Seasonal Variations in Voluntary Intake and Apparent Digestibility of Forages in Goats Grazing on Introduced Leymus chinensis Pasture
The nutrient composition of pasture, voluntary intake and digestibility of diet ingested by goats grazing on an introduced Leymus chinensis pasture were measured across spring (May), summer (July), autumn (October) and winter (March). In each season, 12 Inner Mongolian Cashmere goats (6 wethers and 6 does with an average live weight of 22.2±1.3 kg and 19.5±0.8 kg, respectively) were used to graze on a 2 hectares size paddock. Diet selection was observed and the plant parts selected by grazing goats and whole plant L. chinensis were sampled simultaneously. The alkane pair C32:C33 and C36 were used to estimate intake and digestibility, respectively. The results showed that the plant parts selected by goats had higher crude protein (CP) and lower acid detergent fiber (ADF) and neutral detergent fiber (NDF) than the whole plant, especially in the autumn and winter. The voluntary intake of dry matter (DM), CP, ADF, NDF, and metabolizable energy (ME) by goats was highest in summer (p<0.05). The goats ingested more CP, ME, and less ADF in spring than in autumn (p<0.05). The intakes of DM, CP, and ME were lowest in winter (p<0.05). There were significant differences in nutrient intake between wethers and does in each season, except for the ADF and ME intake per metabolic weight (LW0.75). The nutrient digestibilities were higher in spring and summer, and decreased significantly during the autumn and winter (p<0.05). Goats, especially wethers, had a relative constant NDF digestibility across seasons, however, the apparent digestibility of CP in both wethers and does, decreased to negative values in winter. The grazing goats experienced relatively sufficient nutrients supply in spring and summer, and a severe deficiency of CP and ME in winter.
Effect of Season on the Chemical Composition and Nutritive Value of Shrub Foliage (Cotoneaster spp.) of Sub-Alpine Pasture of Kashmir Valley
The present study was conducted to find out the variation in the chemical composition and nutritive value of Cotoneaster spp. in two different seasons viz. summer (June) and late autumn (November). The samples (leaves and soft twigs) were analyzed for proximate composition, fibre fraction, calcium and phosphorus. Nutritive evaluation in terms of DMD, DMI, DCP and energy content in terms of ME and TDN were estimated using regression equations. The study revealed that CP decreased by 6.8% from June to November, while DCP decreased by 9.83%. However, CF, NDF, ADF, ADL increased by 7.88%, 21.66%, 47.33% and 32.71%, respectively. DMD, DMI, TDN and ME decreased by 15.46%, 17.67%, 10.9% and 18.74%, respectively. Calcium content showed increasing trend while phosphorus content showed decreasing trend from June to November. The Relative feed quality index (RFQi) decreased from summer (120.65) to autumn (83.78). Thus, Cotoneaster pastures in summer are more nutritious and more readily consumed by grazing animals than in late autumn, hence animals must be given more time for grazing in late autumn than for summer to compensate the loss of nutrients. undesirable plants. Sub-alpine pastures of Kashmir valley house the immense wealth of flora. Cotoneaster plants form one of the important grazing resources available in the sub-alpine pastures of the Kashmir valley. The importance of Cotoneaster in the lives of Kashmiri people dates back to medieval period when its bark was used to make brown dyes (Lawerence, 1895). The importance of Cotoneaster plants has the of terms its medicinal properties as the plant has antibacterial (Kanaani et al ., 2015), antioxidant, anticancer and hepatoprotective activities (Sokkar et al ., 2013), but the plant’s potential as the grazing resource has not been elucidated so far. The present study is one such step towards understanding the nutritive potential of cotoneaster plant.
Effects of faecal n-alkane recovery in estimates of diet composition
The outer surfaces of plant leaves and stems are covered with a waxy layer, a considerable fraction of which comprises n-alkanes which are not digested and, therefore, can be used as markers in animal nutrition studies. Most plant species have a characteristic pattern of n-alkane concentrations in their cuticular wax and this enables the diet composition to be estimated by comparison with the pattern of the n-alkanes in faeces. N-alkane recovery in faeces was determined in a digestibility trial involving three different diets given to four goats, six cows and five calves. The validity of using n-alkane markers to determine diet composition was examined in in vivo feeding trials with goats and cows. The recovery of the odd chain length n-alkanes increased linearly with n-alkane chain length, with no significant differences between treatments. Estimates of diet composition were affected by the faecal n-alkane recovery rate. N-alkanes in plant cuticular wax can be used as natural markers for estimating diet composition, but a recovery factor should be used to correct for incomplete recovery in faeces. More research is needed to extend the findings to wider ranges of diets, animals, environmental conditions and physiological and reproductive states.