Vergleich zweier Methoden der Altersbeurteilung an Zähnen altersbekannter wildlebender Fleischfresser 1

Two age-determining methods were conducted on representatives of known age from the Order Carnivora (4 red foxes, 3 tree martens, 3 stone martens, 2 racoons, 2 badgers, 1 polecat and one otter). Age determination employed with the aid of tooth wear nearly agrees with the real age of the animals. Dating based on the formation of the age-dependent cement zone coincided well with the known ages of the individual specimens. However, in real foxes the figure one must be added to the number of cementum layers counted determining the definitive age of individuals. For representation of the cementum layers transverse sections of the apical part of the tooth root of canini, P₂ and P₃, stained with methylene blue, should be used. It is important to note that the dentino-cemental line should not be considered when counting the year rings in the cement.     

Age Determination in the Bush Squirrel,Paraxerus Cepapi Cepapi

Tooth eruption and wear, measurements of skulls, eye-lens mass determination and different aspects of phallic morphology were used in an attempt at age classification in the bush squirrel, Paraxerus c. cepapi. The first method proved the most practical and allowed for three immature and three adult age classes. Three knownage immature animals which fitted into the three immature tooth-wear classes, together with comparison of mass of known-age field young with that of collected young, enabled an estimate to be made of ages of the different immature classes. Beyond sexual maturity age could not be ascribed to animals.     

Estimation of mature live weight using some body measurements in Karya sheep

The aim of this study was to determine models which will be used for the estimation of adult live weights based on some body measurements using multiple regression model in Karya sheep of different age groups. Animal material of the study consisted of a total of 215 Karya sheep. Least squares means for live weight, body length, rump height, withers height, back height, chest depth, chest girth, and chest width of Karya sheep in Adnan Menderes University Group Sheep Breeding Program elite flock and breeder flocks were found as 47.24 kg, 67.08, 68.29, 68.58, 66.97, 30.04, 93.24, and 18.29 cm, respectively. Karya ewes were put into five categories according to ages (2–6 years). High positive phenotypic correlation coefficients were observed between live weight and body measurements of animals in different age groups (2–6 years). Among the formed multiple regression models, the highest coefficients of determination (R ²) were obtained from the models formed for body length or body length and chest girth together (R ²?=?0.79, R ²?=?0.87). It is concluded that live weight of Karya sheep can be estimated with a high accuracy using some body measurements and statistical methods.     

Body growth of captive eland Taurotragus oryx in Natal

Post-natal growth in live mass and in body dimensions with age is described in a captive herd of eland Taurotragus oryx, using the von Bertalanffy growth equations. Asymptotic live mass of males (575 kg) was 45% higher than the value for females (316 kg). Asymptotic body dimensions were also higher in males, girth by 27%, height at withers by 13% and body length by 9%, these data illustrating the sexually dimorphic nature of growth in eland. In winter, body growth rates were significantly lower than in the summer, but these variations are not apparent from theoretical von Bertalanffy growth curves. A combination of linear measurements is described for the prediction of live mass.     

Genetic analysis of production traits in turbot (Scophthalmus maximus) using random regression models based on molecular relatedness

Reliable estimates of genetic parameters for growth traits as a trajectory of age are needed to optimize existing turbot breeding programmes. To evaluate the potential of early selection strategies, the use of biometric body measurements, length (L), width (W) and area (A), at early ages as alternative indicators for the selection trait at harvest was explored. Random regression model (RRM) based on molecular relatedness (MR) was used to analyse the trajectory of genetic parameters for growth traits in turbot from 162 to 756 days posthatch (dph). Heritability estimates for body weight (BW) ranged from 0.34 to 0.54. Heritability estimates for W, A and L were also moderate to high ranging from 0.18 to 0.43. Estimates for L and W declined with age, while those for A increased towards harvest age. Genetic (r_G) and phenotypic (r_P) correlations between BW and the three morphometric traits L, A and W were estimated using simple bivariate animal models at young (AC1), medium (AC2) and old (AC3) age classes. Correlations between BW and morphometric body traits were high, ranging from 0.7 to 0.9 in all three age groups. Genetic correlations between traits were highest (>0.9) in AC3. To explore the potential for early selection, genetic correlations were derived from the RRM between all days of measurement for all traits separately. From dph 300 onwards, intratrait estimates of r_G were moderate to high (above 0.7 for dph 410 and higher ages for traits BW, L and A). Results showed that genetic selection for BW, L and A is promising and that A and L could be successfully used as alternative indicator traits if measurements of BW are not available. Large BW and A at harvest could be achieved as a correlated response to early selection for these traits at around 500 dph.     

Contributions to the Biology of the Panga Pterogymnus Laniarus (Pisces : Sparidae): Age,Growth and Reproduction

All the fish used in this investigation were caught by commercial side trawlers along the eastern Cape coast of South Africa. Age and growth of P. laniarius was determined from otoliths collected monthly from April 1974 to September 1975. The validity of annuli was proved by monthly edge examination of the otoliths. There is no difference in growth between the sexes. The Von Bertalanffy equation L_t = 48,1 (l-e^{-0,10(e + 0.22)}) was found to describe the growth of the panga in length. Some fish become sexually mature at a total length of 26 cm. Fifty percent maturity is attained at a length of 28 cm, between the ages of 4 and 5 years. All fish are sexually mature at a total length of 32 cm, at an age of 6 years. The spawning season of the panga extends from mid-September to May.     

Age Determination of the Blue Wildebeest Connochaetes Taurinus in Zululand

Age determination methods for the blue wildebeest employed the use of tooth eruption sequence, cementum layers from macroscopic tooth sections, eye lens mass, and tooth attrition. Eleven eruption classes were arrived at, providing a reliable method of age determination up to 3,5 years. The times of eruption of specific teeth were compared with data from East Africa. The restricted birth interval of wildebeest enabled some sub-adult animals to be regarded as ‘known-age’ which were used to arrive at a value for the number of cementum layers laid down per annum, and to provide a ‘correction factor’ for the period before eruption and cemental deposition. The nature of tooth cementum lines in wildebeest is discussed, and changes in infundibular patterns were related to cementum or eruption age, providing an age-wear chart with 14 adult classes, adequate for life-table data. Incisiform wear in wildebeest appears to follow a curvilinear relationship. When eye lens mass was plotted against cementum or eruption age, the resultant curve served only to distinguish between animals below one year old and the older age classes. Anomalies in dentition are discussed. Some criteria for age determination in the field are presented.     

Estimation of body weight in Indian elephants (Elephas maximus indicus)

Thirty-nine adult Indian elephants (Elephas maximus indicus) of both sexes and various ages and weights, belonging to the Forest Department of the Government of Kerala (India), Temple Devaswoms, Gemini Circus and other private agencies, were used to derive formulae to predict body weight and height from body measurements. Several models were fitted separately for males and females and also for adults irrespective of sex. The best prediction of body weight (W) in kg was obtained for adults irrespective of sex by using two parameters, the body length (L) in cm from the base of the forehead to the base of the tail, and the chest girth (G) in the formula W=–1010+0.036 (L×G). No single parameter gave as accurate a prediction of the body weight, and the inclusion of height as a third parameter did not improve the prediction. No significant improvement in the accuracy of prediction resulted from the use of different formulae for males and females. An equation to predict the height at the shoulders (H) in cm from the right forefoot circumference (C) in cm in adult elephants irrespective of sex was also derived. This was H=–1.60+1.99 C.     

The estimation of live weight based on linear traits in indigenous Tswana goats at various ages in Botswana

The objective of this study was to determine the usefulness of some linear body measurements in predicting live weight in indigenous Tswana goats at various ages. Data for this study were obtained from 2,783 goats sampled from six agricultural regions of Botswana except for Tsabong and Ghanzi districts. Fifteen farmers keeping goats were randomly selected from each district and records taken on a random sample of 4–12 animals per farm depending on the 1999 Botswana Government average district flock size. Body measurements recorded were heart girth, height at withers, body length, shoulder width, and live weight. Information on age of each animal was estimated from dentition; flock size and sex of the animal were also recorded for each farm. Regression analysis using stepwise selection method in Statistical Analysis System was used to determine prediction equations for live weight with heart girth, height at withers, body length, and shoulder width as independent variables for male and female goats of different ages. In all models, heart girth contributed most in explaining variation in body weight as shown by high partial R ² which ranged from 0.48 for female mature to 0.80 for mature male goats. Using mean square error, R ², and Mallows’ C(p), the best prediction equations were for female and male kids (R ² = 0.83 and 0.82, respectively) and mature male goats (R ² = 0.82). The poorest model was for mature female goats with R ² = 0.57. Live body weight could be estimated with accuracy from linear body measurements in Tswana goats which are unique for each sex and age. More research is required to explore using these models to develop measuring tapes for use by resource poor farmers who keep indigenous Tswana goats.     

Mandibular cheek tooth eruption and development in Hereford cross Friesian steers as a means of age determination

Summary

The development of the mandibular cheek teeth was examined, both visually and by radiograph, in a group of 76 Hereford cross Friesian steers, of which all but one were slaughtered at the same weight ‐ 464 kg (1020 lb).

The age of the youngest animal was 1 year 0.3 months whereas the slaughter ages of the others ranged from I year 3 months to I year 8 months. The first molar was fully erupted and crown and root formation complete in all but the youngest steer. In the other five cheek teeth there were one or more siginificant differences between the mean ages of tooth development stages as assessed by radiograph. Cattle of 1 year 3 months could not be absolutely distinguished from those of 1 year 8 months by intra‐oral second molar eruption. Examination of stages of development seen radiographically gave a maximum age range of 4 months before differentiation. In this study, development bf the first two molars was in advance of the three permanent premolars and in these latter teeth the second premolar was the most developed.     

Fetal development of the bat Miniopterus schreibersi natalensis

Prenatal development in the fetus of Miniopterus schreibersi natalensis is discussed. Due to the long period of delayed implantation in this subspecies, the age of even the smallest fetuses, where the fore-limb buds just become visible will be around 150 days. The most reliable criterion for age determination proved to be body mass, and all fetal ages were estimated by using the equation t = W^1/3/0,0145 + 144.     

Suitability and calibration of a rebound tonometer to measure IOP in rabbit and pig eyes

Objective To utilize the Icare tonometer TAO1 for intraocular pressure (IOP) determination in experimental animals. To calculate true IOP calibration functions for rabbit and porcine eyes. Animals Enucleated eyes of 3‐year‐old healthy experimental rabbits (New Zealand white), and healthy 1 year old experimental pigs (Deutsche Landrasse) were used for the determination of IOP. Procedures Manometric (Geuder GmbH, Heidelberg/Germany) and rebound tonometry (Icare tonometer TAO1, Icare, Helsinki/Finland) were used to record IOP in enucleated animal eyes (rabbit n = 2, pig n = 3). Results The Icare tonometer TAO1 measurements underestimated true IOP by 37–60% in rabbit eyes and 17–63% in porcine eyes. IOP values obtained by both rebound and manometric tonometry for rabbit and porcine eyes followed a linear regression curve. Linear functions were calculated to correct the Icare tonometer TAO1 measurements to true IOP for both rabbit (p = 1.4244p_ic + 4.2421) and porcine eyes (p = 1.0799p_ic + 5.8557). Conclusions The Icare tonometer TAO1 can be utilized for IOP determination in rabbit and porcine eyes when measured values are corrected with the appropriate linear function.     

Repeatability, reproducibility, and effect of head position on central venous pressure measurement in standing adult horses

Background: Central venous pressure (CVP) is a used as an estimation of intravascular volume status in various species. Techniques for measuring CVP in horses have been described, but the repeatability of these readings at a single time point or over time has not been established. Hypothesis: That CVP measurements in healthy adult horses would be repeatable at each time point, that these readings would be reproducible over time, and that alteration in head position relative to the heart would alter CVP. Animals: Ten healthy adult research horses. Methods: In an experimental study, horses were instrumented with a central venous catheter. Readings were taken in triplicate q6h for 2 days by water manometry, and twice daily with the head in neutral, elevated, and lowered positions by electronic manometry. Results: Variation in the “neutral” measurements obtained at each time point was <0.1 ± 1.0 cmH₂O (P= .718). There was a significant decrease in CVP over time (P= .015), which was eliminated when results were controlled for acute decrease in body weight of ?1.35% (presumed hypohydration because of lack of acclimatization and decreased water intake). Head height had a significant and directional effect on CVP in that the elevated head position decreased CVP ?2.0 ± 6.5 cmH₂O (P < .001) while the lowered head position increased CVP by 3.7 ± 5.5 cmH₂O (P < .001). Conclusions and Clinical Importance: CVP values obtained by water manometry were repeatable in adult horses, but were reproducible only when controlled for changes in hydration. Care should be taken to maintain consistency in head position to prevent erroneous readings.     

Comparison of direct and indirect methods of intra‐abdominal pressure measurement in normal horses

Objectives – To develop a direct method for measuring intra‐abdominal pressures in the standing horse, identify a reference interval for direct intra‐abdominal pressures, compare these pressures to indirect intra‐abdominal pressures measured from the bladder, and determine the optimal bladder infusion volume for indirect pressure measurement. Design – Prospective, experimental study. Setting – A university‐based equine research facility. Animals – Ten healthy adult horses, 5 males and 5 females. Interventions – Direct intra‐abdominal pressures were measured through an intraperitoneal cannula and zeroed at the height midway between the height of the tuber ishii and point of the shoulder. Indirect measurements of intra‐abdominal pressure were performed by measuring intravesicular pressures through a transurethral catheter zeroed at the tuber ishii. Measurements and Main Results – Direct pressure measurements obtained in the standing horse were subatmospheric (mean, ?1.80 cm H₂O; SD, 1.61 cm H₂O; 95% CI, ?2.80 to ?0.80) and were shown to decrease as the horse's weight increased (Pearson's r=?0.67, P=0.04), with no effect of head position (P=0.15). Mean baseline indirect pressure measurements (mean, ?8.63 cm H₂O; SD, 4.37 cm H₂O; 95% CI, ?13.05 to ?4.21) were significantly different from the pressures measured directly from the abdomen (P<0.001). Indirect pressure measurements were noted to increase with increasing volumes infused into the bladder, and were statistically different at a volume of 100 mL (P=0.004). There was low to moderate correlation between direct and indirect pressure measurements of intra‐abdominal pressure over a range of fluid volumes infused into the bladder (Pearson's correlation range ?0.38 to 0.58). Conclusion – Pressures measured directly in the standing horse were subatmospheric, and increased as the horse's weight increased. Indirect pressures measured were altered by increasing volumes infused in the bladder. There was no significant correlation between the 2 methods of intra‐abdominal pressure measurement.     

Browsing of Grewia occidentalis by domestic stock in a South African savanna: the influence of bush clumps

In South African karoo categorised by multi-species bush clumps, skirted shrub species appear to physically defend the palatable shrub Grewia occidentalis against browsing by eland (Taurotragus oryx). Skirted shrubs appear to defend G. occidentalis by preventing access to plants and by reducing the accessibility of G. occidentalis foliage to the large muzzle of eland. Compared to eland, domestic stock such as goats, have a smaller body and muzzle, and these features may allow them to overcome the physical defence offered by skirted shrubs against the browsing of G. occidentalis. Our study of G. occidentalis browsed by domestic stock indicated that mature and seedling G. occidentalis typically occurred with skirted shrub species. Mature and seedling G. occidentalis growing with skirted shrubs had lower intensities of browsing than other G. occidentalis, and mature G. occidentalis growing with skirted shrubs had greater numbers of fruit than other G. occidentalis. In our study area, a non-selective grazing/browsing system is used and camps are grazed/browsed until a high proportion of forage is removed from most plants. Under this system, mature and seedling G. occidentalis are common within the study area and skirted shrubs appear to provide adequate defence for G. occidentalis against browsing by domestic stock.     

Selection for food conversion in broilers: Predicted responses to selection for economic efficiency

1. Two selection indices which included a measure of food conversion efficiency in broiler production, were formulated: one index (I₁) used individual 9‐week body weight and 5‐ to 9‐week food consumption (FC); the other (I ₂) used individual 9‐week weight and sire‐family average food consumption (FC).

2. Three empirical parameter sets and 10 hypothetical data sets were used in calculating the indices and in predicting selection responses.

3. The three empirical parameter sets gave relatively similar index coefficients for I₁ which were proportional to the relative economic weightings to the two traits.

4. Predicted economic responses to selection based on I ₂ were negligibly superior to selection for body weight alone for nearly all data sets, whereas selection based on I₁ was always superior in economic response.

5. Predicted economic response to selection based on I₁ calculated from typical published estimates of genetic parameters was 20% greater than predicted response to selection for body weight alone.     

Electrophysiological characterization of electrolyte and nutrient transport across the small intestine in horses

The aim of this study was to characterize the transport mechanisms of electrolytes and nutrients across the jejunum of nine healthy horses electrophysiologically. The stripped mucosa was mounted in Ussing chambers and tissue conductances (G_t) and short circuit currents (I_sc) were continuously monitored. After blocking the sodium and potassium channels with amiloride, tetraethylammonium chloride (TEA) and barium, chloride secretion was stimulated by carbachol and forskolin. Subsequently, chloride channels were inhibited by 4,4′‐diisothiocyanato‐stilbene‐2,2′‐disulfonic acid, 5‐nitro‐2‐(3‐phenylpropylamino)benzoic acid, CFTR_inh‐172, N‐(2‐naphtalenyl)‐(3.5‐dibromo‐2.4‐dihydroxyphenyl)methylene glycine hydrazide (GlyH‐101) and glibenclamide and their dose–response effect was investigated. The response to glucose, l ‐alanine and glycyl‐l ‐glutamine was determined at two different mucosal pH values (pH 7.4 and 5.4 respectively). Mean basal I_sc was ?0.47 ± 0.31 μEq/cm²h and mean G_t was 22.17 ± 1.78 mS/cm². Amiloride and TEA did not alter the baseline I_sc. Barium, carbachol and forskolin significantly increased I_sc. Irrespective of the dose, none of the chloride inhibitors changed I_sc. All nutrients induced a significant increase in I_sc with the increase being significantly higher at pH 7.4 than at pH 5.4. In conclusion, there is evidence that chloride secretion in horses may be different from respective transport mechanisms in other species. The glucose absorption is suggestive of a sodium‐dependent glucose cotransporter 1. However, a decrease in luminal pH did not stimulate current response to peptides as shown for other mammals.     

Estimation of the total surface area in Indian elephants (Elephas maximus indicus)

Twenty-four adult Indian elephants (Elephas maximus indicus) of both sexes and different ages and weights, belonging to the Temple Devaswoms, the Forest Department of the Government of Kerala and the Gemini Circus formed the experimental subjects from which formulae were derived to predict the total surface area from either body measurements or areas of individual regions. Several models, using the parameters studied either singly or in combination, were tried independently for males and females and also for adults irrespective of sex. The best prediction of total surface area (S) in m² was obtained for adults irrespective of sex by using the two parameters, the height at the shoulders (H) in m and forefoot pad circumference (FFC) in m in the formula S=–8.245+6.807H+7.073FFC. No significant improvement in the accuracy of prediction resulted from the use of the independent best fit formulae for males and females. The conventional method of using the exponential of body weight (kg) for predicting suface area was not found to yield an equivalent accuracy in these animals.     

Efficacy of Sex Determination in the Greater Cane Rat,Thryonomys swinderianus,Temminck

The efficacy of the two most common techniques used for determining the sex of the greater cane rat, Thryonomys swinderianus, Temminck, was tested using 10 young and 8 adult animals with two technicians at the Animal Research Institute's Grasscutter Domestication Centre, Pokoase, Ghana. The techniques compared were the use of the head shape and/or head size and the use of the ano-genital distance. The use of the ano-genital distance for sex determination was validated in a colony of greater cane rats at various stages of development, i.e. from the day of birth to three or more years of age. The ano-genital distance was then used as the standard against which the use of the head shape and/or head size technique was tested. The results indicated that the use of the ano-genital distance for sex determination in the greater cane rat was error-free, even with little experience on the part of the practitioner. The ano-genital distance was more than twice as long in the males than in the females at all ages (p<0.001). However, the use of the head shape and/or head size for sex determination was found to be associated with some degree of error in both sexes. The use of the ano-genital distance can therefore be recommended as an efficacious technique for sex determination in the greater cane rat.