The study evaluated small-scale dairy systems with continuous grazing of pastures based on three temperate grasses festulolium (FL), tall fescue (TF), and perennial ryegrass (RG), compared with subtropical kikuyu grass (KG). All pastures were associated with white clover (Trifolium repens L.). Twelve multiparous Holstein cows were assigned to a 4 × 4 Latin square replicated three times with 14-day experimental periods. Sampling and analyses of pastures, concentrates, and animal variables followed standard procedures. FL showed a significantly (p < 0.05) higher mean sward height, but there were no differences (p > 0.05) in net herbage accumulation. There were significant differences (p < 0.05) among pastures for CP, NDF, ADF, in vitro digestibility of OM (IVOMD), and estimated metabolizable energy (eME). There were no differences (p > 0.05) between treatments for milk yield and composition, live weight, or body condition score. There were significant differences (p < 0.05) in fatty acid values for pastures in C14:0, C16:1, and C18:3n3. There were significant differences between treatments (p < 0.05) in milk contents for C18:0, C18:1t11, and C18:2c9t11. Grazing FL, TF, RG, or KY pastures showed no differences in milk yields. Higher values for C18:0, C18:1t11, and C18:2c9t11 were detected in KY, RG, and TF. RG had significantly higher MUFA than FL and higher PUFA than TF. A value under 65% of SFA, a ratio of n-6/n-3 lower than 4, and an atherogenic index of 1.7 are indicators of milk with beneficial effects for human health.

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Objective. To evaluate the botanical composition of grasslands of kikuyu (Cenchrus clandestinus) compared to tall fescue (Lolium arundinaceum cv. Cajun II), each one in association with white clover (Trifolium repens cv. Ladino), in two independent experiments conducted during two seasons, autumn 2018 and winter 2019. Methodology. Two independent experiments under small-scale milk production system (SMPS) were established in the municipality of Aculco, State of Mexico, during autumn 2018 and winter 2019. The botanical composition of grasslands under intensive continuous grazing by breeding cows was evaluated. One grassland planted with tall fescue cv. Cajun II and the other invaded by kikuyu; each grassland was associated with white clover cv. Ladino. The botanical composition of both experiments was analyzed using a complete randomized experimental design. Results. The kikuyu grassland recorded significant differences (p<0.05) with a higher proportion of forage during the winter 2018. Whereas the tall fescue cv. Cajun II grassland recorded a proportion of forage (p<0.05) higher than its proportion of dead tissue during autumn 2019. Study Implications: The study of the botanical composition of mixed grasslands destined for livestock grazing allows to identify, propose and define strategies for forage production facing agroclimatic and management conditions in order to generate a better and higher forage yield. Conclusions: The proportion of kikuyu was higher than that of tall fescue cv. Cajun II during the two seasons and years evaluated. This highlights the adaptability of kikuyu grass under agroecological conditions such as the absence of rains and high temperatures, coupled with the high stocking densities of the milk production systems in the study region.

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<p><strong>Background: </strong>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 (<em>Cenchrus clandestinus</em>), 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. <strong>Objective: </strong> The objective was to determine the botanical composition and to assess the <em>in vitro </em>digestibility of dry matter (DM), organic matter (OM), and neutral detergent fibre (NDF), and to characterize the kinetics of <em>in vitro </em>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. <strong>Methodology: </strong> 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 <em>in vitro </em>fermentation dynamics. Statistical analyses were following a split-plot model. <strong>Results: </strong>There was a higher proportion of grasses in KY and a better <em>in vitro </em>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. <strong>Results: </strong>There was a higher proportion (P&lt;0.05) of live grass in KY. There were no differences (P&gt;0.05) among pastures for <em>in vitro </em>nutritional value. There were differences (P&lt;0.05) among pastures and periods for the insoluble fraction fermentation rate (C_B) 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 (C_A), but no differences between pastures, periods or the interaction (P&gt;0.05) for other parameters of ruminal fermentation (lag time and total gas production). <strong>Implications: </strong> Pastures of kikuyu grass associated with white clover have a similar <em>in vitro </em>nutritional value as pastures of temperate grasses representing a valuable forage resource for SSDS. <strong>Conclusion: </strong>In spite of differences in some <em>in vitro </em>ruminal fermentation parameters, the <em>in vitro </em>nutritional value of kikuyu grass pastures associated with white clover is similar to pastures based on temperate grasses with white clover.</p>