Growth performance,carcass characteristics and meat sensory evaluation of West African dwarf sheep fed varying levels of maize and cassava hay

A study was conducted to determine the growth performance and meat yield and quality of West African dwarf sheep. Twenty rams weighing an average of 15.3 ± 0.79 kg live weight and with an average age of 18 months were allotted at random to five dietary treatments of 0%, 25%, 50%, 75% and 100% maize hay (MH) for a period of 105 days. Dry matter (DM) intake and growth rate of the rams were improved as the level of cassava hay (CH) increased in the diets. Live weight gain varied significantly (P < 0.05) across the treatments, ranging from 38.8 to 47.9 g/day. The carcass weight of the rams fed 100% MH was significantly (P < 0.05) lower compared with the other treatments. Dressing percentage ranged from 56.5% to 61.0% with no significant (P > 0.05) difference observed across the treatments, while the distribution of the slaughtered parts was similar (P > 0.05) regardless of the dietary treatment. Proximate composition of the meat from the loin indicated that the DM, crude protein, fat and ash contents were not influenced (P > 0.05) by the dietary treatments. Panellists rated the meat to be similar (P > 0.05) in flavour, juiciness, tenderness and overall acceptability while colour and texture varied significantly (P < 0.05) across the treatments. In conclusion, this study indicated that better growth performance and meat production in West African dwarf sheep can be improved in form of body weight and carcass production when fed 25%MH and 75% CH diet.     

Effect of oxytocin on suppression of oestrus in mares exhibiting normal oestrous cycles

Abstract

AIM: To compare the efficacy of oxytocin given once daily, either I/V or I/M, on Days 7–14 post-ovulation, on the expression of oestrus in mares through to 65 days post-ovulation.

METHODS: Eighteen mares of various breeds that were displaying normal oestrous cycles were randomly assigned to one of three treatment groups on the day of ovulation (Day 0), detected using transrectal ultrasonography. Mares in the control group (n = 6) were given 1 mL saline I/V; mares in the I/V and I/M groups (n = 6 per group) were injected with 10 IU oxytocin I/V and I/M, respectively. All treatments were given once daily on Days 7–14. Mares were teased by a stallion three times per week, up to 65 days post-ovulation, to detect oestrous or dioestrous behaviour. Ovarian follicular and luteal activity were monitored using transrectal ultrasonography three times weekly, and daily when a follicle >30 mm diameter was present until ovulation. Blood samples were collected weekly for analysis of concentrations of progesterone in serum. Prolonged dioestrus was defined as a period of >30 days of dioestrous behaviour after Day 0, confirmed by detection of corpora lutea and concentrations of progesterone in serum >4 nmol/L.

RESULTS: Overall, 8/18 (44%) mares showed prolonged dioestrus. These included 2/6 (33%) mares in the control group, compared with 5/6 (83%) and 1/6 (16%) mares in the I/V and I/M groups, respectively (p = 0.11). The median duration of the first dioestrus was longer for the I/V group (64 (min 16, max 66) days) compared with the control group (18 (min 12, max 64) days) (p = 0.05), but was not different between the control group and the I/M group (16 (min 13, max 65) days) (p = 0.57). For all mares there was strong agreement between teasing behaviours, ultrasonographic assessment of ovarian activity, and concentration of progesterone in serum.

CONCLUSIONS AND CLINICAL RELEVANCE: This study found that low doses of oxytocin did not increase the proportion of mares with prolonged dioestrus, compared with controls, although I/V oxytocin did increase the median duration of dioestrus. The results must be interpreted with some caution as group numbers were small, and a variety of breeds were used. Further investigation of oxytocin given I/V may be warranted as a potential method of oestrus suppression in mares exhibiting oestrous cycles that is low cost, safe and well-tolerated, and potentially reversible with prostaglandin.     

The effect of two different weaning procedures on the growth of pasture-reared Thoroughbred foals in New Zealand

AIM: To identify if there was a significant difference in the average daily liveweight gain (ADG) between Thoroughbred foals weaned using two weaning protocols commonly used in New Zealand.

METHODS: Sixteen Thoroughbred foals were blocked for sex and age, randomly allocated into progressive (187, SD 33 days; three colts, five fillies) or abrupt (182, SD 28 days; four colts, four fillies) weaning groups, and weighed every second day for 2 weeks either side of weaning, then fortnightly from birth to 480 (SD 31) days old. ADG was calculated to examine the short-term (10 days before weaning, 5 and 10 days post weaning) and long-term (0–6 and 6–16 months of age) effect of the two weaning treatments.

RESULTS: ADG was 1.10 (SD 0.091) kg/day before weaning (0–6 months of age) and 0.59 (SD 0.06) kg/day from weaning to 480 (SD 31) days old. At the start of weaning, liveweights of the progressive and abrupt weaning groups were 276.5 (SD 40.3) kg and 257 (SD 15) kg, respectively (p=0.23). For the 5-day period during weaning, irrespective of treatment, there was a significant decrease in ADG of –0.29 (SD 0.49) kg/day and –0.15 (SD 0.30) kg/day for progressive and abrupt weaning, respectively. There was no significant difference in ADG between weaning methods at any measurement period (short or long term) during and after weaning. However, there was large variation between foals in ADG in the 10 days after the weaning process, which may indicate variation in individual foals' responses to being weaned, rather than the weaning treatment.

CONCLUSIONS: Weaning, irrespective of method, was associated with a decrease in ADG in the first week after weaning. The method of weaning had no effect on post-weaning ADG either short term, 10 days after weaning, or long term up to 480 days of age. Practically, it may be more important to consider maturity and liveweight as criteria for weaning foals rather than age alone.     

Patterns of Parturition and Mortality in Weaned Greater Cane Rats (Thryonomys swinderianus,Temminck)

The patterns of parturition and mortality were studied in a colony of weaned captive greater cane rats, Thryonomys swinderianus, Temminck, from January to December 2000 at the Grasscutter Domestication Centre, Pokoase Research Station, Animal Research Institute, Ghana. The most important finding from the study was that it is practical to wean greater cane rats at 4 weeks of age with proper post-weaning management. Mortality ranged between 0 and 3.9% with an average of 1.4% for animals weaned at 4 weeks. Among the factors contributing to mortality in the weaned greater cane rats may be the number of animals per unit space. The mortality in this study was a marked improvement compared to that of 11% reported elsewhere for animals weaned at 6 weeks. The animals were, however, smaller at weaning compared to those in reports from elsewhere, probably owing to poor lactation by the mothers. Peak parturition occurred in October with captive breeding having no influence on the parturition pattern.     

Inactivated oil emulsion vaccines from selected clones of Newcastle disease virus

The immunogenicity of oil emulsion (OE) vaccines prepared from two selected clones of a Nigerian strain of Newcastle disease virus and two commercial vaccine strains were compared. Geometric mean haemagglutination inhibition titre was lowest in OE-Lasota, although all four vaccines gave 100% protection against clinical Newcastle disease. The use of OE vaccines is recommended for commercial use in Nigeria.     

Protective levels of canine distemper virus antibody in an urban dog population using plaque reduction neutralization test

Blood samples from 50 dogs were collected at three veterinary clinics in Ibadan and Abuja, Nigeria and the serum from each sample was evaluated serologically for neutralizing antibodies against canine distemper virus (CDV) by the highly sensitive plaque reduction (PRN) neutralization assay. Thirteen dogs had plaque reduction neutralization titres of 0-100, seven had titres of 100-1,000 while 30 had titres ranging from 1,000-6,000. The PRN titres of vaccinated dogs were found to be significantly higher than unvaccinated dogs. The widespread use of the highly reproducible PRN test for the evaluation of antibody response to CDV may be very important in the generation of international CDV positive serum standards that should help to improve pre-and post-vaccination testing of dogs worldwide.     

The Efficacy of the Vaginal Plug Formation after Mating for Pregnancy Diagnosis,and Embyonic Resorption In Utero in the Greater Cane Rat (Thryonomys swinderianus,Temminck)

The efficacy of the detection of vaginal plug formation after mating for pregnancy diagnosis, and the degree of embryonic resorption were studied in 67 wild greater cane rats (Thryonomys swinderianus) at Esiam in the Ekumfi District, Ghana, over a period of 3 months. Vaginal plug formation was first observed on day 59 of gestation, and could be used for pregnancy diagnosis on or after that date. However, the vaginal orifice subsequently opened a couple of times prior to day 105 of gestation and further checks for pregnancy after day 59 of gestation are suggested. Animals with unplugged vaginas 105 days after mating could, however, be considered as not pregnant. The mean (±SE) number of implantation sites and litter size in the greater cane rat were 7.2±0.18 and 3.4±0.29, respectively, the embryonic resorption rate being 42.7±6.66%. The significant positive correlation between the number of implanted embryos and the bled-out carcase weight suggests a positive role of maternal nutrition in increasing the litter size in the greater cane rat. The incidence of post-partum oestrus during the study period was 42.1%, which suggests that the greater cane rat can be re-bred immediately after parturition.     

Reproduction and Mortality in a Colony of Captive Greater Cane Rats,Thryonomys swinderianus,Temminck

The reproductive performance and mortalities in a colony of captive greater cane rats, Thryonomys swinderianus, were monitored from 1992 to 1998 at the Grasscutter Domestication Centre, Achimota, Ghana. The animals were kept in cages and exposed to constant lighting from a 100 W electric light bulb during the night. The diet consisted mainly of freshly cut Panicum maximum (guinea grass) fed ad libitum, with occasional supplements of cassava and cane sugar. The results indicate that the mean litter size and litter weight were 2.9±0.51 and 439.4±81.23 g, respectively. These figures are low compared to those reported elsewhere. However, the mean birth weight was 151.2±11.08 g, higher by 12% than previously reported values. It is considered that poor nutrition, excessive exposure to light and stress were responsible for the relatively poor reproductive performance reported in these animals. The main causes of death were traumatic injuries (32%) and pulmonary congestion (16%).