Genetic Analysis Method for Staphylococcus chromogenes Associated with Goat Mastitis.

Mastitis in goats is mainly caused by coagulase-negative Staphylococcus (CNS). The identification methods for this group are based on evaluating the expression of phenotypic characteristics such as the ability to metabolize various substrates; however, this is disadvantageous as these methods are dependent on gene expression. In recent years, genotyping methods such as the Multiple Locus Variable-Number Tandem Repeat Analysis (MLVA) and gene identification have been useful for epidemiological study of several bacterial species. To develop a genotyping method, the genome sequence of Staphylococcus chromogenes MU970 was analysed. The analysis showed nine virulence genes described in Staphylococcus aureus. The MLVA was developed using four loci identified in the genome of S. chromogenes MU970. This genotyping method was examined in 23 strains of CNS isolated from goat mastitis. The rate of discrimination for MLVA was 0.8893, and the highest rates of discrimination per the index of Simpson and Hunter-Gaston were 0.926 and 0.968 for the locus 346_06, respectively. The virulence genes were present in all strains of S. chromogenes but not in other CNS. The genotyping method presented in this paper is a viable and easy method for typifying CNS isolates from mastitis cases in different regions and is an ideal mean of tracking this disease.

Milk production in dairy goats supplemented with different levels of ruminally protected methionine.

The objective of the study reported in this Research Communication was to evaluate graded levels of ruminally protected methionine (RPM) in dairy goat rations on milk production and live weight changes during 155 d of lactation. Twenty-five primiparous dairy goats (crosses of Toggenburg, French Alpine and Saanen; 45·4 ± 1·0 kg BW) were fed a basal diet (10·10% CP, 6·13 DP and 2·34 Mcal/kg ME) of corn silage, oat hay, alfalfa hay and concentrate (80% forage, 20% concentrate). After kidding, the treatments, which consisted of four oral doses of ruminally protected methionine (RPM) at 0, 1, 2 and 3 g/d, were randomly assigned to the goats. The experiment was conducted for 110 d with measurements of milk production and composition, body weight and dry matter intake. No treatment effects were detected in milk production and composition. However, goats with RPM showed a positive live weight changes during lactation which were improved as dose was increased (linear P < 0·01) whereas goats without RPM showed weight loss during the experiment.

Conducta estral, concentraciones de LH y función lútea en cabras en anestro estacional inducidas a ciclar mediante el contacto con cabras en estro / Estrous behaviour, LH concentracions and luteal function in seasonally anestrous goats exposed to herdmates in estrous

El presente trabajo tuvo como objetivo determinar el efecto de las cabras en estro sobre la actividad ovárica de sus compañeras en anestro estacional. Se utilizaron un total de 30 cabras anéstricas divididas aleatoriamente en tres grupos. El grupo I estuvo formado por 10 cabras inducidas al estro con acetato de melengestrol (MGA) combinado con una inyección intramuscular de gonadotropina sérica de yegua gestante (PMSG); el grupo II estuvo formado por 10 cabras no tratadas y mantenidas en contacto directo con los animales del grupo I durante todo el experimento, y el grupo III, formado por 10 cabras sin tratamiento que se mantuvieron alejadas de los otros dos grupos: En todos los animales se detectaron calores diariamente y se obtuvieron muestras de sangre dos veces por semana con el propósito de determinar las concentraciones de progesterona y establecer la precencia o ausencia de ovulación. Ademas se tomaron muestras de sangre para la determinación de LH cada 2 h desde las 36 hasta las 72 h posteriores a la aplicación de PMSG. Se consideró que un animal tenía actividad ovárica cuando sus valores de progesterona alcanzaron 1 ng/ml. En el grupo I, el 100 por ciento de los animales respondieron con ovulación al tratamiento. En el grupo II el 80 por ciento de los animales ovularon en un periodo de 13 días, y en el grupo III, que actuó como testigo, 40 por ciento de los animales ovularon. Los picos preovulatorios de LH se observaron a las 54.5 9 y 64 6 h para los grupos I y II, respectivamente; no se obvervaron picos de LH en el grupo III. Las diferencias observadas entre los grupos I y II con respecto al grupo III para el porcentaje de presentación de ovulución e inducción de estros fueron significativas (P< 0.05). Se concluye que la presencia de cabras en esto es capaz de inducir el estro, picos preovulatorios de LH y ovulación sincronisada en una proporción considrable de cabras en anestro estacional, lo que indica una inducción real de actividad ovárica y no simplemente una conducta de imitación