In vitro nutritional quality and antioxidant activity of three weed species as feed additives for sheep in the Central Highlands of Mexico.

Sheep production is traditional for rural communities in Mexico, based on natural grasslands and semi-stabled feeding. Quality forages are necessary to improve productivity in these systems. Weeds are an alternative to feed ruminants and to manage crops. Also, many plants have secondary metabolites beneficial for livestock. The objective was to assess the nutritive value in vitro and the antioxidant activity of three weeds (Tithonia tubiformis, Cosmos bipinnatus, and Tagetes lucida) and four treatments (T0 = control diet, T1 = diet + 5% T. tubiformis, T2 = diet + 5% C. bipinnatus, and T3 = diet + 5% T. lucida). Nutritive value was determined from chemical composition by standard methods and mineral contents by inductively coupled plasma analyses. Secondary compounds, total phenols (TP), total tannins (TT), condensed tannins (CT), and phenolic compounds, were determined by high-performance liquid chromatography, and total antioxidant activity was determined by measuring the oxygen radical absorbance capacity. Rumen fermentation kinetics and in vitro digestibility of dry matter (IVDMD), organic matter (IVOMD), and neutral detergent fibre (IVNDFD) were determined per species and treatment by in vitro gas production. T. tubiformis had the highest CP and TP contents (P < 0.05), and C. bipinnatus had the highest fibre and CT contents (P < 0.05). Inclusion of T. lucida in the diet resulted in an 18% increase in TP content and a 30% increase in antioxidant activity in comparison to the control diet. No significant differences (P > 0.05) were found in rumen kinetics parameters, IVDMD, IVOMD, IVNDFD, or metabolizable energy, indicating that the tested weeds can be used as additives to increase antioxidant activity in sheep diets without negative effects.

Relationship between calving interval and profitability of Brown Swiss cows in a subtropical region of Mexico.

Brown Swiss cattle have replaced Zebus in some dual-purpose farms in tropical and subtropical regions of Mexico, under extensive grazing management. There is limited information about the productive and reproductive performance of this breed under tropical conditions; the lack of records from small farms may be the main reason. The objectives of the study were to evaluate the relationship between calving interval (CI) and milk and beef (weaned male calves) profit in Brown Swiss cows from a dual-purpose farm under extensive management in a subtropical region of Mexico. Data from 156 cows calving from 2000 to 2014 were analysed with both a linear and a survival model. Mean CI was 438 ± 49 days, mean age at first calving was 40 ± 6 months and length of productive life was 7 ± 3 years. The effects of parity, calving year and calving season were significantly related to CI (P < 0.05), whereas the effect of calf sex was not. Cows calving in the autumn and winter had shorter calving intervals, probably because supplements received during the dry season months improved energy balance. The highest culling rate was 28% at 45 months of age. Milk yield and total profit increased as CI increased from 12 to 20 months; beef contribution to total profit decreased as CI and milk yield increased. Calving intervals of more than 12 and up to 20 months had a positive effect on the milk production and profitability of dual-purpose cows in a subtropical region of Mexico.

Multi-species pastures for grazing dairy cows in small-scale dairy systems in the highlands of Mexico.

Grazing in small-scale dairy systems reduces costs and enhances sustainability. However, binary pastures (BP) have low persistency, which may be increased by including more species given their flexibility to withstand different agroecological and management situations. The objective was to assess a multi-species (MS) pasture of perennial ryegrass (RG), tall fescue (TF), bromegrass (BG), red clover (RC) and white clover (WC) in comparison to a BP of perennial ryegrass (RG) - WC grazed by six Holstein dairy cows during the dry season in an on-farm double cross-over experiment, with three 14-day each experimental periods for animal variables, and a split-plot design for pasture variables at 3 cow/ha. There were differences (P < 0.05) between pastures for sward height (MS 5.0 vs. BP 4.0 ± 0.10 cm, both MS and BP) and net herbage accumulation (MS 902 vs BP 228 ± 172.4 kg DM/ha, both MS and BP) and differences (P < 0.05) for chemical composition among periods. There were differences (P < 0.01) among periods for estimated DM intake, but no differences (P > 0.05) for milk yield (mean 16.8 kg/cow/day), milk fat or protein content (mean 31.8 and 28.8 g/kg). Multi-species pastures are a viable alternative for SSDS in the highlands of central Mexico, being more resistant to harsh environment and to weed and kikuyu grass invasion.

Effect of total mixed ration composition and daily grazing pattern on milk production, composition and fatty acids profile of dairy cows.

The possibilities of using high quality pastures in conjunction with total mixed ration (TMR) during the grazing season have been examined. An experiment with sixteen Holstein cows blocked and randomly assigned to four treatments in a factorial arrangement was conducted in order to evaluate the influence of grazing time of day (day or night) and type of silage (maize or Italian ryegrass) included in the TMR of dairy cows grazing 12 h daily on milk yield, composition and fatty acid profile. The silage type had no effect on the dry matter intake, milk yield and fat and protein proportions. However, cows grazing during the night ate more grass than cows grazing during the day (8·53 vs. 5·65 kg DM/d; P<0·05). No differences were seen between grazing-time with respect to milk production, fat and protein contents. However, the proportion of polyunsaturated fatty acid was higher in milk of dairy cows grazing at night-time than grazing at day-time, especially 18:2n-6 (2·37 vs. 2·12 g/100 g FA respectively, P<0·05) and 18:2cis9trans11 (2·08 vs. 1·74 g/100 g FA respectively, P<0·05).

Local feeding strategies and milk composition in small-scale dairy production systems during the rainy season in the highlands of Mexico.

The objective of the work was to identify local feeding strategies in small-scale dairy production systems during the rainy season in the highlands of Mexico, and to determine their effects on milk yields (MY), milk composition and economic viability. Twenty-two dairy farms were monitored by monthly visits, recording and sampling milk from between two and six cows in each farm, live-weight was also recorded. Samples from feeds used in that month were taken and feeds given to the dairy herd were weighed. Economic data was also recorded. Milk composition and milk urea nitrogen were determined, as well as chemical composition of feeds. Eighteen feedstuffs were identified, grouped in: HNH feeds-high in neutral detergent fibre (NDF) and in DM matter; HNL feeds-high in NDF but low in DM; HCh feeds-high in non-fibrous carbohydrates; and HCP feeds-high in crude protein. Four feeding strategies were identified: strategy 1 uses HND, HNL and HCP; strategy 2-HND, HNL, HCh and HCP; strategy 3 HNH and HCP; and strategy 4 HNL and HCP. Of participating farms, 73.4% followed strategy 1, 11.3% strategy 2, 11.3% strategy 4 and 3.8% strategy 3. There were no statistical differences (P > 0.05) between strategies for MY and milk composition, but there were differences (P < 0.05) for ration costs. Multiple regression analysis showed no significative (P > 0.05) model relating intake of feed groups and milk fat content, but milk protein and SNF contents were significantly explained by intake of HCP. When expressed as MY and milk components yield, milk fat yield was significantly explained by intake of all four feed groups, but milk protein and SNF yields were explained only by intake of HCP and LW. MUN excretion was explained also by HCP intake. All feeding strategies produced positive economic returns, on average generating the equivalent of 3.45 minimum wages of the area.

The role of working equines to livelihoods in current day campesino hill-slope communities in central Mexico.

Small-holder campesino agriculture is based on the diversified use of resources and off-farm work. Working equines have a multifunctional character and sustain the diversification of livelihoods having different values as assets or providing services. The objective was to identify the role of working equines in current diversification strategies in the livelihoods of campesino families in a hill-slope community in central Mexico within livelihoods analysis. Thirty-one variables related to ownership and use of working equines were analysed by cluster analysis and descriptive statistics contrasting the presence of equines in the diversification of livelihoods. Four groups were identified, determined mainly by age of farmer and number of family members who utilise equines. Results show these systems diversify in response to conditions of risk or to take advantage of opportunities, such that a balance is reached by resorting to off-farm activities without the total loss of components of the farming system. Two main situations were found in relation to working equines: the disappearance and change of functions of the large equines (mules), and the adaptation of small equines (donkeys) to the new conditions. It is concluded that there is a process of adaptation in hill-slope campesino farms such that large equines are less present in farms that have moved towards more diversification, but are kept in those farms less diversified. The use of equines for draught force in agricultural production and as pack animals continues, as is the presence of small livestock (sheep and poultry) irrespective of the context of the farm.

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.