Growth and reproductive performance of two rabbit breeds reared under intensive system in Ghana

A study on the growth and reproductive performance of two rabbit breeds was undertaken. Data on 588 kits and 97 does of California White and 574 kits and 90 does of New Zealand White rabbits reared under hot and humid environment in Ghana were taken. The reproductive performance of the two breeds, in terms of litter size at birth and weaning, litter weight at birth and weaning, kindling interval, age at sexual maturity, and gestation length as influenced by breed, season of kindling (rainy and dry), year of kindling (2005–2012), and parity (first to sixth and over) were determined. The performance of California White in terms of litter size at birth, at weaning, kit weight at birth, and age at first kindling was 5.9?±?0.2, 4.6?±?0.1, 54.7?±?0.4 g, and 159.8?±?0.2 days, respectively. That of New Zealand White was 5.9?±?0.1, 5.1?±?0.1, 55.2?±?1.0 g, and 159.9?±?0.2 days, respectively. The results obtained also showed a significant breed effects on kit weight at birth, litter weight at weaning, and mortality; whereas no significant differences (p?>?0.05) were observed between the two breeds regarding the other traits measured. Parity had significant effects (p?<?0.05) on all the growth and reproductive parameters measured with the exception of age at first kindling. Year of kindling also had significant effect on litter weight at birth, kit weight at birth, and at weaning (p?<?0.05) but did not have any significant effect on the age at sexual maturity and mortality. Season also had significant (p?<?0.05) effects on kit weight at birth, gestation length, kindling interval, and mortality with better performance experienced during the rainy season.

     

Analysis of size and conformation of native Creole goat breeds and crossbreds used in smallholder agrosilvopastoral systems in Puebla,Mexico

Liveweight (LW) of does and bucks of the native Creole goat breed and crosses of Creole does and Nubian bucks, aged 1.5–5 years, were recorded and body traits including: head length (HL), head width (HW), body length (BL), trunk length (TL), chest girth (CG), abdominal perimeter (AP), rump length (RL), and height at withers (HW) were measured to develop equations for predicting LW from the body measurements. Weight, sex, breed and kidding date of 354 kids were recorded at birth, and LW of the kids was measured monthly for one year to determine the effect of kidding season on growth rate. Bucks had higher (p < 0.05) body measurements than the does (HL 15.1 ± 0.1 vs 16.6 ± 0.2 cm; BL 97.6 ± 0.4 vs 104.6 ± 1.2 cm; CG 78.8 ± 0.4 vs 79.9 ± 1.0 cm; AP 82.4 ± 0.5 vs 87.2 ± 1.1 cm; HW 62.7 ± 0.4 vs 70.1 ± 0.8 cm). With the exception of TL, F₂ does had higher (p < 0.05) body measurements and LW (28.8 ± 1.5 vs 27.7 ± 0.5 kg) than Creole does. The body traits of the F₁ does were similar (p > 0.05) to those of Creole does with the exception of HL, BL and HR. The F₂ kids were heavier (p < 0.05) at birth (3.31 ± 0.1 vs 2.60 ± 0.1 kg) and grew faster than the Creole kids. Male kids were heavier (p < 0.05) at birth (3.21 ± 0.10 vs 2.73 ± 0.13 kg), and grew faster than female kids. Season had a significant effect on birth weight. The results showed that LW of Creole goats and Creole × Nubian does could be estimated in the field using body traits. Birth weight and growth rate of kids could be improved by management practices that affect season of kidding.     

Concentrate supplementations of grazing pregnant Kalahari Red goats: Effects on pregnancy variables,reproductive performance,birth types and weight of kids

A study was conducted for 22 weeks to determine the effects of concentrate supplementations at three crude protein (CP) levels, i.e. low protein diet—LPD 12.42% CP (124.93 g day^?1); medium protein diet—MPD 14.18% CP (145.87 g day^?1) and high protein diet—HPD 16.35% CP (168.19 g day^?1) on some pregnancy variables, reproductive performance, birth types and weight of kids kidded by pregnant Kalahari Red goats grazed on Chloris gayana. Thirty-three matured Kalahari Red goats of first parity within age range of 2 to 2¹/₂ years with an average body weight of 38.10 ± 1.13 kg were randomly allotted to the diets with 11 goats per treatment. Data obtained were subjected to analysis of variance in a completely randomised design. It was observed that goats fed HPD had the highest (p < 0.05) values for products of pregnancy (10.35 kg) taken within 24hour before kidding and foetal growth rate (88.37 g day^?1) during pregnancy. Goats fed MPD had the lowest values (p < 0.05) of 9.28 kg and 80.07 g day^?1 for each of the respective parameters. Afterbirth weight was also the highest and lowest (p < 0.05) for goats supplemented with HPD (3.38 kg) and MPD (3.04 kg), respectively. On the other hand, MPD-supplemented goats had the highest values (p < 0.05) for litter size (2.14) and litter weight (6.80 kg) at birth, the value which was the least for HPD supplementation. From the results obtained from this study, it could be concluded that concentrate diet supplementation with 14.18% CP improved litter size and weight at birth with resultant reduction in weights of pregnancy variables of pregnant Kalahari Red goats grazed on Rhodes grass.     

Behaviour of crossbred does and their kids at parturition under extensive and intensive conditions

Data from 82 kiddings from mixed-breed (native x dairy goats) goats reared on rangeland (n = 47) or confinement (n = 35) were used to determine the influence of various factors on length of labour, standing of newborn kids and time to first suckling in pluriparous goats. Both groups were mated at the same time to bucks of the same genotype in February. During the kidding time in July, the goats were monitored for 24 h in order to register parturition traits and kid birth weight and body measurements. For all goats, blood samples were collected at parturition in order to establish the nutritional state of goats. Grazing goats had lower body weight and body condition score (P < 0.01) than pen-fed goats, as well as lower values for some blood metabolites indicative of low body energy reserves. For both grazing and pen-fed goats, the majority of kiddings (>93%) occurred during daylight hours. No kiddings were registered from 2300 to 0500 hours. No effects of height at withers, thoracic circumference and sex of kids at birth were found to influence length of labour. Labour was shorter (P < 0.01) for pen-fed does than grazing goats (10.6 ± 1.18 min vs. 15.4 ± 1.2 min; mean ± SD). The length of parturition was considerably longer (P < 0.05) for twin-bearing does than for single-bearing does (16.6 ± 1.76 min vs. 11.2 ± 0.81 min, respectively). The interval between parturition and standing of kids was shorter (P < 0.05) for kids from litters weighing >3.3 kg (entire litter) than kids from litters with <3.3 kg (22.7 ± 1.82 min vs. 31.1 ± 2.76 min). Time to first suckling was longer (P < 0.05) for kids delivered from pen-fed does than kids from grazing does (57.8 ± 7.57 min vs. 42.9 ± 3.05 min). These results confirm that, independently of type of production system (intensive or extensive), kiddings of does are concentrated during daylight hours. These results also indicate that conformation of kids does not alter duration of labour, and that nutritional stress of goats during gestation (extensive conditions) does not interfere with the neonate’s level of alertness and arousal.     

Non-genetic factors affecting reproductive traits in Lohi sheep

Abstract

The data on breeding and performance records (3830) of 1134 Lohi ewes kept at an Institutional Livestock Experiment Station, Okara in Punjab province during the period from 1972 through 2001 were used to study the influence of some non-genetic factors such as year and season of birth/lambing, age and weight at first service sex of lamb born, birth type, age of dam on various reproductive traits. The age of ewes at first service averaged 615.6±8.2 days and was not significantly affected by the year and season of birth of the ewes. The ewes born during spring season had comparatively low (613.6±7.9 days) age at first service than autumn born (617.5±9.8 days). The type of birth did not significantly influence age at first service. The least squares mean for the weight at first service was 42.10±0.24 kg and was significantly (P<0.01) influenced by the ewe's year and season of birth. The spring-born ewes were heavier (42.3±0.3 kg) at first service than autumn-born ewes (41.9±0.3 kg). The weight at first service was also significantly affected by the age at first service. The type of birth did not significantly influence weight at first service. The number of services per conception averaged 1.29±0.03 and varied significantly (P<0.01) between seasons. The number of services per conception was higher (1.37±0.02) in ewes bred during autumn than those bred in spring (1.16±0.06). The effects of years and weight at service on the number of services per conception were non-significant. The number of services per conception significantly increased with advancing age. Mean gestation period was 152.31±0.08 days and it was significantly affected by the years and seasons of lambing and the age of the ewe at lambing. However, gestation length was not significantly affected due to birth type and sex of the lamb born.     

An investigation into uterine capacity based on litter and placental characteristics in two sow lines with different prolificacy (Danish Landrace x Danish Yorkshire versus German Saddleback)

Litter size in modern so called hyperprolific pig (Sus scrofa Linnaeus) breeds such as of crossbred Danish Landrace x Danish Yorkshire (LY/YL) sows increased remarkably over recent years, however, commonly associated with reduced piglet birth weight and higher within litter birth weight variability likely due to a limited uterine capacity. Since investigation into this issue is patchy, the aim of this study was to investigate uterine capacity based on litter and placental characteristics in two sow lines with different prolificacy, that is crossbred Danish genetic (Danish Landrace x Danish Yorkshire; DG; n = 14) and purebred German Saddleback (GS) sows (n = 12). Parameters recorded were litter size, piglet birth weight and vitality, placental weight and surface area as well as placental vascularization. Litters of DG were on average larger than of GS (p < .001). Piglets of DG weighed on average less than GS (p < .001) and were less vital (p < .001–.142). Increasing litter size was associated with reduced piglet birth weight and increased within litter birth weight variability in GS, but not in DG. DG had on average a lower placental weight (p < .001) and smaller placentae (p < .001) than GS, but the placenta was on average more efficient than of GS (based on the quotient of piglet and corresponding placental weight; p < .001). Vascularization of placentae was on average not or only slightly different between breeds (p < .05 – .982). Remarkably, however, vascularization of the lateral and apical chorionic epithelium of the chorionic ridges as the immediate foetal/maternal interface was on average slightly higher in DG than GS (p < .05–.111). Results thus demonstrate that uterine capacity based on litter and placental characteristics is higher in DG than GS sows.     

A retrospective study of female reproductive parameters in the Kunming dog

The Kunming dog is the first and only working dog breed from China to be recognized worldwide. As a domestic working dog, its excellent working performance has been well established; however, its normal reproductive parameters are not well understood. Therefore, this study was conducted to document the main reproductive parameters of this purebred working dog in field breeding conditions. Data on 1004 heats (753 with mating) from 203 bitches between 2008 to 2014, were collected and analyzed. The pregnancy rate and whelping rate was 79.42% and 75.30%, respectively. Finally, for 567 litters (4298 puppies), the mean litter size was 7.19 ± 0.12 puppies (range 1–15). The mean gestation period and birth weight were approximately 61.64 ± 0.10 days and 407.25 ± 1.21 g. The mean sex ratio was 1.03 males to 1.00 female. Estrus occurred throughout the year with no significant differences between seasons and months (P > 0.05), which confirms that Kunming dogs are non‐seasonal breeders; births occurred in every month of the year. Pregnant bitches exhibited significantly longer inter‐estrus intervals than non‐pregnant bitches (220.85 ± 2.05 vs. 180.19 ± 2.94 days, P < 0.05). Bitch parity influenced litter size, and the gestation length and birth weight of the puppies were negatively affected by litter size. This study helps elucidate the reproductive potential of this breed and provides reference values for reproductive performance in the Kunming dog.     

Variance components and genetic parameters for weight and size at birth in the Boer goat

Variance components, heritability (direct additive and maternal) and correlations (additive genetic, phenotypic, maternal genetic and environmental) of body weight (BW) and body size including length (BL), height (BH) and chest girth (BCG) at birth in Boer goats were estimated on the basis of 5096 records obtained from a Boer Goat Breeding Station in Yidu, China, during 2001–2005. The parameters were estimated using a DFREML procedure by excluding or including maternal genetic or permanent maternal environmental effects, four different analysis models were fitted in order to determine the optimum model for each trait. The environmental factors such as year, season, sex and litter size (LS, number of kids) were investigated as the fixed effects. The results showed that the maternal effects were important determinants of estimated the genetic parameters for birth traits. Year and season had significant effect on birth traits. Single births and male kids had the heaviest live weight and the largest body size at birth. The mean values and standard deviation (SD) of BW, BL, BH and BCG were 3.87 ± 0.85 kg, 31.67 ± 2.87 cm, 32.92 ± 2.80 cm, 33.46 ± 3.21 cm. The mean values and standard error (SE) of direct additive heritability estimates for BW, BL, BH and BCG calculated with the optimum model were 0.19 ± 0.08, 0.14 ± 0.07, 0.24 ± 0.09 and 0.25 ± 0.10, respectively. For all the birth traits, estimates of the correlations between direct additive and maternal genetic (r_a–m) were negative. The estimates of additive genetic and phenotypic correlations among the birth traits were high and positive, and implied no genetic antagonisms among these traits analyzed. The estimates of maternal genetic correlations also were high and positive. Medium and positive environmental correlations indicated the important effects of environmental factors on early growth traits.     

Causes of lamb morbidity and mortality in the Ethiopian highlands

A study was conducted to investigate causes of lamb morbidity and mortality on farms and on-station at Debre Berhan during 1989 and 1990. It showed pneumonia (bacterial and/or verminous), starvation-mismothering exposure (SME) complex, gastrointestinal parasites, enteritis, abomasal impaction and physical injuries to be important health constraints on productivity. Neonatal mortalities were 51.5% and 46.3% on farms and on-station respectively and occurred owing to management problems such as SME, abomasal impaction and physical injuries. On the farms the lamb birth weight was 2.56±0.25 kg and was significantly (p<0.05) affected by the dam's age, lambing weight, litter size, sex of lamb and year of lambing, but not by the season of lambing. Birth weight significantly (p<0.05) influenced lamb mortality. Lambs with a low birth weight tended to die from SME. Morbidities and mortalities due to infectious causes increased in older lambs, suggesting that infections were acquired with age when resistance was lowered owing to inadequate nutrition and poor management.Heavy loss of lambs could be overcome by such health management interventions as foster mothering, warming lambs during the cold season and vaccination with polyvalent vaccines against pasteurellosis, clostridial infection andDictyocaulus filaria.     

Vigour in West African Dwarf kids within the first 24 h post-partum

One hundred and fifty West African Dwarf (WAD) kids were tested at the National Goats Breeding Station to determine the effects of some neonatal factors on their vigour levels within the first 24 h post-partum. The kids were also tested to establish the relationship between maternal weight, rectal temperature, times of first standing and sucking, sucking period and vigour. The distance covered (in meters) by a kid towards its mother during a 5-min test period was considered as vigour trait. Vigour levels increased significantly (p?<?0.05) with increasing age within the first 24 h post-partum. Kids born to second parity mothers had higher (p?<?0.05) vigour than those born to first parity mothers. Similarly, high birth weight kids had higher (p?<?0.05) vigour levels than low birth weight kids. Weak positive and negative correlations (p?<?0.05), respectively, were found between vigour and rectal temperature, and vigour and the time of first successfully standing. However, there was moderate positive correlation (p?<?0.01) between vigour and sucking period. The time it took for the newborn kid to stand up for the first time also correlated weakly and negatively (p?<?0.01) with the duration of sucking by the newborn within the first 5 min of accessing the teat. Vigour within the first 24 h post-partum in WAD kids increased with increasing age, parity and birth weight and might be responsible for the earlier and longer sucking time and periods, respectively, in high birth weight kids and those dropped by multiparous does.     

Reproductive Performance and Milk Production of Damascus Goats Fed Acacia Shrubs or Berseem Clover Hay in North Sinai,Egypt

Thirty-three adult Damascus does (29±1.1 kg BW) were fed 0.6 kg per head per day of a concentrate diet plus ad libitum rice straw (Oryza sativa, control, R), or green acacia (Acacia saligna, A) or berseem clover hay (Trifolium alexandrinum, B). All treatment groups had free access to underground saline water containing 3600 ppm TDS. The DM intake was lower (p<0.05) for the R group but did not differ between the other two groups. The DM intake of acacia was 0.64 kg per head per day (1.98% BW) during pregnancy and 0.93 kg per head per day (2.95% BW) during lactation. The drinking water differed (p<0.05) between the three dietary treatments; group B had the highest mean intake and group A had the lowest. The percentage kidding and the litter weight at birth did not differ significantly between the groups. However, the number of kids weaned/doe kidding and the weight of the kids weaned/doe kidding were significantly higher for group B. The mean body weight of the kids at birth and at weaning were significantly lower for group R. The total milk yield over 10 weeks and the milk composition (total solids, fat and protein percentages) were significantly different between the three groups; group B having the highest means and group R the lowest. These results suggest that supplemental feeding is required to enhance the productivity of goats in arid or semi-arid environments and Acacia saligna should not be used fresh in excessive quantities for extended periods.     

Influences of non-genetic factors on early growth of Adilo lambs under smallholder management systems,southern Ethiopia

Stagnant early growth and mortality are the major impediments for sheep production in southern Ethiopia. We evaluated the effects of non-genetic factors on early growth performance of lambs in Halaba district with 467 lambs owned by 60 households. Body weights (kilograms) of lambs at birth, 30, 60, 90, 120, and 150 days were 2.30 ± 0.03, 4.45 ± 0.11, 6.94 ± 0.13, 10.4 ± 0.19, 13.3 ± 0.19, and 15.7 ± 0.20, respectively. The average daily gain (ADG; gram) from birth to 30, 60, 90, 120, and 150 days were 71.18 ± 8.18, 77.18 ± 2.19, 89.20 ± 1.98, 91.18 ± 1.51, and 90.68 ± 1.27, respectively. Season effect was significant (p < 0.05) for weight at birth, 30, and 120 days. Similarly, season of birth influenced (p < 0.05) ADG (gram) at all ages except from birth to 60 days. Single-born lambs were heavier over multiple births (p < 0.01), 90 (p < 0.001) and 120 days (p < 0.05) and higher (p < 0.001) ADG from birth to 90 days. There were significant interaction effects of parity by sex at birth (p < 0.01) and parity by type of birth (p < 0.001) and 90 days (p < 0.01). From the non-genetic factors estimated in this study, season and type of birth, and their interaction had a more profound effect at early growth of lambs, and they need to be considered in the improvement plan of sheep under Halaba arid to semi-arid environments. Efforts geared towards planned breeding, improved nutrition, and health would assist farmers to exploit these indigenous and adaptable sheep resources efficiently.     

Estimation of the optimal standardized ileal digestible lysine requirement for primiparous lactating sows fed diets supplemented with crystalline amino acids

This experiment was conducted to determine the optimal standardized ileal digestible lysine (SID Lys) level in diets fed to primiparous sows during lactation. A total of 150 (Landrace × Large White) crossbred gilts (weighing 211.1 ± 3.5 kg with a litter size of 11.1 ± 0.2) were fed lactation diets (3325 kcal metabolizable energy (ME)/kg) containing SID Lys levels of 0.76, 0.84, 0.94, 1.04 or 1.14%, through 28 days lactation. Gilts were allocated to treatments based on their body weight and backfat thickness 48 h after farrowing. Gilt body weight loss was significantly (P < 0.05) decreased by increasing dietary SID Lys levels. Fitted broken‐line (P < 0.05) and quadratic plot (P < 0.05) analysis of body weight loss indicated that the optimal SID Lys for primiparous sows was 0.85 and 1.01%, respectively. Average daily feed intake (ADFI), weaning‐to‐estrus interval and subsequent conception rate were not affected by dietary SID Lys levels. Increasing dietary lysine had no effect on litter performances. Protein content in milk was increased by dietary SID Lys (P < 0.05). Dietary SID Lys tended to increase concentrations of serum insulin‐like growth factor I (P = 0.066). These results of this experiment indicate that the optimal dietary SID Lys for lactating gilts was at least 0.85%, which approaches the recommendation of 0.84% that is estimated by the National Research Council (2012).     

Some descriptive characteristics of a new goat breed called Honamli in Turkey

This study has been carried out in the Western Mediterranean Region of Turkey on seven different Honamli goat flocks. The aim of this study was to determine the growth characters, survival rate (till weaning, 105th day), some reproductive characteristics and marketable milk yield. The data were collected from 516 does and 210 kids (125 buckling and 85 doelings). The results indicate that the numbers of multiple birth and litter size were 32.8 % and 1.35 respectively. Survival rates of kids at the 30th, 90th, and 105th days were 98.5, 97.2, and 97.2?%, respectively. The average birth weight for the buckling and doelings was 4.1 and 3.7?kg, respectively. The average weaning weights for buckling and doelings were 26.9 and 23.4?kg, respectively. The effects of dams?? age, on sex and birth type on the growth of Honamli kids were statistically significant (p?<?0.05, p?<?0.01, and p?<?0.001). While the diameters of erythrocytes of Honamli goats are smaller, the density of hemoglobin in the erythrocytes is more than Asian, Indian, and American caprine breeds. The average lactation length and marketable milk yield was assessed to be at 210.3?days and was 89?L, respectively. The growth characteristics of Honamli kids at weaning age were assessed to be higher than most of the other goat breeds in Turkey. The results further indicated that there is a significant variation in the production traits among the different Honamli goat flocks. Production traits of Honamli goats at different breeding conditions should further be investigated to come to a definite conclusion.     

Growth performance of Black Bengal,Saanen, and their crossbred F1 as affected by sex,litter size,and season of kidding

The objective of the present study was to determine the factors that influenced growth performance of the goat kids of Black Bengal (BB), Saanen (SA), and their crossbred F1 (male Bengal × female Saanen [BBSA] and male Saanen × female Black Bengal [SABB]). Data for 674 kids were analyzed from 316 litters and 134 does. All kids were weekly measured on their characteristics (body weight, length, height at the withers, and chest girth) from birth to 11 weeks old. The kid’s breed and sex, litter size, and season of kidding influenced birth weight and other characteristics through the experiment. The SA and BBSA kids showed similar performance, which were higher than BB and SABB kids. Male kids had higher performance than female kids, and kids from a single litter showed the highest performance. Kids born during rainy season showed lower performance than those born in hot and cool seasons. In conclusion, the crossbred BBSA is superior to SABB or BB to raise in tropical climate Moreover, sex, litter size, and kidding season also affected growth performance during the preweaning period up to 11 weeks old.     

Effects of genetic and environmental factors on pre-weaning and post-weaning growth in West African crossbred sheep

Effects of genetic and environmental factors on pre-weaning and post-weaning growth were studied in West African crossbred sheep. Effects of lamb genotype (7/8 Sahelian–1/8 Djallonké, 3/4 Sahelian–1/4 Djallonké and 1/2 Sahelian–1/2 Djallonké; hereafter denoted 7/8Sa, 3/4Sa and 1/2Sa, respectively), parity, type of birth, sex of lamb and year-season of lambing on birth weight, weaning weight, 8-month weight and pre- and post-weaning growth rates were determined. At birth 7/8Sa and 3/4Sa lambs were heavier (p<0.01) than 1/2Sa lambs. Lambs born to first-parity ewes were lighter (p<0.01) at birth than lambs of older ewes. At weaning and 8 months of age, lambs born to fourth-parity ewes were heavier (p<0.05) than those born to ewes of the other parities. Parity did not have any significant effects on pre-weaning growth rate. Lambs born in the rainy season of 2001 were significantly heavier at birth and at 8 months of age than those born in the dry season of 2001/02, but there was no difference between the two groups at weaning. Pre-weaning growth rate was significantly faster in lambs born in the dry season of 2001/02 but the reverse was true for post-weaning growth rate.     

Genetic and phenotypic parameter estimates for reproduction traits in indigenous Arsi-Bale goats

The study was conducted to evaluate reproductive performances and estimate genetic parameters for reproduction traits in Arsi-Bale goats. A total of 792 kidding records collected from 2001 to 2007 were used. Parity of dam, year, season and type of kidding were investigated as fixed effects by PROC GLM of SAS. Derivative-Free Restricted Maximum Likelihood (DFREML) method was used to estimate genetic parameters by fitting four animal models. Parity of dam and year of kidding influenced (P < 0.05) all the traits. The overall means for age at first kidding (AFK), kidding interval (KI), litter size at birth (LSB), litter size at weaning (LSW), litter weight at birth (LWB), litter weight at weaning (LWW), abortion and dystocia were 574.9 ± 8.3 days, 280.0 ± 13.7 days, 1.6 ± 0.03, 1.37 ± 0.03, 3.7 ± 0.08 kg, 9.11 ± 0.38 kg, 3.8% and 0.13%, respectively. The estimates of direct additive heritability for the traits, except for abortion and dystocia, under the best model (direct animal for AFK and repeatability model for other traits) were 0.245 ± 0.19, 0.060 ± 0.08, 0.074 ± 0.05, 0.006 ± 0.05, 0.125 ± 0.05, 0.053 ± 0.07, respectively, while the corresponding permanent environmental effects were 0.00 ± 0.00, 0.07 ± 0.07, 0.08 ± 0.05, 0.172 ± 0.06, 0.03 ± 0.04 and 0.07 ± 0.05, respectively. Repeatability estimates for KI, LSB, LSW, LWB and LWW were 0.13, 0.15, 0.18, 0.16 and 0.12, respectively. Genetic correlations between reproductive traits vary from medium to high. Arsi-Bale goats have good reproductive performance with low incidence of reproductive disorder. Except for AFK, other traits have low estimates of heritabilities with high genetic correlation among the traits. Repeated measures of the traits are needed before deciding to keep or cull the animal.     

Effect of doe milking and supplementation using <Emphasis Type="Italic">Dichrostachys cinerea</Emphasis> pods on kid and doe performance in grazing goats during the dry season

Effects of supplementation and milking of Matebele does four weeks pre-partum to weaning, on milk yield, kid birth weight and growth rate were studied. Forty does were divided into four treatments: supplemented and milked (SM), supplemented and not milked (SNM), not supplemented and milked (NSM); and not supplemented and not milked (NSNM). Supplemented goats were given 200 g/doe/day of Dichrostachys cinerea pods containing 19% CP. The study was carried out in September during time of feed unavailability and animals were grazed on rangelands for seven hours before being given the supplement. Fifty-six kids were born from all the experimental animals and 24 were singles whereas 32 were twins. Milk yield was higher (P < 0.05) in supplemented than non-supplemented does. Although supplementation had no effect on kid birth weights, growth rates were higher (P < 0.05) in the SNM group (103 ± 10.1 g/day) than in the SM group (74 ± 10.8 g/day). Among the non-supplemented groups, kids from milked does had higher (P < 0.05) daily gains (85 ± 10.9 g/day) than those from non-milked does (67 ± 10.7 g/day). Weaning weights were higher (P < 0.05) in SNM does (12.8 ± 1.30 g/day) than in the SM does (10.2 ± 1.17 g/day). Among kids from the non-supplemented does, those from milked does had superior (P < 0.05) weaning weights (11.2 ± 1.23 g/day) than those from non - milked does (9.2 ± 1.27 g/day). Mortalities were also lowest in kids born from SNM does. It is concluded that pre-partum to weaning supplementation generally increases milk production which then increases kids growth rates and weaning weights, as well as reduce kid mortalities.     

Environmental factors and interval from the introduction of rams to estrus in postpartum Saint Croix sheep

The objective of this study was to determine whether season and total rainfall during the breeding season, sheep parity, and/or litter size affect the interval from the introduction of rams to estrus (IRE) in hair Saint Croix sheep in northeastern Mexico. An analysis was made of 874 services performed during 9 years, introducing the rams into the sheep flock after an isolation period of 60 days during the postpartum period. Estrus was recorded twice daily during 35 days. Year and season influenced significantly on the interval between ram introduction and estrus length (P < 0.01). Winter IRE length (7.9 ± 0.1 days) was shorter than in the other three seasons (11.1 ± 0.2, 11.1 ± 0.1, and 16.2 ± 0.2 days in summer, autumn, and spring, respectively) (P < 0.01). An interaction was observed between rainfall and season, then by rainfall between 0 and 100 mm, IRE was shorter (P < 0.05) in winter (6.8 ± 0.3 days), and by rainfall between 100 and 199 mm, IRE was shorter (P < 0.05) in autumn (10.2 ± 0.5 days); however, when rainfall was beyond 200 mm, IRE length was shorter (P < 0.01) in summer (4.8 ± 0.5 days) than in autumn (14.5 ± 0.3 days). The IRE length was also longer in first lambing ewes (P < 0.05) and was not affected by litter size. In the present study, several factors, including the breeding season, rainfall and parity, directly influenced the interval between the male introduction and the onset of estrus by Saint Croix hair sheep.     

Guinea-pig productivity under traditional management

Results of a 12 month study of traditional guinea-pig production in the western highlands of Cameroon are reported. The mean age of guinea-pigs (Cavia porcellus L.) at first parturition, kidding interval and litter size at birth were 126.30±10.40 d, 64.8±1.70 d and 1.63±0.26 kids respectively. The annual reproductive rate was 9.18 kids/breeding doe while the doe post-partum weight was 530 g. Mean body weights at birth, presumed weaning (21 d) and 15 weeks of age were 78.36±3.20, 147.51±8.10 and 418.88±32 g respectively. Type of birth and sex had a significant effect on body weight at all ages. Birth weight dropped significantly from 83.88±2.87 g for singles to 81.57±3.40 g for twins, 74.25±2.39 g for triplets and 73.75±4.12 g for quadruplets. These differences were maintained to maturity (15 weeks). Males were generally heavier than females. Mortality rates were relatively high among kids: 24% at birth, 39% at 3 weeks and 40% at 15 weeks. Productivity indices were 0.827 kg of young weaned per doe per year, 1560 g of young weaned per kg of doe per year and 2.52 kg of young weaned per kg metabolic weight (kg^0.75) of female per year.