Effects of castration on growth performance and carcass characteristics of Awassi lambs fed high concentrate diet

Relationships between body condition score, body weight and body measurements in alpacas

BACKGROUND

The nutritional status in alpacas is often masked by their dense fibre coat. Its assessment is commonly approached by different body condition scores (BCS) that rely on manual palpation of defined anatomical regions. However, BCS is an important diagnostic tool to aid recognition of diseased South American camelids (SACs) and low BCS has been associated with conditions like anaemia and neutrophilia. For dose-dependent veterinary treatment, body weight (BW), that should be as accurate as possible, is required. As on-site weighing with scales is often not possible, BW can mostly only be roughly estimated. To date, it remains unclear whether BCS in alpacas provides reliable information on BW or the ratios of BW to body length commonly known as Body Mass Index (BMI) or Ponderal Index (PI). Equations to estimate BW based on body measurements are available in the literature. Nonetheless, respective equations were developed in growing alpacas or adult llamas and BCS was not included.

RESULTS

To compare six different BCS approaches and to examine the relationship between BCS and BW, body measurements and BCS scores were recorded in a herd of 105 alpacas. The examined BCS approaches showed significant (p < 0.05) but poor to moderate positive correlations to BW, BMI or PI. A solely visual inspection of BCS, in contrast, was not correlated with BW, BMI or PI. Equations previously developed in other studies provided an accurate estimation of BW. Multiple linear regression showed that the accuracy in predicting BW could be further increased by adding BCS data and sex.

CONCLUSION

Our observations indicate that most selected BCS approaches are not only important measures of nutritional status but can also be used to create more accurate models for BW calculation in alpacas. The study also supports the claim that a purely visual inspection of alpacas is not an adequate method to evaluate the nutritional status of these animals.

Production Characteristics and Management Practices of Indigenous Tswana Sheep in Southern Districts of Botswana

The aim of this study was to describe the indigenous Tswana sheep production systems, their management and farmers’ preferred selection traits when selecting breeding rams in four southern districts of Botswana. A total of 105 households; Kgatleng (n = 30), Kweneng (n = 27), southern (n = 24) and south–east (n = 24) districts were interviewed using structured questionnaire. An index-based approach was used to rank farmers’ most preferred traits for their production systems. Data were analyzed using Statistical Package for Social Sciences. The Chi-square test was used to assess the statistical significance among categorical variables. The results indicated that indigenous Tswana sheep are mainly kept by males, single people, aged between 51 and 60 years possessing primary and secondary education. Management practices across the districts include castration, health care and supplementation mostly during the dry season. Superior fitness traits of indigenous Tswana rams over exotic rams were considered more important when selecting breeding rams in Kgatleng, Kweneng and south–east while in the southern district, rams were mainly selected based on body size. Most farmers kept breeding rams while those who did not keep rams depended on communal rams for service. This information is important in designing successful breeding programs and strategies for the conservation and sustainable utilization of indigenous Tswana sheep genetic resources.

Partial substitution of barley for corn: effect on "Hamra" lamb growth performance, carcass and meat characteristics

The aim of this study was to investigate the effect of two kinds of given diets on growth, on some carcass characteristics and on the major meat nutrients of local Algerian sheep breed. The investigated sheep breed called "Hamra" is one of the most famous breeds in Algeria. Among one 106 animals, 40 lambs were selected according to their age, similar livestock characteristics and body weight. The samples were divided into two equal groups: control and experimental lambs according to their live weight; 24.63 ± 0.47 and 24.35 ± 0.64 kg, respectively. Both groups were fed with two varieties of concentrate diets: corn diet based for the first group of control lambs (n = 20) and corn substituted by barley (Variety Saïda 183) for the second experimental group lambs (n = 20). Both diets were supplemented with 200 g straw of barley/animal/ration. The chemical analysis of diets showed an elevated crude fibre content in the commercial concentrate. However, the experimental concentrate contained higher amounts of calcium. After 59 days of fattening, no significant difference was found among the two studied groups on the growth performance (p > 0.05), showing the same final body weight. In contrast, a significant difference was found (p ≤ 0.001) in relation to the cost of the given diet. This could affect the price of the produced meat. At 37.85 ± 0.78 kg live weight, 10 lambs fed with experimental concentrate were slaughtered. The dressing percentage was 46.65 %, with 2.49 % of carcass shrink. Furthermore, an interesting percentage of total muscle was obtained (63.73 %) with a good carcass conformation scoring 9.56. Compared to other breed sheep, Hamra carcass could be considered as the most valuable one economically.

Quantification of the effects of castration on carcass and meat quality of sheep by meta-analysis

After an extensive literature search, meta-analytic techniques (fixed effect, random effects and hierarchical Bayesian models) were applied to numerically describe sizes and precision of effects caused by castration of intact rams on several performance, carcass and meat quality response variables. According to random effects models, rams presented greater (P<0.05) average daily gain, loin muscle area (leaner carcasses) and instrumental meat tenderness (more tough), with lower feed conversion ratios, dressing percentages and backfat thickness (less carcass fat) compared to castrates. These results could be applied in further strategies on the use of castration in male sheep.

Performance and carcass characteristics of intact and castrated male Black goat kids fed diets of various energy levels

Thirty Black goat male kids were used in a 3 × 2 factorial arrangement to evaluate the effects of three dietary energy levels (EL) and early castration (TRT) on growth performance, body and carcass characteristics. Upon weaning at 90 days of age, kids were randomly divided into three equal groups (n = 10: five intact and five castrated) and assigned to one of the three dietary treatments containing 15% CP and different energy levels: low (LEL; 10.44 MJ ME/kg DM), medium (MEL; 11.60 MJ ME/kg DM) and high energy (HEL; 12.90 MJ ME/kg DM). Kids were individually fed on an ad libitum basis and were slaughtered at the end of the fattening period. Results showed no differences between castrated and intact kids in feed and nutrient intake. The level of dietary energy affected dry matter intake (P < 0.05), metabolisable energy intake (P < 0.01), crude protein intake (P < 0.05), neutral detergent fibre (P < 0.001) and acid detergent fibre intakes (P < 0.001). Dry matter intake was 280, 305 and 264 g/kg W0.75.day for kids receiving LEL, MEL and HEL diets, respectively. Metabolisable energy intake was the highest for kids receiving the MEL diet (0.90 Mcal/kg W0.75.day) compared with LEL (0.73 Mcal/ kg W0.75.day) and HEL (0.88 Mcal/kg W0.75.day) diets. Final liveweight and average daily gain (ADG) were greater (P < 0.01) in MEL diets. Kids fed MEL gained 133 g/day, while ADG values were 92 and 100 g/day for kids fed LEL and HEL diets, respectively. Total muscle percentage was greater (P < 0.05) for kids fed MEL diets (55.9%) compared with LEL (53.8%) and HEL (51.1%) diets. Castrated kids had lower (P < 0.01) carcass muscle percentage, but higher carcass (P < 0.01) and subcutaneous (P < 0.001) fat percentages than intact kids. It can be concluded that the best growth performance was observed in kids receiving the MEL with no differences between castrated and intact kids. Castration influenced accretion of fat in castrated kids.