Factors affecting the reproductive performance of goats under intensive conditions in a hot arid environment

Goat flock abortion: a retrospective study at Abergelle Agricultural Research Center, Tigray, Ethiopia

BACKGROUND

Small ruminants are the principal component of livestock production in Tigray region, Ethiopia. But their productivity is affected by various factors. According to farmers and expert observation, goat abortion is among the leading causes of production losses in Tanqua-Abergelle district. However, study findings that examine the extent of distribution and economic impact of abortion cases in goats in the district are scarce. This retrospective study investigated the occurrence of abortion and its associated risk factors in three goat breed types at Abergelle Agricultural Research Center goat breeding site over a seven year period. The study included a total of does above one year old, and data were collected from a casebook that was specifically prepared for abortion cases. A thorough follow up was conducted to identify abortion cases. Additionally, a community survey was conducted in selected villages where the research center is located.

RESULTS

The overall abortion proportion was 29.8% in the goat farm. Begait goat breeds had the highest abortion proportion (50.9%, CI 0.36-0.64) in 2015/16. Multivariate logistic regression analysis identified year, season, age and breed as major risk factors of abortion occurrence at flock level. Accordingly, the likelihood of goats experiencing abortion during the dry season (proportion = 34) was 1.87 times higher compared to those in the wet season (proportion = 22.8). Begait breeds had a higher incidence of abortion (proportion 37.5%, OR 4.87, CI 2.49-10.35) compared to other breeds. Age was negatively associated with abortion, suggesting that older goats (OR = 0.67) had a higher relative risk than younger goats (OR = 0.57). Moreover, the study noted a high incidence of abortion during the years 2014/15 to 2016/17 (proportion = 35.7-39.7). Within-breed analysis revealed that age and season were significant risk factors for Abergelle and Begait breeds, respectively by using a multivariate logistic regression analysis. A community survey indicated that 89.7% households responded their goats experienced abortion.

CONCLUSIONS

This study highlighted the high prevalence of goat abortion at Abergelle and identifies important risk factors associated with its occurrence. The findings can inform targeted interventions to reduce abortion rates and improve goat productivity in the district.

The utilisation of domestic goats in rural and peri-urban areas of KwaZulu-Natal, South Africa

Goats are a common ruminant in livestock husbandry systems in communal areas of southern Africa, but less so in peri-urban areas. While dynamics of goat farming in the former are relatively well-understood, little is known about it in peri-urban environments. We investigated the contribution of small-scale farming of goats to household livelihoods in rural and peri-urban areas in KwaZulu-Natal Province of South Africa. We used a semi-structured questionnaire survey to elicit views of 115 respondents on the contribution of goats to household income at two rural (Kokstad, Msinga) and two peri-urban (Howick, Pietermaritzburg) locations. Goats contributed to household income as a source of cash and meat in various sociocultural contexts such as at weddings, funerals and festive period gatherings (e.g. Easter and Christmas), including payment for household needs and expenses including food, school fees and medico-cultural consultations. These findings were more pronounced in rural areas, where more goats were kept than in peri-urban areas, which also had smaller herds per household. Goats were a source of cash in numerous ways including sales of their skins after slaughter and use of skins through value addition to make household craft items such as stools that could be sold for cash. None of the farmers milked their goats. Goat famers also kept cattle (52%), sheep (23%) and chickens (67%). Goat ownership appeared to be more profitable in rural areas and contributed to a lesser extent as a source of income in peri-urban areas where goats were largely kept for sale. There is potential for increased value addition of goat products to increase returns from small-scale goat farming in rural and peri-urban settings. Artefacts and cultural symbols derived from goat products are pervasive amongst Zulu people, and represent an additional avenue of research into 'hidden' valuation of goats.

Effect of breed and management practices on reproductive and milking performance of rangeland goats

The traditional goat production systems on arid and semi-arid rangelands of northern Mexico are characterized by minimum external inputs; therefore, little is known about goat response to technological improvements. This observational study aimed to ascertain the effect of using improved goat production technologies and breed on milk yield and reproductive performance of goats on rangeland. The study was conducted from January 2017 to June 2018. Thirty-seven goat herds comprising 6393 animals were used. Goats supplemented with 250 g of concentrate (S-goats; 14% crude protein) 30 days before breeding produced significantly more daily milk yield (218 ± 61 vs. 200 ± 60 g) than the unsupplemented (UNS-goats) goats. Milk production per lactation was 12 percentage points greater in goats with access to plain salt throughout the year than those without salt access. The absence of deworming significantly depressed daily milk yield (189 ± 55 vs. 221 ± 61 for non-treated and treated goats). In 5 months, the lowest total milk yield was for Boer goats (26.9 ± 8.3 kg) and the highest for Nubian goats (36.1 ± 9.2 kg). The kidding rate was significantly higher in the S-goats than in the UNS-goats group (66.9 vs. 62.8%). Salt-supplemented goats had a significantly greater kidding rate than goats not receiving salt (68.5 vs. 61.2%). The lowest kidding rate was for Saanen goats and the highest for Nubian goats (66.2%). These findings indicate that milk yield and reproductive performance were primarily influenced by supplementing grazing goats with concentrates and salt in this semi-arid rangeland.

Estimation of genetic parameters for early reproduction traits in Beetal goat

The evaluation of early reproduction traits in Beetal goat was performed for possible effects of genetic and non-genetic factors on litter size at birth (LSB), litter size at weaning (LSW), litter weight at birth (LWB), litter weight at weaning (LWW) and age at first kidding (AFK). The data records consisted of information of pedigree and targeted traits pertained to 223 does born to 25 sires and 122 dams between the years 2004 to 2019. A general linear model was used for assessment of non-genetic factors such as period of birth, type of birth and dam's weight at kidding on studied traits. Genetic evaluation of targeted traits was done to estimate variance components and genetic parameters under dyadic mixed modelling. The estimates of least-square means for LSB, LSW, LWB, LWW and AFK were observed as 1.27 ± 0.03, 1.25 ± 0.03, 3.24 ± 0.07 kg, 13.08 ± 0.30 kg and 27.56 ± 0.58 months, respectively. Only the period of birth showed significant (P < 0.05) effects for targeted traits in this study. The estimates of direct heritability for LSB, LSW, LWB, LWW and AFK were low in magnitude as 0.08, 0.03, 0.10, 0.03 and 0.06, respectively. The moderate to high genetic and phenotypic correlations among litter traits indicate simultaneous improvement for these traits. It was concluded that low ranged direct heritability estimates for targeted traits indicated modest scope for genetic improvement of reproductive efficiency in Beetal goat through selection and, therefore, adoption of improved managerial practices is necessary to improve reproductive efficiency of Beetal goat.

Terminal Crossbreeding of Murciano-Granadina Goats to Boer Bucks: Effects on Reproductive Performance of Goats and Growth of Kids in Artificial Rearing

The aim of this work was to improve the growth characteristics of Murciano-Granadina (MG) kids through terminal crossbreeding of MG goats to Boer bucks. Four experiments were carried out, using a total of 354 MG goats, half of which were mated with MG bucks (n = 12) and the other half with Boer bucks (n = 12). The kids were raised in artificial rearing until slaughter weight (9 kg). The birth weight and average daily gain were recorded in crossed kids (n = 197 and 145, respectively) and purebred kids (n = 257 and 169, respectively). Crossed kids presented significant differences (p < 0.001) compared to MG purebred kids in birth weight (+ 24%), mortality in artificial rearing (-37%), average daily gain (+32%) and milk powder conversion rate (-16%). However, the reproductive performance rates of MG goats mated with Boer bucks were slightly worse (pregnancy rate: 78.5% vs. 86.6%, p < 0.05; kidding rate: 62.0% vs. 75.7%; p < 0.01; prolificacy: 1.9 vs. 2.1 kids/parturition), especially when the matings took place in non-breeding season (experiments conducted at latitude 38-39° N). It is concluded that the terminal crossbreeding of MG goats to Boer bucks (those not used to produce replacement kids) could be an interesting option for ethical goat production.

Towards objective measurement of reproductive performance of traditionally managed goat flocks in the drylands of Ethiopia

Reproductive performance is a key determinant for the efficiency of goat production. Regular monitoring of reproductive efficiency is essential to assess management and to avoid financial losses due to poor performance. To allow more objective measurement and comparisons over time, we propose a novel quantitative approach for defining annual reproductive performance by combining common performance indicators into a goat flock index. Commonly used reproductive performance measures were collected from 242 goat flocks in four districts in dryland of Ethiopia between July 2018 and February 2019. Principal component analysis (PCA) was performed to identify biologically meaningful latent components that explain annual reproductive output (ARO) and annual reproductive wastage (ARW). Together with the remaining annual reproductive performance measures, the ARO and ARW components were included in a PCA to derive an algorithm for a goat annual reproductive performance index (G-ARPI). One component representing variation in kidding interval, PC_ARO1 and PC_ARW1 was extracted and normalized to a 10-scale value. The flocks were classified into good performing (15.63%) with index > 8.5, moderately performing (48.21%) with index values ranging from 6.5 to 8.5 and poor performing (36.16%) with index < 6.5. Good performing flocks have higher scores for reproductive output measures, lower scores for reproductive wastage and lower kidding interval. The proposed G-ARPI can be used as an objective tool to compare reproductive performance between management systems, evaluate the costs of poor reproductive management and will be useful for economic models that aim to identify the most cost-efficient intervention option and monitor the impact of interventions. We present here the index for goat production in dryland systems in Ethiopia; the approach can easily be adapted to other production systems elsewhere.

Causes and Flock Level Risk Factors of Sheep and Goat Abortion in Three Agroecology Zones in Ethiopia

A cross-sectional survey was conducted to estimate the incidence of small ruminant abortion and identify its major causes and potential risk factors in goat and sheep flocks in three agroecology and production systems of Ethiopia. Information on pregnancy outcomes and management risk factors were collected for 299 goat and 242 sheep flocks. Blood samples were collected from 133 sheep and 90 goat flocks and tested for Coxiella burnetii, Brucella spp., Chlamydia abortus, and Toxoplasma gondii. A causal diagram outlined relationships between potential predictor variables and abortion in the flock. The effect of management and exposure to infectious causes on the number of abortions in the flock across agroecology was tested using zero-inflated negative binomial regression. Results showed that 142 (58.68%) goats and 53 (17.73%) sheep flocks reported abortions in the 12 months before the survey. The mean annual flock abortion percentages were 16.1% (±26.23) for does and 12.6% (±23.5) for ewes. Farmers perceived infectious diseases, extreme weather conditions, feed shortage, physical traumas, and plant poisoning as the most important causes of abortion. A higher proportion of abortion was recorded during the short rainy season (March to May) and start of the short dry and cold season (June to August) in the lowland mixed crop-livestock and pastoral agroecology and production system, respectively. Overall, 65.41% sheep and 92.22% goat flocks tested positive for one or more abortion causing agents, namely, C. burnetti, C. abortus, Brucella spp., and T. gondii; mixed infection was found in 31.58% sheep and 63.33% goat flocks. Spending the night in a traditional house and providing supplementary feed for pregnant dams were important management factors which significantly (p ≤ 0.05) decreased the risk of abortion by 2.63 and 4.55 times, respectively. However, the presence of other livestock species and dogs in the household and exposure of the flock to Brucella spp. or anyone of the four tested infectious agents significantly (p ≤ 0.05) increased the risk of abortion in sheep and goat flocks. In general, abortion is a challenge for small ruminant production in the study area especially in lowland agroecology and calls for improvement in husbandry practices, health care and biosecurity practices.

Abortion and various associated risk factors in dairy cow and sheep in Ili, China

We studied livestock abortion and various associated risk factors in the Ili region of northwest China. Livestock abortion prevalence was estimated and correlated with infections (Brucellosis, Salmonellosis, Mycoplasma and Chlamydia seropositivity) and management (farming type and contact with other herds/flocks) risk factors. A total of 2996 serum samples (1406 cow, 1590 sheep) were identified by RBPT (Rose Bengal Plate Test) and c-ELISA (competitive-enzyme linked immunosorbent assay), and they showed the overall seroprevalence of brucellosis in the study area was cow 6.76%, sheep 9.50%. The seroprevalence of brucellosis in X county was cow 7.06%, sheep 9.12%; in H county was cow 11.70%, sheep 10.80%; and in Q county was cow 4.22%, sheep 9.11%. The overall seroprevalence of Mycoplasma in the study area was cow 3.20%, sheep 6.42%. The seroprevalence of Mycoplasma in X county was cow 3.39%, sheep 7.98%; in H county was cow 5.26%, sheep 9.97%; and in Q county was cow 2.11%, sheep 4.33%. The Odds ratio of brucellosis for cow and sheep, respectively, were 45.909 [95% CI 26.912-78.317, P<0.001] and 70.507 [95% CI 43.783-113.544, P<0.001] times higher than other abortion-related factors including mixed farming, contact with other flocks and Mycoplasma infection. A total of 54 samples, including aborted cow (22), sheep (30) fetuses and milk samples (2), were identified as Brucella melitensis (B. melitensis) positive. A total of 38 Brucella were isolated from 16 aborted cow, 20 sheep fetuses and 2 milk samples. All of these isolates were identified, and confirmed, as B. melitensis. A phylogenetic tree showed that the Brucella isolates closely matched the B. melitensis biovar 3 isolated in Inner Mongolia, China, and B. melitensis isolated from Norway and India. These results suggest that B. melitensis biovar 3 is the main pathogen responsible for cow and sheep abortion and also pose a human health risk. Additionally, livestock reproduction can also be influenced by Mycoplasma infection and managerial factors (farming type and contact with other herds/flocks), especially in remote areas.

Reproductive performance in goats and causes of perinatal mortality: a review

Goat meat production is an expanding industry in Australia. However, there is limited data quantifying the levels of reproductive performance, particularly under extensively grazed rangeland conditions, which would inform interventions to improve performance. This review aimed to quantify the levels of reproduction, time and causes of reproductive wastage in goats. It considers the levels of fertility, fecundity, embryonic loss, fetal loss and post-natal survival reported under Australian conditions, and comparisons are made with international reports. Key management factors that may contribute to reproductive performance include breed, seasonality, nutritional conditions, and weather conditions at kidding. While goats are potentially prolific breeders, in Australia, the variation in weaning rate (kids/doe joined) among properties is large (51–165%), although the causes of this variation are not well defined. Generally, conception and kidding rates are high, although fetal loss associated with undernutrition is more likely in goats than sheep. As with sheep, perinatal losses are generally the largest source of wastage, with an average 20% kid mortality, but this level is influenced by litter size and appears to be higher under extensive rangeland systems. The causes of perinatal kid loss under Australian conditions are similar to those in sheep, with starvation–mismothering–exposure and dystocia or stillbirth the key causes. Studies are needed to accurately quantify the level and causes of reproductive wastage in commercial herds, including a range of management situations, to enable effective interventions to be developed.

The Effects of Reproductive Disorders, Parity, and Litter Size on Milk Yield of Serrana Goats

Several reproductive factors may affect milk yield in goats. The main aim of this study was to evaluate the influence of reproductive disorders, parity, and litter size, and their interactions on the 150-day standardized milk yield (SMY150) of low-producing dairy goats extensively raised. A total of 148,084 lactations between 1993 and 2015 were obtained from data of the Genpro pedigree records of the Transmontano ecotype of Serrana goat breed. The presence or absence of reproductive disorders (RD) from late (>half) pregnancy (abortions followed by lactation) or at kidding, number of fetuses (single vs. multiple), and parity (primiparous vs. multiparous) of the Transmontano ecotype of Serrana goat were used as fixed effects to fit a general linear model for a SMY150 output. A significant effect (p < 0.001) of all factors on SMY150, as well as three-way interactions, were observed. The SMY150 reduction subsequent to RD was 3.7% for multiparous and 9.6% for primiparous goats carrying singletons, and 14.1% for multiparous and 18.8% primiparous goats carrying multiple fetuses. It was concluded that a new lactation following abortion occurrence is viable for production purpose in low-producing dairy goats under pastoralism. Nevertheless, the impact of RD on SMY150 varied according to the number of fetuses and the parity of the Transmontano ecotype of Serrana goats. This information should be used in decision-making practices regarding reproductive and herd health management.

Genetic and phenotypic aspects of early reproductive performance in Raeini Cashmere goats

This study used pedigree information and data collected from 1979 to 2012 at the Raeini Cashmere goat breeding station, located in Baft City in Kerman Province in southeastern Iran. Genetic and phenotypic parameters for early reproductive traits of breeding does, including total numbers of kids born at first kidding (LSB1), total numbers of kids weaned at first kidding (LSW1), total birth weight of all kids born at first kidding (LWB1), total weaning weight of all kids weaned at first kidding (LWW1), and age at first kidding (AFK), were estimated using a Bayesian approach via Gibbs sampling. Posterior means for heritability estimates of LSB1, LSW1, LWB1, LWW1, and AFK were statistically significant, with values of 0.12, 0.23, 0.17, 0.15, and 0.46, respectively. Low-to-moderate additive genetic variation was present for the studied reproductive traits. Estimated genetic correlations among LSB1, LSW1, LWB1, and LWW1 were statistically significant and ranged from 0.12 between LWB1 and LWW1 to 0.72 between LSB1 and LSW1. Corresponding phenotypic correlation estimates were also statistically significant and ranged from 0.04 between LWB1 and LWW1 to 0.55 between LSB1 and LSW1. Posterior means of genetic and phenotypic correlations between AFK and other studied traits were statistically significant only for LSB1 and LWB1. For LSB1, LSW1, LWB1, and LWW1, we conclude that genetic and phenotypic improvement in any of these traits in Raeini Cashmere does would favorably influence all of the other traits. However, does that first kidded at younger ages have smaller litters at birth and lower litter birth weights at their first parity.

Temperature and rainfall are related to fertility rate after spring artificial insemination in small ruminants

A total number of 1092 artificial inseminations (AIs) performed from March to May were documented over four consecutive years on 10 Payoya goat farms (36° N) and 19,392 AIs on 102 Rasa Aragonesa sheep farms (41° N) over 10 years. Mean, maximum, and minimum ambient temperatures, mean relative humidity, mean solar radiation, and total rainfall on each insemination day were recorded. Overall, fertility rates were 58 % in goats and 45 % in sheep. The fertility rates of the highest and lowest deciles of each of the meteorological variables indicated that temperature and rainfall had a significant effect on fertility in goats. Specifically, inseminations that were performed when mean (68 %), maximum (68 %), and minimum (66 %) temperatures were in the highest decile, and rainfall was in the lowest decile (59 %), had a significantly (P < 0.0001) higher proportion of does that became pregnant than did the ewes in the lowest decile (56, 54, 58, and 49 %, respectively). In sheep, the fertility rates of the highest decile of mean (62 %), maximum (62 %), and minimum (52 %) temperature, RH (52 %), THI (53 %), and rainfall (45 %) were significantly higher (P < 0.0001) than were the fertility rates among ewes in the lowest decile (46, 45, 45, 45, 46, and 43 %, respectively). In conclusion, weather was related to fertility in small ruminants after AI in spring. It remains to be determined whether scheduling the dates of insemination based on forecasted temperatures can improve the success of AI in goats and sheep.

Management and meteorological factors affect fertility after artificial insemination in Murciano-Granadina goats

Over 6 years, 2004 artificial inseminations (AI) were documented from 13 goat farms. We quantified the effect on fertility rate of management factors (farm, year, month, timing and order of insemination, dose of progestagen, prostaglandin, equine chorionic gonadotrophin and prostaglandin doses, age, technician, problems at AI, body condition and buck) and meteorological conditions at AI (mean, maximum and minimum temperatures, mean relative humidity, mean solar radiation, and total rainfall). Meteorological variables were converted to categorical variables to quartiles and deciles. Overall fertility was 56%. Each of the management factors had a significant (P < 0.05) effect on fertility. Non-pregnant goats differed significantly in most of the meteorological variables. Successful inseminations were associated with significantly (P < 0.001) higher mean, maximum and minimum temperatures, and solar radiation, and lower relative humidity, and rainfall, than were failed inseminations. Fertility rates of the highest and lowest deciles were significantly different for each of the meteorological variables. Inseminations performed when meteorological values were in the highest decile of mean (62%), maximum (61%) and minimum temperature (60%), and solar radiation (59%), and the lowest of relative humidity (61%) and rainfall (57%) had a significantly (P < 0.0001) higher proportion of does that became pregnant than when meteorological values were within the opposite decile (47%; 34%; 55%; 46%; 45%, and 43%, respectively). In conclusion, management and meteorological factors affected the success of AI in goats. Although technical factors can be controlled, it remains to be determined whether scheduling the dates of insemination based on forecasted temperatures can improve the success of AI.

Abortion and various associated risk factors in small ruminants in Algeria

Identification of the causes of abortion among the huge population of small ruminants in Algeria (≈31 millions heads), is an important task for the control of livestock productivity and viability scourges to the small ruminants industry. Optimal production and utilization is constrained by a number of factors: disease, poor feeding and low management skills. Therefore, in the present study the prevalence of abortion in Algerian small ruminant's flocks was estimated and its possible association was correlated with infectious (PPR, BT and Brucellosis seropositivity) and managerial (flock size, grazing system, type of farming, and contact with other flocks) risk factors. The present study showed an overall flock prevalence of small ruminant's abortion as 75.33% (113/150) [95% CI 71.72-78.94%]. The risk factor analysis using multivariable logistic regression recognized the north-western and the steppe region as well as PPR positivity as a risk factor for abortion in Algerian small ruminant's flocks. The odds of flock abortion was 11.47 [95% CI 2.39-54.88; P=0.002] and 10.31 [95% CI 1.28-82.88; P=0.028] times higher in north-western and steppe regions respectively compared to other region. Also the presence of PPRV infection in small ruminant flocks amplified the odds by 6 times [95% CI 2.221-17.427; P=0.001].Surprisingly, the univariate analysis for the other risk factors associated with abortions in Algerian small ruminant flocks indicated no statistically significant links with bluetongue (P=1.000) and brucellosis seropositivity (P=0.334). Flock size (P=0.574), type of farming (P=0.443), grazing system (P=0.117) and contact with other flocks (P=0.245) was also not statistically significant. Our results revealed that abortion in small ruminants is a challenge to farmers and PPR was chiefly linked to it. Therefore an effective vaccination and control programme is advocated for small ruminants in Algeria.

Artificial insemination in Payoya goats: factors affecting fertility

The present study was conducted to determine the effect of different factors on pregnancy rate after artificial insemination (AI) with refrigerated and frozen semen in Payoya goats reared under commercial farm conditions. A total of 820 goats, belonging to 10 farms, was used. The total number of studied inseminations was 1384 over a 4-year period. Factors considered in the study were year, farm, month of AI, age of the goat at AI, dose of progestagen, eCG dose, buck, type of semen (refrigerated or frozen), technician, number of goats to be inseminated (group size), incidences at AI (problems, no problems, trans-cervical insemination), distance from semen collection to farm, number of previous kidding, kidding–AI interval, and milk production. The variable studied was fertility, expressed as successful kidding. Mean fertility was 59%. Six (farm, age, group size, transcervical AI, number of kidding and milk production) of the 15 factors studied presented a significant (P < 0.05) effect on fertility after AI. Our results demonstrated that it is difficult to control all the critical aspects of AI programs at the farm level. These factors should be controlled and the variations that could compromise the chance of being pregnant must be known by technicians. The good fertility results obtained during the non-breeding season emphasise the implementation of this technique so as to improve the competitiveness of the dairy Payoya breed flocks.

Some risk factors for reproductive failures and contribution of Toxoplasma gondii infection in sheep and goats of Central Ethiopia: a cross-sectional study

Reproductive failure has a negative impact on animal production, health and welfare and ultimately rural economies. In Ethiopia, the factors affecting small ruminant reproductive efficiency are inadequately investigated. A cross-sectional survey was done from November, 2010 to May, 2011 to investigate risk factors of reproductive failures including Toxoplasma gondii infection. Analysis of 1372 sera (787 sheep and 585 goats) from 409 flocks using ELISA showed high flock (59.7%) and animal (31.8%) level T. gondii seroprevalence. An overall 24.9% (341/1372) annual abortion rate (19.6% in sheep and 32.0% in goats) was recorded. Animal level T. gondii seroprevalence was significantly associated with abortion in Ambo and Ada'a-Liben districts (Odds ratio [OR] = 2.31, 95% confidence interval [CI]: 1.42, 3.76; P = 0.001). Questionnaire survey on 199 households of Ambo, Ada'a-Liben and Fentale districts revealed high flock level abortion (57.5%), still birth (28.9%) and neonatal losses (47.9%), which are significantly different between study districts (P<0.001). Multivariable logistic regression model showed that species (goat), large flock size, pastoral and agro-pastoral production systems, drinking water from river and stagnant water bodies, grazing/browsing in plain land and extensive management were significant predictors of flock level reproductive failures. In the final Zero inflated Poisson regression model number of abortions was significantly higher in goat than in sheep flocks (Incidence risk ratio [IRR] = 1.42, 95% CI: 1.08, 1.87; P = 0.012). It is also significantly higher in pastoral (IRR = 1.81, 95% CI: 1.16, 2.83; P = 0.008) and agro-pastoral production systems (IRR = 1.94, 95% CI: 1.32, 2.86; P = 0.001) than in sedentary production system. Prevention of toxoplasmosis, improved husbandry practices and further epidemiological studies to identify causes of reproductive failures are recommended.

Effect of feed restriction and realimentation with monensin supplementation on placental structure and ultrastructure in anglo-nubian goats

The aim of this study was to evaluate the effect of feed restriction followed by a realimentation with monensin supplementation on morphological, ultrastructural, and apoptotic characteristics in the term placenta of Anglo-Nubian does. Treatments were a control group (C = 5), a group fed at 0.70 of that consumed by controls (R = 7), and the same as R with monensin (M = 7). After parturition, 27 placentas were gathered, C: 7, M: 10, and R: 10. No differences were detected between treatments in relation to morphological and ultrastructural analysis. The greatest values of binucleate cells were detected in placentas from R, and it could be due to the need to compensate and satisfy nutritional differences of restriction. We detected the highest apoptotic index in R as a consequence of nutritional treatment. We describe for the first time the structural and ultrastructural morphology and remodeling by apoptosis of Anglo-Nubian placenta at term of goats subjected to nutritional restriction during peripubertal period and the use of monensin as a growth promoter.

Breed and experience effect on the sexual behaviors of Damascus and Egyptian-Nubian goat bucks

This study compares the sexual behaviors of bucks from two pure breeds of goats, Damascus and Egyptian-Nubian (Zaraibi), and assesses their relationships with the pregnancy and kidding rates of their inseminated does. Twenty-three bucks (12 Damascus and 11 Egyptian-Nubian bucks) were used in this study. These bucks were either in their first season of service (N =12, with an average age of 1.51 years) or had been previously used in service for several seasons (N = 11, with an average age of 3.34 years). Buck service behaviors toward estrous does were continuously recorded for 30 minutes from the moment of appearance of the doe. Egyptian-Nubian bucks were highly sexually active with estrous does in comparison with Damascus bucks. They required less time to mount and ejaculate for the first (P < 0.04) and second times (P < 0.0002) and tended to sniff, nudge and vocalize more frequently than Damascus bucks. In addition, Egyptian-Nubian bucks had more ejaculations and a higher mating efficiency (27.48% vs. 10.21%, P < 0.001), and their inseminated does had a higher pregnancy rate and larger litter sizes. Regarding the effect of experience, the data revealed a limited influence. No significant differences in sexual behavior were recorded between younger and older bucks. Conversely, pregnancy, kidding rates, and litter size were not influenced by the total number of ejaculations. From these results, it can be concluded that there were sexual behavior differences as a function of breed between Damascus and Egyptian-Nubian bucks and that experience had little impact in this study.

Development and application of a crossbreeding simulation model for goat production systems in tropical regions

A deterministic simulation model was developed to estimate biological production efficiency and to evaluate goat crossbreeding systems under tropical conditions. The model involves 5 production systems: pure indigenous, first filial generations (F1), backcross (BC), composite breeds of F1 (CMP(F1)), and BC (CMP(BC)). The model first simulates growth, reproduction, lactation, and energy intakes of a doe and a kid on a 1-d time step at the individual level and thereafter the outputs are integrated into the herd dynamics program. The ability of the model to simulate individual performances was tested under a base situation. The simulation results represented daily BW changes, ME requirements, and milk yield and the estimates were within the range of published data. Two conventional goat production scenarios (an intensive milk production scenario and an integrated goat and oil palm production scenario) in Malaysia were examined. The simulation results of the intensive milk production scenario showed the greater production efficiency of the CMP(BC) and CMP(F1) systems and decreased production efficiency of the F1 and BC systems. The results of the integrated goat and oil palm production scenario showed that the production efficiency and stocking rate were greater for the indigenous goats than for the crossbreeding systems.

Influence of sexually inactive bucks subjected to long photoperiod or testosterone on the induction of estrus in anovulatory goats

The objective of this study was to evaluate the efficacy of treating sexually inactive bucks with artificial long photoperiod or testosterone on the induction of estrus in anovulatory grazing goats. A total of 91 multiparous mixed-breed anestrous goats were randomly assigned to one of three treatment groups: (1) joining with bucks subjected to 2.5 month of artificial long days (16 h of light/day; n=31), (2) joining with testosterone-treated bucks (n=30), and (3) joining with untreated bucks (control; n=30). There were no differences between the light-treated (100%) and testosterone-treated (93%) bucks in their ability to induce estrus in anovulatory does. On the other hand, none of the goats in contact with control bucks exhibited estrus. The interval from start of mating to estrus was shorter in goats with the light-treated bucks (37.9 ± 4.8 h) compared with does in contact with testosterone-treated bucks (58.3 ± 8.7 h). The overall pregnancy rate in goats joined with light-treated, testosterone-treated and control bucks was 84%, 77% and 0%, respectively, with no difference (P>0.05) between the first two groups. Anogenital sniffing, approaches, mounting attempts, and mounts were highest (P<0.01) in light-treated bucks and lowest in control bucks. It was concluded that testosterone-treated bucks and long-day-treated bucks were equally effective in synchronizing estrus in anovulatory goats and resulted in similar levels of fertility. Given that light-treated bucks are unviable in communal production systems of goats raised by resource-poor farmers, the sexual arousal of bucks with testosterone is a practical and reliable method to induce ovulation in anovulatory goats in pastoral goat systems in hot environments.

Relationship between litter birthweight and litter size in five goat genotypes

The aim of the present study was to use a non-linear regression approach to investigate the relationship between litter birthweight and litter size of five breeds of goat under intensive conditions in a hot arid environment. Litter-size and litter-weight data on 20 117 kids from 13 685 litters representing five breeds, namely Saanen, Toggenburg, French Alpine, Anglo-Nubian and Granadina, were compared to evaluate this relationship. Regardless of breed, birthweight for kids born as twins, triplets and quadruplets was, on average, 92%, 87% and 83%, respectively, of that of singleton kids; litter size accounted for 81% of the variation in litter weight. The coefficient of the power regression differed (P < 0.01) among breeds, with similar slopes for French Alpine, Toggenburg and Saanen goats and a smaller litter-weight increase for every additional fetus in Anglo-Nubian and Granadina goats than in other breeds of goat. These results support the hypothesis that, regardless of parity, litter weight in dairy and Granadina goats increases at a reduced rate with increases in litter size, although the rate of change with the increasing number of fetuses was moderate, as indicated by a power regression of the form y = axb between these variables across age categories and breeds of goat.

Reproductive performance of Matou goat under sub-tropical monsoonal climate of Central China

The aim of the current study was to estimate reproductive parameters of Matou goat to evaluate a meat breed. Data on 2,560 kids from 1,197 kidding records of 638 does and on puberty of 546 females kids were collected from farmer household herds of Matou goats in six counties of Shiye city under Hubei Province in China. Statistical analyses on puberty, estrus, gestation length (GL), litter size (LS) and survival rate (SR) of kids at puberty were performed with software Genstat 5 (Release 3.1) by using descriptive statistics and regression models. The results showed that age at puberty of female kids was 108.4+/-19.1 days while estrus duration and cycle averaged 58.6+/-15.9 hours and 19.7+/-1.5 days respectively. Gestation length (GL) and litter size (LS) averaged 150+/-7.4 days and 2.14+/-0.9 respectively with 90.8% of survival rate (SR) of kids. GL was unassociated with parity, but delayed as LS increased. SR of kids at birth differed remarkably among parity 1 to 5, decreased significantly at parity 6 to 7, and then increased at 8th parity. In Matou goat over all twinning and triplet percentage was 45.4 percent and 16.3 percent whereas percentage of single birth was 27.4 percent. As twins and triplets birth rate is considerably higher in Matou goat so, this breed can be recommended to other parts of China and the world having similar climatic conditions.

The relationship between linear type traits and fertility traits in high-yielding dairy goats

Reproductive data collected from 13 medium-size goat farms in central Mexico (582 goats), were used to investigate if linear type traits influenced reproductive performance of high-yielding dairy goats. Data were analysed using multiple stepwise forward logistic regressions. Goats with the higher scores for strength were 1.43 times more likely (p < 0.05) to have larger litters (1.49 vs 1.39) than goats with lower strength. Goats approaching level rump angles were 1.68 times more likely (p < 0.01) to have larger litters, compared with goats with extremely sloped rump angles (1.48 vs 1.37). Goats with rear legs nearly straight (posty) in hock tended (p < 0.08) to presented larger litters than goats with rear legs slightly angled (sickled) in hock (1.49 vs 1.38). Less pronounced rump angle was favourable associated (p < 0.05) with litter weight (4.88 vs 4.53 kg) compared with goats with low pin bones. Goats with poorer udder texture were 1.42 more likely (p < 0.05) to have heavier litters than goats with good udder texture. Goats with faulty mammary system tended (p < 0.07) to have heavier litters than goats with good mammary system. Increasing udder height was associated (p < 0.05) with increasing number of services per conception. Goats with good fore udder attachment and non-refined heads were at reduced risk (p < 0.05) for stillbirths. Goats with stronger median ligament were 65% less likely (p < 0.05) to lose their foetuses than those with looser udder support. Our findings indicate that a greater litter size and litter weight is expected in goats as rump angle becomes less sloped. This study showed that a relationship exists between strength of goats and litter size, and that some traits linked to high milk yield were antagonist to some reproductive traits.