Small-scale Dairy Systems Research Articles

Kikuyu pastures associated with tall fescue grazed in autumn in small-scale dairy systems in the highlands of Mexico

Intensive grazing increases the profitability and sustainability of small-scale dairy systems by reducing feeding costs. Kikuyu grass is a subtropical species from East Africa that has similar performance compared with temperate grasses when grazed by dairy cows in these systems during the summer rainy season but reduces growth and quality at low temperatures, when temperate species may have an advantage. The objective was to evaluate intensive grazing of kikuyu pastures (KYKY) alone or in association with two varieties of endophyte-free tall fescue, TF-33 (TF33) and Cajun II (CAJN), during the summer-autumn transition period when low temperatures set in, by lactating cows in small-scale dairy farms. Pasture variables were analysed with a split-plot design for sward height, net herbage accumulation and chemical composition, in vitro digestibility of organic matter, and estimated metabolisable energy content of herbage and concentrate. Experimental design for animal variables was a 3 × 3 Latin Square repeated three times with nine Holstein cows and 14days experimental periods. Cows received 4.65kg DM/day of a 16% CP commercial concentrate. Milk yield and composition, live weight, and body condition score were recorded. There were no significant differences (P > 0.05) for sward height and net herbage accumulation, nor for important components of chemical composition of herbages. There were no significant differences (P > 0.05) for milk yield (19kg/cow/day) and composition, although differences (P < 0.05) were detected for live weight and body condition score. The conclusion is that there is no advantage of associating tall fescue with kikuyu in summer-autumn transition period for small-scale dairy systems.

Whole-crop triticale silage for dairy cows grazing perennial ryegrass (Lolium perenne) or tall fescue (Lolium arundinaceum) pastures in small-scale dairy systems during the dry season in the highlands of Mexico.

The dry season in central Mexico is a difficult time for small-scale dairy systems to meet feed requirements for their herds as pasture growth is limited. Conserved forage options are needed to complement pastures. The objective was to assess on-farm the production of dairy cows complemented with triticale silage (X. Triticosecale Witt. (TSL)) at two levels of inclusion (5.0 and 7.5kg DM/d), grazing pastures of two grass species during the dry season: perennial ryegrass (PRG; Lolium perenne) or tall fescue (TFC; Lolium arundinaceum) (TFC) with white clover (Trifolium repens), and 4.65kg DM/d concentrate. Experimental design was a 2× 2 factorial in repeated 4 × 4 Latin squares. Chemical composition of TSL was 96g CP/kg DM, 667g NDF/kg DM, 713g in vitro enzymatic digestibility of OM (IVEDOM)/kg DM, and pH of 4.6. There were differences (P< 0.05) in net herbage accumulation (NHA) and sward height between pastures, with higher NHA in TFC than that in PRG, although the chemical composition of PRG was higher (P< 0.05) in PC, IVEDOM, and estimated ME. There were no differences (P> 0.05) in milk yield (12.3 ± 2.63kg/cow/day), milk compositions (33.1 ± 0.45g milkfat/kg, 41 33.3 ± 0.21g milk protein/kg, 47.9 ± 0.36g lactose/kg, and 10.47 ± 2.25mg MUN/dL), body condition score (2.4 ± 0.22), or live weight (490 ± 72.8kg). At a higher inclusion of TSL, there was lower intake of pasture. Inclusion of 5.0kg DM/cow/day of triticale silage better complements grazing and sustains moderate milk yields when pasture growth and intake are limited.

Productive and economic response to concentrate supplementation by grazing dairy cows at high stocking

Small-scale dairy systems contribute to ameliorate rural poverty and to local milk supply. Their sustainability is limited by high feeding costs, mainly from purchased concentrates (CC); whereas a higher reliance on quality forage may improve profitability; but high stocking rates may justify high CC use. The objective of this work was to assess the productive and economic response by grazing dairy cows to levels of CC under grazing of ryegrass–white clover pastures under high stocking rate (4 cows/ha). Six Holstein milking cows were replicated assigned 3 X 3 Latin Square arrangements. Daily milk yield and composition were recorded, and feed intake estimated from utilised metabolizable energy. Treatments were: T1= 1.0 kg T6= 3.0 kg and T6= 6.0 kg concentrate/cow/d. There were significant differences (P&lt;0.05) for milk yield, with T6 having higher yields than T1 and T3. There were no significant differences in milk protein or fat content among treatments (P&gt;0.05). Herbage intake was significantly (P&lt;0.05) lower in T6, with no differences (P&gt;0.05) between T1 and T3. There were no differences in margins over feeding costs, but feeding cost per kg of milk was 2.2 times higher in T6 compared to T1, and margin per kilo of milk was 26 % higher in T1 than T6. Although milk yields are higher with T6, T1 and T3 require less expenditures and margins are similar. Supplementation may alleviate high grazing pressure that deteriorates pastures, ensuring the long-term sustainability of small-scale dairy farming systems.

Nitrogen utilisation efficiency in small-scale dairy systems in the highlands of Central Mexico.

Nitrogen (N) plays an important role in small-scale dairy systems, both in production costs and as an indicator of environmental impact. The objective of this study was to quantify nitrogen inputs and outputs to identify areas for improvement in nitrogen utilisation efficiency (NUE). Evaluation was in 12 small-scale dairy farms with different feeding strategies. Six followed the traditional cut and carry of irrigated temperate pastures (CUT), and six have implemented grazing of pastures (GRZ), quantifying N inputs and outputs from May 2016 to April 2017. Data were analysed by ANOVA following a split-plot model with season (rainy or dry) as main plots and feeding strategy (CUT or GRZ) as split-plots, with results in kilograms N per hectare and kilograms N per cow. There were differences (P< 0.05) between seasons and strategies in N inputs from purchased N fertilisers and purchased feeds as concentrates and roughages, showing different N inputs and outputs whether in CUT or GRZ strategies. There were also significant interactions between seasons and strategies as in the sale of animals, where GRZ sell throughout the year, while CUT sell at the beginning of the dry season. N balance ranged from 33.9 to 183.0kg N/ha, and 37.8 to 111.0 as kilograms N per cow with an interaction (P< 0.05) between season and strategies. There was a larger N surplus in GRZ during the rainy season from fertiliser inputs, which reduced N utilisation efficiency (NUE). Mean NUE in kilograms N per hectare and kilograms N per cow was 19%, with the higher efficiency for GRZ in the dry season. Farms with the best NUE had lower use of fertilisers and purchased feeds.

BLACK OAT (Avena strigosa) SILAGE FOR SMALL-SCALE DAIRY SYSTEMS IN THE HIGHLANDS OF CENTRAL MEXICO

&lt;p&gt;Black oat (&lt;em&gt;Avena strigosa&lt;/em&gt; cv. Saia) silage (BOS) as an alternative forage for the dry season in small-scale dairy systems was evaluated against maize silage (MSL) at 6.0 kg DM/cow/day. Treatments were evaluated through on farm participatory livestock research: T1=100 BOS, T2=66:34 BOS:MSL, T3=34:66 BOS:MSL, and T4=100 MSL fed to milking dairy cows that also received 4.5 kg DM/cow/day of a commercial compound dairy concentrate and 2.2 kg DM/cow/day of cut-and-carry pasture. Eight Holstein cows were allotted to a replicated 4X4 Latin Square design, with 14 day experimental periods. Daily milk yields and milk composition were measured during the last four days, and live weight and body condition score recorded on the last day of each period. Feeding costs were determined by partial budget analysis. There were no differences in milk yield (15.9±0.26 kg/cow/day), or milk composition with mean values for milkfat of 38.8±0.86 g/kg, milk protein 32.2±0.38 g/kg, and lactose 46.3±0.22 g/kg. There were also no differences in milk urea nitrogen (MUN) with a mean of 11.8±0.83 mg/dl, live weight 385.6±1.67 kg, or body condition score with a mean of 2.6±0.01. Feeding costs per kg milk were 33% higher in T1 and T2 than T4, with intermediate feeding costs in T3 (T1=0.88, T2= 0.85, T3= 0.74, T4= 0.66 R$/kg). Profit margins and income/feeding costs were all positive. Black oat silage may be an alternative forage in small-scale dairy systems in the dry season when maize silage cannot be cultivated or fails due to climate concerns.&lt;/p&gt;

Oat silage for grazing dairy cows in small-scale dairy systems in the highlands of central Mexico

The objective was to evaluate the provision of oat silage (Avena sativa) to supplement grazing dairy cows on pastures of perennial ryegrass (Lolium perenne), festulolium (Lolium multiflorum × Festuca pratense) and white clover (Trifolium repens) during the dry season when pasture growth is limited. The experimental design was a 3 × 3 Latin square replicated three times, with nine milking Holstein cows (mean live weight 496.2 ± 33.6 kg and daily milk yield 14.8 ± 2.8 kg cow−1) under on-farm participatory rural research. Experimental periods were 14 d. Simulated grazing samples of pasture herbage were analysed for chemical composition, sward height recorded and net herbage accumulation determined from exclusion cages. Treatments were the inclusion of oat silage at T0 = 0 kg DM cow−1 d−1 of oat silage, T3 = 3 kg DM cow−1 d−1 of oat silage, and T6 = 6 kg DM cow−1 d−1 of oat silage, plus 5.0 kg fresh weight commercial concentrate and 9 h of continuous grazing. Animal variables were milk yield and composition, live weight and body condition score. Feeding costs were calculated. Mean milk yield was 18.9 ± 0.27 kg cow−1 d−1 with no differences in animal variables (p > 0.05), but feeding costs per kilogram milk increased 25% for T3 and 50% for T6. Oat silage supplementation is only viable under difficult grazing conditions.

Evaluation of comparative advantages in the profitability and competitiveness of the small-scale dairy system of Tulancingo Valley, Mexico.

This article combines a Policy Analysis Matrix with a sensitivity and poverty line analysis with the objective of evaluating the economic contribution of comparative advantages to the private profitability and competitiveness of small-scale dairy systems. For 1year, socioeconomic data were collected from 82 farms selected from four strata via statistical sampling. Two scenarios were established to determine the quantitative contribution of comparative advantages: (1) a simulated scenario, which accounted for the cost of purchasing the total food and the opportunity cost of the family labour force (FLF), and (2) an actual production scenario, which accounted for the cost of producing food and eliminating the payment of the FLF and included other income. The E3 and E4 producers were the most profitable and competitive in the simulated scenario and actual production scenario. Of the four scales evaluated, the E2 and E1 producers were the most efficient in taking advantage of the economic contribution provided by the comparative advantages in their own production of food and employment of the FLF, in addition to accounting for other income, a condition that increased their profitability by 171 and 144% and competitiveness by 346 and 273%, respectively. The poverty results indicated that only E3 and E4 producers were non-vulnerable in the simulated scenario and actual production scenario. The purchase of food was the comparative advantage with the greatest sensitivity to cost increases in the two scenarios analysed, which exacerbated the effect on the E1 and E2 producers.

Supplementation of dairy cows with commercial concentrate or ground maize grain under cut-and-carry or grazing of cultivated pastures in small-scale systems in the highlands of central Mexico

Small-scale dairy systems (SSDS) in Mexico represent over 78% of dairy farms and 37% of milk production. In the central highlands, many SSDS base the feeding of herds on irrigated cultivated pastures (mostly cut-and-carry), straws, and large amounts of commercial concentrates that result in high feeding costs and low economic sustainability. Intensive grazing may result in lower feeding costs when compared with cut-and-carry strategies. The high protein content of pasture may meet requirements of dairy cows with moderate milk yield (16–20 kg milk/cow.day), so that lower protein supplements, like ground maize grain, may substitute for commercial concentrates. An on-farm experiment following a participatory rural research approach was undertaken with seven farmers evaluating commercial concentrate (CC) or ground maize grain (MG) as supplement; and two pasture managements, grazing (G) or cut-and-carry (C) of irrigated ryegrass/white clover pastures to assess productive performance and feeding costs. Six farmers participated with four milking cows each and one farmer with two groups of four milking cows in a 2 by 2 factorial experiment. Daily milk yield per cow before the experiment was used as covariate. The experiment lasted 12 weeks. There is a trend in G for higher protein content in milk (P &amp;lt; 0.10). CC showed higher body condition score than MG with a significant interaction for body condition score with the highest body condition score in CCC (P &amp;lt; 0.05). Feeding costs were 15% higher per kg of milk yield and 19% per kg of energy-corrected milk under cut-and-carry but no statistical differences were detected (P &amp;gt; 0.05) in comparison with the grazing strategy. Supplementing with home-grown ground maize grain resulted in 28.5% higher margins per kg of milk produced. Implementing grazing involves less work burden for small-scale dairy farmers, and combined with home-grown grains as supplement is a viable option that may reduce feeding costs in these systems.

Intensive grazing and maize silage to enhance the sustainability of small-scale dairy systems in the highlands of Mexico.

The effects of two innovative feeding strategies-intensive grazing (GR) and maize silage (MS)-on the sustainability of small-scale dairy systems (SSDS) were assessed in the highlands of central Mexico. On a total of 24 farms, four innovations were adopted between 2011 and 2014. Five farms continued their conventional feeding strategy (CC) of cut-and-carry pasture supplemented with commercial concentrate and ground corn grain, as well as straws (maize, oat, and wheat) in the dry season of feed scarcity; six farms implemented MS in the dry season; six farms GR of pastures; and seven farms implemented both GR and MS. Assessment in 2015 showed that farms which implemented both GR and MS had a higher local diversity score (P≤0.001), higher scores for ethics and human development, and a higher score in economic independence (P≤0.05) than farms that implemented only one of the innovations. The overall sustainability score (with range 0-100) was 46 for CC, 47 for MS, 52 for GR, and 55 for GR+MS. The innovations reduced feeding costs and enhanced sustainability, particularly when GR+MS were both implemented.

Maize silage as sole forage source for dairy cows in small-scale systems in the highlands of central Mexico

Present study was undertaken to evaluate forage options for dairy cows in small-scale dairy systems under lower availability of water for irrigation, using maize silage as sole forage or grazed cultivated pasture plus maize silage. Two groups of 5 Holstein cows balanced in live-weight, parity and days in milk were formed. The productive and economic performance of treatment T1 that received a diet of maize silage (12.8 kg DM/cow/day) plus 3.5 kg/day of a high protein concentrate (71% soyabean meal and 29% ground maize grain) was compared with treatment T2 of grazed ryegrass-white clover irrigated pasture for 8 h/day, 8.1 kg DM/cow/day of maize silage and 5.0 kg of commercial concentrate with 18% CP. The experiment lasted for 11 weeks. Milk yields were 19.2 and 17.1 kg/cow/day for T1 and T2. There were no significant differences for milk fat or protein content, live-weight or body condition score. Although total feeding costs were higher in T1 (4%), the slightly higher milk yield resulted in a cost per litre 10.5% less in T1; representing 7% higher returns/feeding cost ratio. T1 is an option in future scenarios of scarce water for irrigation and for small-scale dairy farmers without access to irrigation.

Economic and financial viability of small-scale dairy systems in central Mexico: economic scenario 2010–2018

A simulation Monte Carlo model was used to assess the economic and financial viability of 130 small-scale dairy farms in central Mexico, through a Representative Small-Scale Dairy Farm. Net yields were calculated for a 9-year planning horizon by means of simulated values for the distribution of input and product prices taking 2010 as base year and considering four scenarios which were compared against the scenario of actual production. The other scenarios were (1) total hiring in of needed labour; (2) external purchase of 100% of inputs and (3) withdrawal of subsidies to production. A stochastic modelling approach was followed to determine the scenario with the highest economic and financial viability. Results show a viable economic and financial situation for the real production scenario, as well as the scenarios for total hiring of labour and of withdrawal of subsidies, but the scenario when 100% of feed inputs for the herd are bought-in was not viable.

Oat and ryegrass silage for small-scale dairy systems in the highlands of central Mexico.

This study investigated the effects of the inclusion of oat-ryegrass silage (ORGS) in combination with maize silage (MSLG) in four treatments: T1 = 100% ORGS, T2 = 67% ORGS/33% MSLG, T3 = 67% ORGS/33% MSLG, and T4 = 100% MSLG to milking cows on continuous grazing with 4.7kg DM of commercial dairy concentrate 18% CP. Daily milk yield and composition, live weight, body condition score, and chemical composition of feeds were recorded during the last 4days of the experimental periods. Feeding costs were calculated by partial budgets. Eight Holstein lactating cows were used in a replicated 4 × 4 Latin square, with 14-day periods. There were no statistical differences (P > 0.05) for milk yield (mean 15.5 ± 5.0kg/day/cow) or composition (mean milk fat 34.6 ± 4.4g/kg, protein 32.4 ± 3.1g/kg, lactose 46.9 ± 1.6g/kg), milk urea nitrogen (11.3 ± 2.1mg/dl), live weight (434 ± 38kg), or body condition score (2.4 ± 0.15). The silage cost of ORGS was 2.5 times higher than MSLG, so the feeding cost in T1 was 26% higher per kilogram of milk than for T4, with T2 and T3 as intermediates. ORGS can be a substitute to maize silage in the proportions studied, although feeding costs were higher.

Optimal management of on-farm resources in small-scale dairy systems of Central Mexico: model development and evaluation.

This study evaluates the available on-farm resources of five case studies typified as small-scale dairy systems in central Mexico. A comprehensive mixed-integer linear programming model was developed and applied to two case studies. The optimal plan suggested the following: (1) instruction and utilization of maize silage, (2) alfalfa hay making that added US$140/ha/cut to the total net income, (3) allocation of land to cultivated pastures in a ratio of 27:41(cultivated pastures/maize crop) rather than at the current 14:69, and dairy cattle should graze 12h/day, (4) to avoid grazing of communal pastures because this activity represented an opportunity cost of family labor that reduced the farm net income, and (5) that the highest farm net income was obtained when liquid milk and yogurt sales were included in the optimal plan. In the context of small-scale dairy systems of central Mexico, the optimal plan would need to be implemented gradually to enable farmers to develop required skills and to change management strategies from reliance on forage and purchased concentrate to pasture-based and conserved forage systems.

Performance of small-scale dairy farms in the highlands of central Mexico during the dry season under traditional feeding strategies.

In Mexico, small-scale dairy systems (SSDS) represent over 78% of dairy farms and contribute with 37% of national milk production; however, they face high feeding costs. The objective of this study was to assess the performance of SSDS during the dry season in terms of milk yields, milk composition and feeding costs under traditional feeding strategies, to identify areas of opportunity for improving their profitability. The information was collected from 22 SSDS every month during dry season. Feeds were classified in quality forages (QF), supplements (SU) and straws (ST). Two factors were identified: factor 1-a positive relationship among QF, SU, milk yield and ration cost and factor 2-represented straw usage. Four feeding strategies were identified: (1) low-cost feeding strategy; (2) home-grown feeding strategy; (3) high-cost feeding strategy; and (4) straw-based feeding strategy. There were differences (P < 0.001) among feeding strategies for QF, SU, ST, total dry matter offered (TDMO), ration cost (RC), external inputs, home-grown inputs and milk yield. There were no significant (P > 0.05) differences among feeding strategies for fat and protein contents in milk. It is concluded that to improve performance and profitability and enhance sustainability in SSDS, farmers should base feeding strategies on home-grown quality forages, as it was the case in group 2 which showed lower feeding cost and better milk yield. It is also recommended to increase the inclusion of quality forages like grazing pastures and maize silages during the dry season and to avoid the inclusion of straws.

Molecular characterization and antimicrobial susceptibility of Staphylococcus aureus from small-scale dairy systems in the highlands of Central México

Staphylococcus aureus is involved in human and animal infections. Because of mastitis in dairy cows, milk can be contaminated by enterotoxin-producing strains, which constitutes a food poisoning risk. Animal handlers can be asymptomatic carriers, becoming an additional source of contamination. This research aims to improve our understanding of Staphylococcus aureus in small-scale dairy systems in central Mexico. Samples were taken in 12 dairy farms and included composite milk (from the four teats) and hand swabs from each farmer. Of 149 presumptive S. aureus isolates, 102 (84 from cows; 18 from farmers) were accurately identified by molecular methods. The genetic variability of 43 randomly selected isolates was determined by RAPD-PCR, and of these, 38 were genetically distinct (≤90% similarity). Of the 38 distinct isolates, 78.9% harboured at least one enterotoxin-encoding gene (staphylococcal enterotoxin a (sea)–sed, seg, and/or sei), whereas 100% carried icaA–icaD genes and 28% carried the bap gene. The latter three genes are all involved in biofilm formation. Susceptibility to antibiotics, bacteriocins, and bacteriophages, was also assayed; 36.8% of isolates were resistant to penicillin G. Only five isolates were resistant to bacteriocins nisin A and AS-48, and phiPLA-RODI was the most effective bacteriophage, infecting all of the isolates. These results support the need to adopt management strategies to improve hygiene and milking practices in order to enhance herd health and diminish the risk of food poisoning associated with the consumption of raw milk cheese.

Evaluation of Sustainability of Smallholder Dairy Production Systems in the Highlands of Mexico During the Rainy Season

A sustainability evaluation was undertaken with 22 smallholder dairy farms in the highlands of Mexico; following the IDEA method in the agroecological, socioterritorial, and economic scales (all scales are out of 100). Sustainability was highest for the agroecological scale (59/100), intermediate for the socioterritorial scale (53/100), and lowest on the economic scale (43/100). The sustainability of a farm is the lowest score of the three scales. In most farms, the lowest was the economic scale. A cluster analysis led to the identification of five distinct groups: Cluster 1 defined two farms not related to others, cluster 2 farms (4) were those with high agroecological scores, cluster 3 farms (8) were most representative of the area, cluster 4 included two farms with low socioterritorial and economic sustainability scores, and cluster 5 was made up of the remaining six farms with the highest economic sustainability score, but limited by the agroecological and socioterritorial scales. In all farms, there is a high reliance on bought-in inputs. Therefore, given the limited resources of these systems, the better option is to limit the number of cows to those that can be fed mostly with the production of the farm, which increases the economic sustainability. The IDEA method is a useful tool for sustainability assessment of small-scale dairy systems.

Factors influencing adoption of improved grassland management by small-scale dairy farmers in central Mexico and the implications for future research on smallholder adoption in developing countries

There have been limited recent advances in understanding of what influences uptake of innovations despite the current international focus on smallholder agriculture as a means of achieving food security and rural development. This paper provides a rigorous study of factors influencing adoption by smallholders in central Mexico and builds on findings to identify a broad approach to significantly improve research on and understanding of factors influencing adoption by smallholders in developing countries. Small-scale dairy systems play an important role in providing income, employment and nutrition in the highlands of central Mexico. A wide variety of practices and technologies have been promoted by the government public services to increase milk production and economic efficiency, but there have been very low levels of uptake of most innovations, with the exception of improving grassland through introduction of grass varieties together with management practices. A detailed study was conducted with 80 farmers who are already engaged with the use of this innovation to better understand the process of adoption and identify socioeconomic and farm variables, cognitive (beliefs), and social–psychological (social norms) factors associated with farmers' use of improved grassland. The Theory of Reasoned Action (TRA) was used as a theoretical framework and Spearman Rank Order correlation was conducted to analyse the data. Most farmers (92.5%) revealed strong intention to continue to use improved grassland (which requires active management and investment of resources) for the next 12 months; whereas 7.5% of farmers were undecided and showed weak intention, which was associated with farmers whose main income was from non-farm activities as well as with farmers who had only recently started using improved grassland. Despite farmers' experience of using improved grassland (mean of 18 years) farmers' intentions to continue to adopt it was influenced almost as much by salient referents (mainly male relatives) as by their own attitudes. The hitherto unnoticed longevity of the role social referents play in adoption decisions is an important finding and has implications for further research and for the design of extension approaches. The study demonstrates the value and importance of using TRA or TPB approaches to understand social cognitive (beliefs) and social–psychological (social norms) factors in the study of adoption. However, other factors influencing adoption processes need to be included to provide fuller understanding. An approach that would enable this, and the development of more generalisable findings than from location specific case studies, and contribute to broader conceptualisation, is proposed.

Productivity in different cattle production systems in Kenya

Cattle are kept as an important source of livelihood in many Kenyan farming households whilst also having cultural and social value. A review was undertaken to estimate productivity in the three main Kenyan cattle production systems: small-scale dairy and meat; small-scale dairy; and large-scale dairy and meat. Data on production parameters were collected through a systematic literature search of electronic databases for peer reviewed and grey literature. The parameters included were reproductive rates, mortality rates and yields. Prices for livestock and livestock products were estimated from markets. The data were used to estimate net output from cattle using the Livestock Productivity Efficiency Calculator (LPEC), a deterministic steady state model which measures productivity as net output per megajoule (MJ) of metabolisable energy (ME). The estimated net outputs per livestock unit year(-1) were USD 146.6, USD 215.1 and USD 84.8 in the large-scale dairy and meat, small-scale dairy and meat and small-scale dairy systems, respectively. Milk production contributed significantly to net output in all systems and was 91.8 % of total output in small-scale dairy. Cattle sales had the highest contribution to net output in large-scale dairy and meat system (45.1 %). Sensitivity analysis indicated that output was most affected by milk yield, age and weight at maturity and parturition rate. The productivity differences between the production systems call for more detailed research on the constraints to the production systems such as diseases, and to describe the benefits that farmers and society would obtain from disease control and improved management.

Effect of silage from ryegrass intercropped with winter or common vetch for grazing dairy cows in small-scale dairy systems in Mexico

The objective was to determine the effect of including silages of annual ryegrass (Lolium multiflorum) intercropped with winter vetch (Vicia villosa) (ARG-VV) or with common vetch (Vicia sativa) (ARG-VS) compared with maize silage (MS) on milk yield and milk composition of dairy cows grazing cultivated perennial ryegrass-white clover pastures with supplemented concentrate during the dry season. Six Holstein dairy cows with a mean yield of 19.0 kg/cow/day at the beginning of the experiment were randomly assigned to a 3 × 3 repeated Latin square. Treatments were: 8 h/day intensive grazing, 3.6 kg of dry matter (DM) per cow per day of concentrate plus MS, and ARG-VV or ARG-VS ad libitum at a stocking rate of 3.0 cows/ha for three experimental periods of 3 weeks each. Milk yield (MY) and milk composition, live weight and body condition score as well as silage and concentrate intakes were recorded during the third week of each experimental period, and pasture intake was estimated indirectly from utilised metabolisable energy. Economic analysis was obtained by preparing partial budgets. There were no statistical differences (P > 0.10) in MY, milk fat or protein content nor for live weight, but there was significant difference (P < 0.10) in body condition score. There were non-statistical differences in silage DM intake (P < 0.11); however, significant differences (P < 0.10) were obtained for estimated grazed herbage intake whilst no differences for total DM intake. Slightly higher economic returns (10%) were obtained with ARG-VS over MS, and this was 7% higher than ARG-VV. It is concluded that ARG-VS could be an option for complementing grazing for small-scale dairy production systems in the dry season as it is comparable to MS in animal performance and slightly better in economic terms.

Urea treated maize straw for small-scale dairy systems in the highlands of Central Mexico

Maize straw is the main roughage for dairy herds in campesino farms in central Mexico. The objective was to evaluate feeding milking cows on maize straw treated with 40 g/kg DM of urea (A) or untreated straw (B), and 3.0 kg/d of 18% CP concentrate. Twenty-four Holsteins in late lactation from 8 farmers were sorted in two groups: sequence A-B-A or B-A-B; periods were 28 days. Mean daily milk yield for the last two weeks per period, and live-weight and body-condition score every 14 days were used for analysis. Maize straw was ad libitum. Chemical analysis and in vitro digestibility were analysed by Student's t test, animal variables by a switch-back design. 'A' had 44.3 g/kg DM more CP and 106.5 g/kg DM higher in vitro digestibility than 'B' (710 g/kg DM +/- 0.75 'A' vs. 603.5 g/kg DM +/- 1.44 'B'). Despite higher digestibility and intake, there were no differences (P > 0.05) for milk yield, live-weight or body-condition score, although there were in straw intake (P < 0.05). Cows on 'A' ate 1.7 kg/cow/day more straw DM than on 'B'. Lack of response did not offset higher feeding costs although margins were high. Lack of response is attributed to short length of periods and late lactation of cows.