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This study examines the relationship between subclinical ketosis (SCK) in dairy cows and the butyric acid content of the silage used in their feeding. Twenty commercial farms were monitored over a period of 12 months. The feed at each farm and the silages used in its ration were sampled monthly for proximal analysis and for volatile fatty acid analysis. A total of 2857 urine samples were taken from 1112 cows to examine the ketonuria from about 30 days prepartum to 100 postpartum. Wide variation was recorded in the quality of silages used in the preparation of diets. Approximately 80% of the urine samples analyzed had no detectable ketone bodies, 16% returned values indicative of slight SCK, and the remainder, 4%, showed symptoms of ketosis. Most of the cases of hyperkenuria were associated with the butyric acid content of the silage used (r 2 = 0.56; P < 0.05). As the metabolizable energy content of the feed was similar, no relationship was observed between the proportion of cows with SCK and the energy content of the feed. In our study, the probability of dairy cows suffering SCK is higher when they are eating feed made from silage with a high butyric acid content (35.2 g/kg DM intake).

IntroductionIn some countries, the small land surface available on farms, and the seasonality of forage production are some of the structural factors limiting the profitability of the agricultural and livestock sector. Moreover, the increased size of herds involves the need for more quantity of food stored to meet the nutritional needs of animals during winter and drought periods.Forage quality influences the economic efficiency of the milk and meat production. Nowadays, the technology of using green food from f ields during vegetation growth has been abandoned and replaced by inside feeding using diets of similar composition throughout the year, which includes large amounts of high quality silage (Dinic et al., 2010a).The weather, season, management, grazing intensity, chemical and botanical composition of forages to be ensiled and the phenological stage, etc., are factors affecting the epiphytic microflora of forage and their ensilability characteristics (Woolford, 1984;McDonald et al., 1991). For a successful conservation of forages, it is necessary to know the content of water soluble carbohydrates (WSC) and buffer capacity (BC), because the amount of WSC is related with the potential to resist changes in pH also called BC. Haigh (1990) demonstrated that sunshine and rainfall data might be used to predict WSC of herbage cut for ensiling and subsequent silage dry matter. In addition, researches conducted by Martínez Fernández (2003), have confirmed previous results related by Muck et al. (1991) AbstractForage ensilability mainly depends on dry matter (DM), water soluble carbohydrates (WSC) and buffer capacity (BC) values at harvest time. According to these parameters, and based on a collection of 208 forages of known ensilability characteristics including short and long term meadows for grazing, italian ryegrass, maize, triticale, soybean, faba bean crops, and samples coming from cereal-legume associations, the objective of this study has been to define a quantitative ensilability index (EI) based on a relationship between DM, WSC and BC contents at harvest date, adapted to the characteristics of fodder from wet temperate areas. For this purpose, a discriminant procedure was used to define this EI based on a linear combination of DM, WSC and BC of forages at harvest time. The quantitative calculated indexes distinguish five successive ranges of ensilability: high ensilability (EI > +28), medium high ensilability (+9 < EI ≤ +28), medium ensilability (-28 < EI ≤ +9), medium low ensilability (-47 ≤ EI ≤ -28) and low ensilability (EI < -47). This quantitative index was externally evaluated and 100% of samples were successfully classified.Additional key words: buffer capacity; dry matter; silage; water soluble carbohydrates.* Corresponding author. admartinez@serida.org Received: 15-06-12. Accepted: 24-04-13Abbreviations used: BC (buffer capacity); DISCRIM (discriminant analysis); DM (dry matter); EI (ensilability index); FC (fermentability coefficient); HE (high ensilability); HEI (high ensilability index); LAB (...

Sixty-one intact meat samples from Asturcelta autochthonous swine breed were scanned in the slaughterhouse in reflectance mode. A handheld microelectromechanical system digital transform (Phazir1624, Polychromix Inc.), with a window sampling area of 0.8×1 cm and wavelengths ranging from 1,600 to 2,400 nm, was used. With the spectra database recorded were developed different chemometrical models assaying first and second derivatives as math treatment and standard normal variate (SNV) and multiplicative scatter correction for minimizing scattering effect. The greatest predictive capacity was achieved after applying SNV and first derivative for moisture, intramuscular fat (IMF) content, and pH parameters and second derivative for CIE L*, a*, b* colorimetric values, and the Warner-Bratzler force (instrumental texture). The coefficients of determination for calibration ranged from 0.63 to 0.89. The ratio between the standard error of the laboratory and the standard error of calibration ranged from 0.8 to 2.5 for all parameters (1.7 on average) with the exception of b and pH with ratios of 3.5 and 4.1, respectively. The statistical values obtained for the models developed to estimate IMF, CIE L*, a*, b*, moisture, and pH, displayed acceptable predictive capacity. For instrumental texture, the model could be able to discriminate among tender, medium, and hard meat in carcasses for characterization slaughter purposes.