No abstract

Small-scale dairy systems are important worldwide for local and national production, and an option to overcome poverty. Effects of climate change need forage options adapted to future scenarios. This research addressed the hypothesis that black-oat (Avena strigosa Schreb.), either grazing regrowth or as first-cut silage in the dry season, is a forage option for small-scale dairy farmers in the highlands of Mexico. Part I presents performance of crop and dairy cows. There were two experiments. Treatments in Experiment 1 were restricted grazing of black-oat regrowth (BKO), black-oat with red clover (Trifolium pratense L. 'Kenland') (BKC) or a multi-species pasture (MSP) of grasses and white clover (T. repens L.) Experiment 2 evaluated inclusion of 2.5 (T1), 5.0 (T2) or 7.5 (T3) kg DM cow-1 d-1 of black-oat silage. Nine Holstein cows were used in both experiments, organized in groups of three randomly allotted to treatment in multiple 3×3 Latin squares replicated three times. Cows received 4.6 kg DM d-1 concentrate. There were no differences (P > 0.05) in animal variables with mean milk yields of 10.8 and 15.2 kg cow-1 d-1 , 37.7 and 30.0 g kg-1 milkfat, 31.1 and 32.5 g kg-1 milk protein, 512.3 and 482.2 kg live weight, and 2.6 and 2.5 body condition score, for Experiment 1 and 2 respectively. Grazing black oat regrowth was equivalent to grazing temperate pastures, and the performance of cows was independent of the amount of black oat silage supplied. Black oat is a forage resource for small-scale dairy systems for grazing and silage.

Small-grain cereals may be a forage alternative for small-scale dairy systems under limiting climatic conditions given their short agronomic cycle. Cereals as dual-purpose forages (grazing and silage) have not been evaluated in Mexico. The objective was to assess the inclusion of rye (Secale cereale L.) (SCS) or triticale (×Triticosecale spp.) silage (TRS). The treatments were: T1 = 10 kg DM cow -1 d -1 SCS, T2 = 10 kg DM TRS, in both treatments with grazing access (8 h d -1 ) of a Kikuyu grass (Cenchrus clandestinus (Hochst. ex Chiov.) Morrone) pasture and supplemented with 3.6 kg DM cow -1 d -1 concentrate; in a double cross-over with six cows and three 14 d experimental periods, animal (milk yield, live weight, body condition score, and sampling for milk composition) and feed variables (net herbage accumulation, sward height and sampling for chemical composition) were recorded during the last 4 d of each period. There were no differences (P > 0.05) between treatments for milk yield (13.3 ± 2.8 kg cow -1 d -1 ), live weight (512.1 ± 85.9 kg), body condition score (2.2 ± 0.2), milk fat (35.8 ± 5.2 g kg -1 ), milk protein (27.8 ± 0.6 g kg -1 ), milk urea N (9.8 ± 2.5 mg dL -1 ) or milk pH (6.8 ± 0.07). Feeding costs were lower in SCS (P < 0.05); which may be an alternative for small-scale dairy systems. It is concluded that both rye and triticale are good alternatives as dual-purpose forage crops.

Small-scale dairy systems face reduced availability of water for irrigation of pastures and disruption in the amount or pattern of rains due to climate change, so research on alternative short-cycle rain-fed forages is needed. Grazing reduces feeding costs and small-grain cereals may be an option. The objective was to assess on-farm the performance of dairy cows grazing 6 h/d of three small-grain cereals: rye (RYE), wheat (WHT), and triticale (TRT), and supplemented 4.5 kg DM/cow/d of concentrate. Twelve Holstein cows were used in repeated 3x3 Latin Squares with 14-day experimental periods. Pasture variables were analysed with a split-plot design, and economic analysis was performed with partial budgets. Sampling of forage (sward height, net herbage accumulation, botanical and chemical composition of herbage) and animal variables (milk yield and composition, live weight, and body condition score) were at the end of each period. RYE showed a trend (P = 0.10) for higher net herbage accumulation with highly significant differences (P < 0.001) among periods. RYE had higher DM, a lower CP content (P < 0.05) and no differences for other chemical components between treatments (P > 0.05). RYE proportion in pasture was consistently higher, whilst the lowest cereal proportion was in WHT. There were no differences (P > 0.05) for any animal variable. The RYE and TRT treatments proved useful as rain-fed forage alternatives under grazing. WHT showed lower crop and economic performance. However given the higher cereal component in pastures, regrowth potential, post-grazing herbage mass, as well as better economic performance, the RYE treatment was better ranked by the participating farmer.

Small-scale dairy systems face reduced availability of water for irrigation of pastures and disruption in the amount or pattern of rains due to climate change, so research on alternative short-cycle rain-fed forages is needed. Grazing reduces feeding costs and small-grain cereals may be an option. The objective was to assess on-farm the performance of dairy cows grazing 6 h/d of three small-grain cereals: rye (RYE), wheat (WHT), and triticale (TRT), and supplemented 4.5 kg DM/cow/d of concentrate. Twelve Holstein cows were used in repeated 3x3 Latin Squares with 14-day experimental periods. Pasture variables were analysed with a split-plot design, and economic analysis was performed with partial budgets. Sampling of forage (sward height, net herbage accumulation, botanical and chemical composition of herbage) and animal variables (milk yield and composition, live weight, and body condition score) were at the end of each period. RYE showed a trend (P = 0.10) for higher net herbage accumulation with highly signi cant differences (P < 0.001) among periods. RYE had higher DM, a lower CP content (P < 0.05) and no differences for other chemical components between treatments (P > 0.05). RYE proportion in pasture was consistently higher, whilst the lowest cereal proportion was in WHT. There were no differences (P > 0.05) for any animal variable. The RYE and TRT treatments proved useful as rain-fed forage alternatives under grazing. WHT showed lower crop and economic performance. However given the higher cereal component in pastures, regrowth potential, post-grazing herbage mass, as well as better economic performance, the RYE treatment was better ranked by the participating farmer.

There is growing interest for health attributes in foods, and milk contains polyunsaturated fatty acids (PUFA) beneficial for human health, being forages a main source for dairy cows. This research addressed the hypothesis that black oat (Avena strigosa Schreb.), either grazing regrowth or as first-cut silage in the dry season, is a forage option for small-scale dairy farmers in the central highlands of Mexico. This study presents fatty acid profile of feeds and milk. In Experiment 1 cows grazed for 8 h d-1 black oat regrowth (BKO), black oat associated with red clover (BKC) or a multi-species pasture (MSP) of perennial ryegrass, festulolium, and white clover as treatments, and in Experiment 2 treatments were 2.5 (T1), 5.0 (T2) or 7.5 (T3) kg DM cow-1 d-1 of black oat silage (BOS) as complement to grazing. Nine Holstein cows were used in both experiments, in groups of three randomly allotted to treatment sequence in a 3×3 Latin square design replicated three times. Cows also received 4.6 kg DM d-1 commercial concentrate. In Experiment 1 there were significant differences (P < 0.05) in content of saturated fatty acids (SFA) for BKO (62.4 g 100 g-1) 2.8% lower than MSP (64.8 g 100 g-1), monounsaturated fatty acids (MUFA) in MSP (31.4 g 100 g-1) were 6.5% lower than BKO (33.6 g 100 g-1), and PUFA in BKO (4.0 g 100 g-1) were 5% higher to BKC and MSP (both with 3.8 g 100 g-1). In Experiment 2 there were nonsignificant differences (P > 0.05) between treatments in fatty acid groups. Grazing black oat regrowth resulted in milk with higher PUFA contents compared to multispecies pasture representing more benefit for health; but no effect with ensiled black oat.

O Background: The implementation of polyphytic pastures composed of grasses and legumes is an important component of agricultural systems in temperate zones, since grazing pastures which can reduce feed costs— are a viable option for small-scale dairy systems (SSDS). Objective: To evaluate the continuous grazing of dairy cows in Festulolium pastures associated with annual and perennial ryegrass and with clover in two farmrs. Methodology: Two experiments were carried out. The first experiment was established in the municipality of Almoloya of Juárez using eight cows that were divided into two groups of four; the cows grazed on two pastures with Festulolium associated with annual ryegrass and they were fed with 3.6 kg DM/cow/day of commercial concentrate, for 16 weeks. The second experiment was carried out in the Northwest of State of Mexico; six multiparous cows grazed on two pastures, under a cross over design arrangement; one pasture features Festulolium cv Spring Green and the other, annual ryegrass. Milk and body condition ere measured every 3 and 12 d, respectively. Variables from both experiments were analyzed using a split-plot experimental design. Results: Neither experiment recorded significant differences for the net accumulation of forage, the height of the pastures, and their chemical composition (P>0.05). No significant differences between treatments (P>0.05) were recorded regarding the yields and chemical composition of the milk. Study Limitations/Implications: The study of mixed pastures can be an alternative for feeding grazing cows, helping to reduce costs in SSDS. Findings/Conclusions: Festulolium/annual ryegrass pastures with white clover are a viable forage alternative for small-scale dairy systems.