Octavio Alonso Castelán Ortega

Effects of crossbreeding on milk production and composition in dairy sheep under organic management

The crossbreeding of local sheep breeds with dairy breeds is an option to improve dairy production parameters in organic sheep dairy systems. Weekly milk yield (WMY) was recorded and individual samples of milk for chemical analysis were taken during 17 weeks from 45 dairy ewes of the following three genotypes: 15 East Friesian (EF), 15 EF × Suffolk (EF × SF) and 15 EF × Pelibuey (EF × PL) under organic management. For analysis of the lactation curve the Wood gamma model was used. The effect of genotype on the WMY was analysed using repeated-measures. The comparison of the least square means among genotypes for total milk yield (TMY), daily milk yield, protein content, protein yield, fat content, fat yield, non-fat solids concentration, non-fat solids yield, total solids yield and acidity was analysed using a general linear model. The genetic group influenced only in the ascent phase of the lactation curve, with values of the Parameter b of model Wood higher in EF (P = 0.01). There were no differences (P > 0.05) between genotypes in relation to the WMY, TMY, protein content and acidity; however, the effects of week of lactation trial and the interaction of genotype and week of lactation trial on WMY were significant (P < 0.05). The values of daily milk yield, fat yield, protein yield and total solids yield were higher (P < 0.005) in EF and EF × SF than EF × PL. Fat content was higher in EF × PL. EF × SF had similar values of TMY than EF and better chemical composition, which places this genotype as an option of crossbreeding in dairy sheep systems under organic management with similar agro climatic characteristics to the present study.

Nutritional value of forage species from the Central Highlands Region of Mexico at different stages of maturity

This paper has two objectives, the first is to determine the chemical composition, gas production parameters and the gas release kinetics, at different stages of maturity, of three grasses and a legume commonly found in long established pastures in Mexico central highland plateau. The second is to combine the gas release kinetics analysis and the GP fitted to a mathematical model in order to improve the biological understanding of the fermentation kinetics obtained from the GP technique. Representative samples of Pennisetum clandestinum (kikuyu grass), Sporobolus indicus (mouse tail), Eleocharis dombeyana (reed), Trifolium amabile (Aztec clover) plus a composite sample were collected in the growing season (July, September and November 2003) and analysed using an in vitro gas production (GP) technique. The accumulated GP was fitted to the model described in PALMER et al. (2005). Significant differences (P<0.001) were observed among species and periods for chemical composition, organic matter and neutral detergent fibre digestibility. Significant differences (P<0.05) were observed regarding fermentation parameters and gas release kinetic, with T. amabile and P. clandestinum being the species with the highest fermentability, whereas S. indicus and E. dombeyana were poorly fermented. P. clandestinum and T. amabile showed higher nutritive value than S. indicus and E. dombeyana. Composite samples were influenced by the chemical and fermentation characteristics of all species. It was concluded that the use of gas release kinetics analysis was useful for differentiating the fermentation kinetic of the soluble and insoluble fraction in the grasses and legume. Therefore by performing both approaches, the gas release kinetics analysis and the GP fitted to a mathematical model, gave a better description of the fermentation kinetic of grasses and the legume was achieved when only one approach had been used.

Effect of field pea (Pisum sativum L.) level on intake, digestion, ruminal fermentation and in vitro gas production in sheep fed maintenance diets

The objective of this study was the characterization of the nutritive value, ruminal fermentation and nutrient digestibility of field pea (Pisum sativum L.) hay (FPH) by-product through in situ, in vitro and in vivo tests. A FPH diet was administered ad libitum to four sheep (live weight (LW) 38.0 ± 2.0 kg) at four inclusion levels (0, 25, 50 and 75%) over a conventional sorghum grain/oat straw ration in a 4 × 4 Latin square design. The in situ degradability of FPH was 67% dry matter (DM), 71% crude protein and 66% neutral detergent fiber (NDF). The inclusion of FPH did not affect (P ≥ 0.05) the DM (61 ± 0.4 g/LW(0.75) /day) and organic matter (OM) intake (56 ± 0.7 g/LW(0.75) /day). Total DM digestibility (68 ± 2.5%), OM (70 ± 3%), and NDF (60 ± 3%), were not different (P ≥ 0.05) between control and FPH inclusion diets. The diet had no effect on ruminal pH, ruminal ammonia concentration, total and individual volatile fatty acids. The chemical composition and sheep intake behavior indicate that FPH by-product is medium quality forage when incorporated in maintenance rations.

A comparison of processed sorghum grain using different digestion techniques

ABSTRACT This study compares in situ, in vitro (DaisyII and gas production) and in vivo techniques to estimate the degradation of dry matter (DM), organic matter (OM), and N of sorghum grain. We used whole dried sorghum (WDS), dry cracked sorghum (DCS), the reconstituted whole sorghum silage (WSS) and reconstituted cracked sorghum silage (CSS). The residues obtained from the ruminal digestion in vitro (DaisyII) and in situ were analysed for their intestinal digestion (pepsin–pancreatin). OM was similar (981.32 ± 0.52) in all treatments, WSS showed the highest (P < .001) crude protein (CP) concentration compared with the other treatments, whereas CSS showed the highest amount of starch (P < .001) compared to other treatments. The apparent degraded substrate (ADS) was higher (P < .038) for whole sorghums, rumen degradable protein (RDP) was higher for WDS and WSS (P = .003), while protein digestible in the intestine (PDI) was higher for sorghums silage (P < .001) compared with dry sorghums. ADS was higher (P < .022) using the in sacco technique compared with the other methods, while for the RDP and PDI methods in sacco and in vitro (Daisy) showed the better degradation compared with in vivo. The reconstituted ensiling sorghum grains had a favourable response in the availability of nutrients, compared with dried sorghums.

COMPARACIÓN ENTRE DOS MÉTODOS DE VENTILACIÓN EN LA COMPOSICIÓN QUÍMICA DE COMPOST DE ESTIÉRCOLES PECUARIOS

Este trabajo comparo el efecto de dos metodos de ventilacion en la composicion quimica de cuatro compost de estiercoles pecuarios. Para cada tipo de estiercol mezclado se realizo un experimento de compostaje. En cada experimento (Exp) se ensayaron dos metodos de ventilacion: manual con pala (Vm) y con tubos de policloruro de vinilo perforados (Vt). El Exp 1 se denomino compost estiercol bovino (CBo + Vm, CBo + Vt), el Exp 2 compost estiercol caprino (CCa + Vm, CCa + Vt), el Exp 3 compost estiercol equino (CEq + Vm, CEq + Vt) y el Exp 4 compost estiercol ovino (COv + Vm, COv + Vt). Durante el proceso se analizaron temperatura, potencial de hidrogeno (pH), conductividad electrica (CE), materia organica (MO), carbono organico (C), nitrogeno total (N), relacion carbono/nitrogeno (C/N), fosfato (PO 4 ), potasio (K), magnesio (Mg), sulfato (SO 4 ), calcio (Ca), sodio (Na), hierro (Fe), manganeso (Mn), boro (B), zinc (Zn) y cobre (Cu). Para cada experimento se utilizo un diseno completamente aleatorizado con tres repeticiones. En las variables de composicion quimica se realizo un analisis de varianza de un factor utilizando el programa Minitab y las medias se compararon con la prueba de Tukey (p 0.05). El producto proveniente de CEq + Vt presento menor relacion C/N (p = 0.049). Los metodos de ventilacion no influyeron en las caracteristicas quimicas de los compost de estiercol bovino, caprino y ovino, sin embargo, en el compost de estiercol equino al colocar tubos en las pilas de compostaje, se favorecio la degradacion de la MO y redujo la relacion C/N. Se concluye que los dos metodos de ventilacion se recomiendan en los CBo, CCa y COv. Y el metodo de ventilacion con tubos se recomienda en el CEq.

Diferentes silagens sobre a fermentação in vitro em coelhos

The effect of chemical composition of silages on in vitro gas fermentation profiles in rabbits was examined. The study was performed using 7 silages: beans (Phaseolus vulgaris), faba bean (FB, Vicia faba), common vetch (CV, Vicia sativa), ryegrass (Lolium perenne), barley (B, Hordeum vulgare), barley with common vetch (BCV) and barley with faba bean (BFB). We used 3 New Zealand White (NZW) rabbits as donors of caecal content in each incubation run (n=3). Data were analyzed in a completely randomized experimental design. The CV silage showed higher values of crude protein (CP), followed by FB and bean silages (P<0.001). Barley silage had the lowest CP content (96g kg-1 DM) (P=0.001). The NDF and ADF content were lower (P<0.001) for beans and CV compared with the rest of the forage silages. Ryegrass silage had higher values of dry matter degradation, organic matter degradation, relative GP and SCFA (P<0.001). The highest values of digestible energy were for CV and bean silages (P<0.001). Ryegrass and CV silages showed higher levels in GP parameters, which could be associated with their better chemical composition characteristics, mainly protein and fiber content.

Organic Dairy Sheep Production Management

Organic production systems are based on natural processes, the use of local feed resour‐ ces, and the maintenance of biodiversity in all senses. Several studies have noted the posi‐ tive effects of organic sheep milk production systems on animal welfare, animal health, product quality, and environmental impact. On the other hand, it has been reported that dairy sheep organic farms show lower milk yields and increase the susceptibility to envi‐ ronmental impacts compared with conventional farms. The standards that regulate feed‐ ing management in organic systems are one of the most critical factors that influence milk production performance. Lower milk production is also associated with poor ability to adapt specialized dairy breeds to organic management, low genetic potential for milk production in native and local breeds, and elevated dependence on environmental condi‐ tions. However, the aim of organic dairy production is not to reach maximum dairy pro‐ ductivity but rather to integrate animal and crop production and to develop a symbiotic relationship between recyclable and renewable resources; furthermore, organic produc‐ tion positively affects the employment rate and quality of life in rural communities. Or‐ ganic dairy sheep production is one means of improving the balance between society’s demand for food and the ecological impact of the agro-alimentary industry.