El objetivo del presente trabajo fue evaluar la capacidad de predicción de las ecuaciones de calibración desarrolladas mediante NIRS (espectroscopía de reflectancia en el infrarrojo cercano) sobre ...muestras secas y molidas, para estimar la calidad fermentativa de ensilados de girasol. Un total de 52 muestras de ensilados procedentes de diferentes ensayos de silos de laboratorio realizados en el CIAM (Centro de Investigacións Agrarias de Mabegondo), cuyo espectro NIRS se registró sobre muestras secas en estufa y molidas. Las muestras en estado fresco fueron analizadas por métodos de referencia. Se determinó el pH, ácido láctico, ácido acético, etanol, nitrógeno amoniacal y nitrógeno soluble. Las calibraciones NIRS fueron desarrolladas utilizando regresión por mínimos cuadrados parciales modificada, realizando la regresión entre los datos espectrales y los de referencia. La capacidad predictiva de las ecuaciones obtenidas osciló entre excelente y buena, mostrando coeficientes de determinación de validación cruzada (r2vc) iguales o superiores a 0.88. Los valores del índice RPD para todos los parámetros estudiados fueron iguales o superiores a 3.0, por lo tanto, las ecuaciones de calibración obtenidas sobre muestras secas y molidas pueden utilizarse satisfactoriamente para predecir la calidad fermentativa de ensilados de girasol en análisis de rutina.
Background: Small-scale dairy systems contribute to mitigate rural poverty as they provide a stable source of incomes to farming families, and also contribute with over 30% of national milk ...production. However, the dependency on external inputs affects their profitability and sustainability, which added to difficult agroclimatic conditions and limiting management factors as high stocking rate in pastures. It is therefore necessary to evaluate feeding strategies better adapted to conditions in these systems to improve cattle diets based on quality forages reducing external dependency and thus, costs. A means to increase herbage yields in pastures is overseeding with annual fast-growing cereals. Objective: The objective was to evaluate the productive performance of dairy cows on two feeding strategies based on grazing, and the analysis of costs in small-scale dairy systems in the highlands of central Mexico. Methodology: Eight Holstein cows were used on continuous day grazing (8 h/day) under on-farm research with a double cross-over design. Treatments ere: continuous intensive grazing of Kikuyu grass pastures (KY) or Kikuyu grass overseeded with rye (KYCEN) from 6:00 to 16:00 h, plus 4.5 kg DM/day of commercial concentrate. Two groups of four cows balanced for days in milk and daily milk yield were formed, and each group randomly assigned to one of the treatment sequences: KY-KYCEN-KY y KYCEN-KY-KYCEN, with three experimental periods of 14-day each, with 10 days for adaptation to diets and four days for sampling. Pastures were assessed with a split-plot design. Records were for milk yield and composition, live weight and body condition. A partial budget analysis was performed to compare income and feeding costs. Results: There were no statistical differences (P>0.05) in productive performance, with mean 3.5% fat corrected milk yield of 17 kg/cow/day, with 36.6 g/kg, 28.5 g/kg and 43.4 g/kg for milk fat, protein and lactose respectively. There were no significant differences (P>0.05) between treatments for sward height or herbage mass, but there were significant differences (P<0.05) for DM and OM content between treatments, and for CP, NDF, ADF, IVDMD, and EM (P<0.05) between periods. Implications: In the face of complex agroecological scenarios for small-scale dairy systems, it is necessary to assess forages better adapted for these conditions as the inclusion of a fast growing cereal as rye to increase pasture production and increase the forage base in the diets with farm resources as Kikuyo grass, in order to increase the profitability of farms. Conclusions: Since there were no statistical differences in the productive performance of dairy cows, or in economic performance, the conclusion is that treatment KY is the recommended option for this season. Treatment KYCEN requires expenditures in seed and labour, so that it is not a viable option for small-scale dairy systems in this season.
An on-farm participatory study was undertaken to assess changes over seasons on the availability, botanical and morphological composition, and nutritive value of herbage from two pastures in ...small-scale dairy systems in the highlands of central Mexico. One pasture (TF-33) was originally sown with tall fescue, while the second pasture (KY) was naturally invaded by Kikuyu grass; both associated with white clover and over-sown in winter with annual ryegrass. Sampling was every 28 days for a year. Variables were sward height, net herbage accumulation, soil cover, tiller density, chemical composition, and in vitro digestibility. A split-plot design was used. Sward height was greater for KY. There were no differences (p > 0.05) for herbage accumulation. TF-33 was 53% live tissue, 30% dead tissue, and 17% other plant material, whilst KY was 50% live tissue, 30% dead tissue, and 18% other plant material. TF-33 showed a higher leaf to stem proportion, while stem was higher in KY. Kikuyu grass and annual ryegrass performed better when associated with TF-33 than in KY pasture. Seasonal changes significantly affected sward height, herbage mass and net herbage accumulation, whereby TF-33 performed better than KY in winter. The multispecies association of diverse grasses and legumes may be complementary at different times of the year due to plasticity among species, and is a feasible option for small-scale dairy systems.
Background: Small-scale dairy systems contribute to mitigate rural poverty as they provide a stable source of incomes to farming families, and also contribute with over 30% of national milk ...production. However, the dependency on external inputs affects their profitability and sustainability, which added to difficult agroclimatic conditions and limiting management factors as high stocking rate in pastures. It is therefore necessary to evaluate feeding strategies better adapted to conditions in these systems to improve cattle diets based on quality forages reducing external dependency and thus, costs. A means to increase herbage yields in pastures is overseeding with annual fast-growing cereals. Objective: The objective was to evaluate the productive performance of dairy cows on two feeding strategies based on grazing, and the analysis of costs in small-scale dairy systems in the highlands of central Mexico. Methodology: Eight Holstein cows were used on continuous day grazing (8 h/day) under on-farm research with a double cross-over design. Treatments ere: continuous intensive grazing of Kikuyu grass pastures (KY) or Kikuyu grass overseeded with rye (KYCEN) from 6:00 to 16:00 h, plus 4.5 kg DM/day of commercial concentrate. Two groups of four cows balanced for days in milk and daily milk yield were formed, and each group randomly assigned to one of the treatment sequences: KY-KYCEN-KY y KYCEN-KY-KYCEN, with three experimental periods of 14-day each, with 10 days for adaptation to diets and four days for sampling. Pastures were assessed with a split-plot design. Records were for milk yield and composition, live weight and body condition. A partial budget analysis was performed to compare income and feeding costs. Results: There were no statistical differences (P>0.05) in productive performance, with mean 3.5% fat corrected milk yield of 17 kg/cow/day, with 36.6 g/kg, 28.5 g/kg and 43.4 g/kg for milk fat, protein and lactose respectively. There were no significant differences (P>0.05) between treatments for sward height or herbage mass, but there were significant differences (P<0.05) for DM and OM content between treatments, and for CP, NDF, ADF, IVDMD, and EM (P<0.05) between periods. Implications: In the face of complex agroecological scenarios for small-scale dairy systems, it is necessary to assess forages better adapted for these conditions as the inclusion of a fast growing cereal as rye to increase pasture production and increase the forage base in the diets with farm resources as Kikuyo grass, in order to increase the profitability of farms. Conclusions: Since there were no statistical differences in the productive performance of dairy cows, or in economic performance, the conclusion is that treatment KY is the recommended option for this season. Treatment KYCEN requires expenditures in seed and labour, so that it is not a viable option for small-scale dairy systems in this season.
Background: Intensive continuous grazing of temperate grass and legume pastures has been a feeding strategy adopted in small-scale dairy systems (SSDS) in the highlands of central Mexico that reduces ...costs and increases profitability of farms. However, temperate grasses have low persistency due to agroclimatic and management conditions, so that pastures are invaded by kikuyu grass (Cenchrus clandestinus), a sub-tropical grass that may be a valuable forage resource in these systems. There are not many studies in Mexico on kikuyu grass pastures and on the relationship between botanical composition, nutritional value and ruminal fermentation parameters, important aspects for their inclusion in feeding strategies for dairy cattle. Objective: The objective was to determine the botanical composition and to assess the in vitro digestibility of dry matter (DM), organic matter (OM), and neutral detergent fibre (NDF), and to characterize the kinetics of in vitro ruminal fermentation of a pasture based on with kikuyu grass (KY) in comparison to pastures based on festulolium cv. Spring Green (FL), tall fescue cv. TF-33 (TF), and perennial ryegrass cv. Pay Day (RG), all associated with white clover. Methodology: There were four sampling periods every 14 days. On the last day of each period, five random samples in each pasture were cut to ground level to determine botanical composition by manual separation, and 200g samples from each pasture taken by simulated grazing to determine digestibilities and the in vitro fermentation dynamics. Statistical analyses were following a split-plot model. Results: There was a higher proportion of grasses in KY and a better in vitro nutritional value for RG, related to a higher content of structural carbohydrates in KY, being a subptropical grass compared to temperate pastures with lower content of cell walls. Results: There was a higher proportion (P<0.05) of live grass in KY. There were no differences (P>0.05) among pastures for in vitro nutritional value. There were differences (P<0.05) among pastures and periods for the insoluble fraction fermentation rate (CB) and for the interaction between pastures and periods for gas production in 4.0 h of the soluble fraction (A) and the soluble carbohydrate fermentation rate (CA), but no differences between pastures, periods or the interaction (P>0.05) for other parameters of ruminal fermentation (lag time and total gas production). Implications: Pastures of kikuyu grass associated with white clover have a similar in vitro nutritional value as pastures of temperate grasses representing a valuable forage resource for SSDS. Conclusion: In spite of differences in some in vitro ruminal fermentation parameters, the in vitro nutritional value of kikuyu grass pastures associated with white clover is similar to pastures based on temperate grasses with white clover.
Background: Intensive continuous grazing of temperate grass and legume pastures has been a feeding strategy adopted in small-scale dairy systems (SSDS) in the highlands of central Mexico that reduces ...costs and increases profitability of farms. However, temperate grasses have low persistency due to agroclimatic and management conditions, so that pastures are invaded by kikuyu grass (Cenchrus clandestinus), a sub-tropical grass that may be a valuable forage resource in these systems. There are not many studies in Mexico on kikuyu grass pastures and on the relationship between botanical composition, nutritional value and ruminal fermentation parameters, important aspects for their inclusion in feeding strategies for dairy cattle. Objective: The objective was to determine the botanical composition and to assess the in vitro digestibility of dry matter (DM), organic matter (OM), and neutral detergent fibre (NDF), and to characterize the kinetics of in vitro ruminal fermentation of a pasture based on with kikuyu grass (KY) in comparison to pastures based on festulolium cv. Spring Green (FL), tall fescue cv. TF-33 (TF), and perennial ryegrass cv. Pay Day (RG), all associated with white clover. Methodology: There were four sampling periods every 14 days. On the last day of each period, five random samples in each pasture were cut to ground level to determine botanical composition by manual separation, and 200g samples from each pasture taken by simulated grazing to determine digestibilities and the in vitro fermentation dynamics. Statistical analyses were following a split-plot model. Results: There was a higher proportion of grasses in KY and a better in vitro nutritional value for RG, related to a higher content of structural carbohydrates in KY, being a subptropical grass compared to temperate pastures with lower content of cell walls. Results: There was a higher proportion (P<0.05) of live grass in KY. There were no differences (P>0.05) among pastures for in vitro nutritional value. There were differences (P<0.05) among pastures and periods for the insoluble fraction fermentation rate (CB) and for the interaction between pastures and periods for gas production in 4.0 h of the soluble fraction (A) and the soluble carbohydrate fermentation rate (CA), but no differences between pastures, periods or the interaction (P>0.05) for other parameters of ruminal fermentation (lag time and total gas production). Implications: Pastures of kikuyu grass associated with white clover have a similar in vitro nutritional value as pastures of temperate grasses representing a valuable forage resource for SSDS. Conclusion: In spite of differences in some in vitro ruminal fermentation parameters, the in vitro nutritional value of kikuyu grass pastures associated with white clover is similar to pastures based on temperate grasses with white clover.
The work herein reported closes the evaluation of the role of kikuyu grass in small-scale dairy systems in the highlands of Mexico. The objective was to compare the productive response of vacas ...lecheras en pastoreo continuo de kikuyu (
Cenchrus clandestinus
) with a sown frost-resistant tall fescue (
Lolium arundinaceum
) during the winter-spring dry season in dairy systems and determine the fatty acid profile of feeds and milk. An on-farm double cross-over experiment with three periods the 14 days each was undertaken with eight Holstein cows randomly assigned to treatments sequence. Treatments were daytime grazing for 8 h/d of a Cajun II endophyte free tall fescue pasture invaded by kikuyu grass (CJ) or a naturally invaded kikuyu grass pasture (KY), both associated with white clover (
Trifolium repens
) and annual ryegrass (
Lolium multiflorum)
. Cows were supplemented in pens with 6.0 kg DM/cow/day with maize silage and 4.6 kg DM/cow/day of commercial concentrate. The fatty acid profiles of feeds and milk were determined by gas chromatography. There were differences (
P
<0.05) for net herbage accumulation and chemical composition between pastures, but not for in vitro digestibility or estimated metabolizable energy. In animal variables, protein content in milk was higher in KY (
P
<0.05). There were significant differences (
P
<0.05) among experimental periods for milk fat content and milk urea nitrogen with the highest values in Period 3. Pasture DM intake was lowest (
P
<0.05) in Period 3. In terms of fatty acid content, there were significant interactions (
P
<0.05) for vaccenic acid (C18:1t11) and linoleic acid (C18:2c9c12) with the highest values in Period 3. Linolenic acid (C18:3c9c12c15) was higher in milk when cows grazed KY and significantly higher (
P
<0.05) in Period 3. It is concluded that kikuyu pastures complemented with maize silage and concentrates in winter-spring perform as tall fescue pastures in the season of herbage scarcity. Milk from cows grazing kikuyu grass pastures complemented with maize silage and concentrates has a higher content of linolenic fatty acid and an atherogenic index favorable for human health.
This technical note sought to examine the ability of near-infrared reflectance spectroscopy (NIRS) to predict the chemical content and organic matter digestibility (OMD) of whole plants and the ...morphological components of forage sunflower. Empirical models for the prediction of OMD values from chemical components were developed, and their predictive ability vs. NIRS models was assessed. The total set of samples (n=147) was composed of whole plants (n=14) and morphological components (n=133) from different experiments performed at Galicia (Spain) and were scanned using a Foss NIR System 6500 instrument. The reference values of OMD corresponded to in vitro determinations (n=112 samples) from laboratory incubation tests using rumen fluid. The predictive capacity of the NIRS models was assessed by the coefficient of determination value in external validation (r2 ), showing good to excellent quality prediction of OMD and chemical components with values of r2 ≥0.88. However, the estimation of lignin did not show predictive utility (r2 =0.40). Using the NIRS models to predict the OMD of whole plants and morphological components of forage sunflower led to a decrease in the standard error in external validation, in contrast to the best empirical equation through the chemical components of samples (from ±8.25 to ±3.23%). This technical note showed that NIRS is a suitable technology, providing a rapid assessment of forage sunflower. However, these results should be considered preliminary, as they are based on a limited number of samples, and it is desirable to improve the performance of NIRS equations by increasing the dataset in future works.
This study was conducted to determine the effects of increasing doses of plant extracts of moringa, thyme, and rosemary on in-vitro gas production (IVGP) of four fibrous feeds (kikuyu grass, alfalfa ...hay, oat hay, and corn stover). The extracts were applied at doses of: 0 (control), 6 (low), 12 (medium), and 18 (high) ml/g dry matter (DM). IVGP was assessed using three fistulated goats and different incubation periods. At the end of incubation, dry matter degradability (DMd), gas yield (GY24), metabolizable energy (ME), short chain fatty acids (SCFA), and microbial crude protein (MCP) production were determined. The results showed that the increasing doses of the evaluated extracts had neither linear nor quadratic effect on gas production (GP) of all fibrous feeds (P 0.05). The addition of plant extracts increased GP at all incubation periods (P 0.05), being higher for thyme. Moringa, thyme, and rosemary extracts altered ruminal fermentation parameters, including ME, MCP, SCFA, the partitioning factor at 72 h of incubation (PF72), and DMd, being higher for thyme followed by rosemary and moringa. In conclusion, the addition of thyme extract increased GP, ME, MCP, SCFA, PF72, and DMd compared with rosemary and moringa plant extracts. However, additional in-vivo studies should be conducted to confirm these effects.
Abstract This technical note sought to examine the ability of near-infrared reflectance spectroscopy (NIRS) to predict the chemical content and organic matter digestibility (OMD) of whole plants and ...the morphological components of forage sunflower. Empirical models for the prediction of OMD values from chemical components were developed, and their predictive ability vs. NIRS models was assessed. The total set of samples (n=147) was composed of whole plants (n=14) and morphological components (n=133) from different experiments performed at Galicia (Spain) and were scanned using a Foss NIR System 6500 instrument. The reference values of OMD corresponded to in vitro determinations (n=112 samples) from laboratory incubation tests using rumen fluid. The predictive capacity of the NIRS models was assessed by the coefficient of determination value in external validation (r2), showing good to excellent quality prediction of OMD and chemical components with values of r2≥0.88. However, the estimation of lignin did not show predictive utility (r2=0.40). Using the NIRS models to predict the OMD of whole plants and morphological components of forage sunflower led to a decrease in the standard error in external validation, in contrast to the best empirical equation through the chemical components of samples (from ±8.25 to ±3.23%). This technical note showed that NIRS is a suitable technology, providing a rapid assessment of forage sunflower. However, these results should be considered preliminary, as they are based on a limited number of samples, and it is desirable to improve the performance of NIRS equations by increasing the dataset in future works.
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