calliandra calothyrsus se realizó un ensayo de alimentación con ovinos fistulados en el rumen y duodeno, alojados en jaula metabólica y alimentados con forraje seco al sol de las dos procedencias de Calliandra cosechadas en sitios con suelos de fertilidad contrastante. Seis ovinos de pelo tipo Africano se asignaron al azar a 4 tratamientos (T1: -San Ramón cosechada en Quilichao con suelos de baja fertilidad, T2: –Patulul cosechada en Quilichao con suelos de baja fertilidad, T3: -San Ramón cosechada en Palmira con suelos fértiles, y T4: –Patulul cosechada en Palmira con suelos fertiles) dispuestos en un diseño Reversible Simple no Balanceado. Los resultados mostraron que el consumo de MS y la digestibilidad de Calliandra fueron mayores (P<0.05) con la procedencia San Ramón que con la procedencia Patulul, y que el consumo también fue mayor (P<0.05) con el forraje cosechado en el sitio con suelos más fértiles. Los valores absolutos y relativos de proteína del forraje que escapo degradación en el rumen (proteína de escape o sobrepasante) fueron mayores (P<0.05) con la procedencia San Ramón que con Patulul, lo cual es consistente con resultados de astringencia de los taninos de las dos procedencias medida en el laboratorio. Por lo tanto, por primera vez tenemos evidencia que sugiere que la estructura química de los taninos de leguminosas tropicales puede tener un efecto en la utilización de nitrógeno por rumiantes. El hecho de que los resultados de proteína sobrepasante medidos in vivo estuvieran de acuerdo con los resultados de astringencia de taninos de las procedencias de Calliandra determinadas en el laboratorio, valida el uso de estos métodos de astringencia para la selección de leguminosas tropicales por calidad nutritiva.
Pine needle consumption and bark stripping by sheep grazing annual pastures in young stands of widely spaced Pinus radiata and ppinaster.
The consumption of the pine needles and the stripping of bark by sheep grazing annual pastures in three open stands of P. radiata and one of P. pinaster were measured. The P. radiata were four years old and the densities were 250, 500 and 750 trees ha-1. The P. pinaster included two, three and four year-old trees and the density was 440 trees ha1. Needles were eaten immediately after the sheep were admitted and this continued throughout the year. Within ten weeks of the start of winter grazing, sheep stocked at 7–10 ha1 had eaten about half of the accessible needles on both species where densities were less than500 trees ha1. The estimated consumption was about 260 g sheep1 day1 for the P. radiata. Bark stripping then commenced and continued throughout spring and summer on most plots. In some plots at low tree density, bark was stripped from more than 35% of the trees. In denser stands, needle consumption per tree was less and bark was stripped from less than 5% of the trees. Bark damage was most common on the smaller trees, and severity of stripping was negatively correlated with tree size. Of all the trees with bark damage, 22% of the P. pinaster and 14% of the P. radiata had more than half of the stem circumference stripped. A number of these will probably suffer both stem distortion and growth retardation, and some may die. Methods of reducing the incidence of bark damage are discussed.
Potential limitations of natural repellents against early destructive browsing by livestock and game
In a series of pre-screening trials and experiments, 5 different inexpensive and readily available materials were tested for their capability for effectively preventing or reducing destructive browsing by livestock and game on recently established woody perennials. These materials were fluffed-up sheep wool, sisal fibres, fibres from pods of the kapok tree (Ceiba pentandra), extracts from the fruits of Solanum campylacanthum, and the latex of Euphorbia tirucalli. In all trials and experiments, Leucaena leucocephala was used as the test species. Seedlings were planted in April 1986 on contour lines at a spacing of 5×5 m on a 0.7-ha fenced plot at ICRAF’s field station at Machakos, Kenya. All plants were pollarded twice so that they reached a height that allowed goats to reach the terminal shoots at the time of the test. All leader shoots of the test plants, except one to which the repellent was to be applied, were removed before the test, as was alternative browse; grass was slashed. In a first trial, carried out in August 1977, concentrated Solanum fruit extract damaged terminal buds and mature leaves of L. leucocephala. After diluting the extract with water (2 parts extract: 1 part water) no further damaging effect on leaves and buds was observed. All treated parts of the test plant proved tolerant to latex of Euphorbia tirucalli. In a subsequent short-term (24 hours) pre-screening of the 5 repellents in which 3 goats in an enclosure of 5×10 m were used as test animals, all but the latex of Euphorbia tirucalli showed promise as effective repellents, so the latex was excluded from subsequent experiments. The remaining 4 materials were then exposed to 2 consecutive larger-scale experiments. In spite of the deliberately increased stocking rate (8 goats on 0.7 ha and 5 goats on 0.45 ha) and the removal of all alternative browse, all 4 repellents proved to have a retarding effect on browsing. However, fluffed-up sheep wool, and to a lesser extent, fibres from pods of the kapok tree, gave the most promising results.