Clinical pathological data and analyses of mineral elements of cattle affected by epizootic botulism in the State of São Paulo

In order to study laboratorial aspects of beef cow mortality, a syndrome popularly known as ''doenca da vaca caida'', examens were made of blood, cerebrospinal fluid, serum, bone and liver samples from 32 naturally affected 4 to 9 year old cows, 27 belonging to the Nellore breed and 5 were crossbred Nellore, all originating from farms located in municipalities near Botucatu, State of São Paulo. Laboratory determinations were analysed by descriptive statistics and included hematological values, total plasma protein, plasma fibrinogen, cerebrospinal fluid analysis, and concentration measurements of serum calcium, phosphorus, magnesium, sodium, potassium, chloride, total protein, albumin, globulin, alkaline phosphatase, aspartate aminotransferase, gama-glutamyltransferase and creatine kinase activities, included bone ash percentage and concentrations of calcium, phosphorus and magnesium, and also hepatic levels of copper, zinc, iron, manganese and cobalt. In addition, mouse bioassays and complement micro-fixation tests were performed to detect botulinum toxins in liver samples. The results indicated leukocytosis (13,3+/-3,9 x10(3)/mm(3)) with neutrophilia (8,9+/-3,2 x10(3)/mm(3)), hypocalcemia (7,8+/-1,7mg/dl), hypophosphatemia (3,6+/-1,6mg/dl), hypoalbuminemia (2,9+/-0,9g/dl), increased creatine kinase activity (691,0+/-829,7 UI/1), and reduced ash percentage (60,3+/-1,9%) and low phosphorus (17,2+/-0,4%) in bone. The other values were ail within normal limits. The diagnosis of botulism, involving type C and D toxins, was confirmed as the cause of the mortality in the region of study, what is strongly consistent with the other laboratorial findings.

Voluntary intake of Tanzania grass (Panicum maximum) under rotational grazing by lactating cows

The study was conducted at Nucleo de Pesquisas Zootecnicas Nordeste of the Instituto de Zootecnia, Ribeirao Preto, SP, in a rotational grazing area of Tanzania grass (Panicum maximum), to estimate the dry matter intake by lactanting cows. The estimation of dry matter intake was calculated from the feces production estimated using extrusa Chromium-mordent and the in vitro digestibility of diet. The three treatments were crossbreed cows fed 3 kg.day(-1) of concentrate, crossbred cows without concentrate suplementation and pure Gir cows also without concentrate supplementation. The milk production was 11.98, 6.53 and 5.46 kg per cow per day, the grass intake was 8.26 +/- 5.66, 11.01 +/- 5.37 and 9.55 +/- 2.31 kg of dry matter per day or 2.15%, 2.37% and 2.34% of live weight for the three experimental groups respectively. The milk production was higher (P<0.01) for cows fed with concentrate. No difference was found for dry matter intake.

Respiratory heat loss of Holstein cows in a tropical environment

In order to develop statistical models to predict respiratory heat loss in dairy cattle using simple physiological and environmental measurements, 15 Holstein cows were observed under field conditions in a tropical environment, in which the air temperature reached up to 40 &DEG; C. The measurements of latent and sensible heat loss from the respiratory tract of the animals were made by using a respiratory mask. The results showed that under air temperatures between 10 and 35 &DEG; C sensible heat loss by convection decreased from 8.24 to 1.09 W m(-2), while the latent heat loss by evaporation increased from 1.03 to 56.51 W m(-2). The evaporation increased together with the air temperature in almost a linear fashion until 20 &DEG; C, but it became increasingly high as the air temperature rose above 25 &DEG; C. Convection was a mechanism of minor importance for respiratory heat transfer. In contrast, respiratory evaporation was an effective means of thermoregulation for Holsteins in a hot environment. Mathematical models were developed to predict both the sensible and latent heat loss from the respiratory tract in Holstein cows under field conditions, based on measurements of the ambient temperature, and other models were developed to predict respiration rate, tidal volume, mass flow rate and expired air temperature as functions of the ambient temperature and other variables.

Heritability Estimate and Genetic Correlations of Reproductive Features in Nellore Bulls, Offspring of Super Precocious, Precocious and Normal Cows Under Extensive Farming Conditions

The present work aimed to estimate heritability and genetic correlations of reproductive features of Nellore bulls, offspring of mothers classified as superprecocious (M1), precocious (M2) and normal (M3). Twenty one thousand hundred and eighty-six animals with average age of 21.29 months were used, evaluated through the breeding soundness evaluation from 1999 to 2008. The breeding soundness features included physical semen evaluation (progressive sperm motility and sperm vigour), semen morphology (major, minor and total sperm defects), scrotal circumference (SC), testicular volume (TV) and SC at 18 months of age (SC18). The components of variance, heritability and genetic correlations for and between the features were estimated simultaneously by restricted maximum likelihood, with the use of the vce software system vs 6. The heritability estimates were high for SC18, SC and TV (0.43, 0.63 and 0.54; 0.45, 0.45 and 0.44; 0.42, 0.45 and 0.41, respectively for the categories of mothers M1, M2 and M3) and low for physical and morphological semen aspects. The genetic correlations between SC18 and SC were high, as well as between these variables with TV. High and positive genetic correlations were recorded among SC18, SC and TV with the physical aspects of the semen, although no favourable association was verified with the morphological aspects, for the three categories of mothers. It can be concluded that the mothers sexual precocity did not affect the heritability of their offspring reproduction features.