Milk production and lactation length in Ankole cattle and Ankole crossbreds in Rwanda

This study assessed daily milk yield (DMY), 100-day (MY100), and 305-day (MY305) milk yield, and lactation length (LL) in purebred Ankole cattle and Ankole crossbreds, and the influence of environmental factors on these traits. Milk yield data were obtained for 865 cows and 1234 lactations and analyzed using a mixed linear model. The overall least squares mean of DMY, MY100, and MY305 across breed groups was 2.7 L (N = 1234, SD = 1.7), 262 L (N = 959, SD = 176), and 759 L (N = 448, SD = 439), respectively, while the average lactation length was 256 days (N = 960, SD = 122). All factors included (breed group, season and year of calving, and parity) were significant for yield traits, except season of calving for MY305. First-parity cows had the lowest milk production, and fourth-parity cows the highest. For all traits, pure Ankole cows had the lowest milk yield. Among the crossbreds, there was no significant difference between Ankole × Friesian, Ankole-Jersey mother × Sahiwal sire, and Ankole-Sahiwal mother × Jersey sire, or between Ankole × Sahiwal and Ankole-Sahiwal mother × Sahiwal sire. It was concluded that Ankole crosses with Friesian or Jersey can be beneficial, even under a management system of limited nutrition as in Rwanda.

     

Exposure of Ankole and crossbred cattle to theileriosis in Rwanda

Summary Susceptible Ankole (Sanga:Bos indicus/Bos taurus) and crossbred Ankole x Jersey (B. taurus) and Ankole x Sahiwal (B. indicus) cattle derived from a farm in Rwanda with no recent history of theileriosis, were infected withTheileria parva stocks from Rwanda either by feeding infectedRhipicephalus appendiculatus ticks on the ears, inoculation of tick derived stabilate or natural exposure to tick challenge. The Ankole cattle originated from local stock born and bred in East Coast fever (ECF) endemic areas of Rwanda. Disease, followed by spontaneous recovery, was observed in 49 of the 72 Ankole cattle after infection withT. parva (68%); the other 23 animals (32%) died of ECF. In contrast 21 of the 33 infected crossbred cattle (64%) died of ECF. It is concluded that the partialTheileria tolerance of the Ankole is, to a great extent, genetic. The basis of this partial tolerance seems to be their ability to limit the explosive multiplication of macroschizonts during the acute phase of the disease.

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Resumen Se infectó ganado Ankole susceptible (Sanga:Bos indicus/Bos taurus) y ganado cruzado Ankole x Jersey (Bos taurus) y Ankole x Sahiwal (Bos indicus) proveniente de una finca en Rwanda sin historia reciente de theileriosis, conTheileria parva procedente de Rwanda, mediante la adhesión en la oreja deRhipicephalus appendiculatus infectado, inoculación de estabilados derivados de garrapatas, o exposición natural a la enfermedad a través del vector. El ganado Ankole era originario de un área endémica de theileriosis en Rwanda. Se observó la enfermedad seguida de recuperación, en 49 de 72 animales Ankole infectados conT. parva (68%); los otros 23 animales murieron (32%). En contraste, 21 de los 33 animales cruzados infectados (64%), murieron. Se concluye, que la tolerancia parcial del ganado Ankole es de origen genético. Las bases de ésta tolerancia genética, parece debida a la habilidad para limitar en cierto modo la multiplicación explosiva de macroesquizontes, durante la fase aguda de la enfermedad.

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Résumé On a infecté du bétail sensible, de race Ankolé (Sanga:Bos indicus/Bos taurus) et des croisés Ankolé x Jersey (B. taurus) et Ankolé x Sahiwal (B. indicus), provenant d'une ferme au Rwanda sans cas récents de theilériose, avec des souches deTheileria parva du Rwanda, par l'application de tiques (Rhipicephalus appendiculatus) infectées sur les oreilles, par inoculation de stabilat de tiques infectées ou par l'exposition à un challenge naturel de tiques. La souche d'Ankolé était originaire du cheptel local Rwandais, né et élevé dans les régions où la theilériose est endémique. La maladie suivie par la guérison spontanée fut observée dans 49 des 72 Ankolés (68%), les autres 23 animaux (32%) ont succombé à la theilériose. Par contre 21 des 33 croisées infectées (64%) ont succombé à la theilériose. Nous concluons que la tolérance partielle des Ankolés contre la theilériose, est génétique. La base de cette tolérance semble être leur capacité de limiter la multiplication explosive des macroschizonts pendant la phase aigu de la maladie.

     

Comparison of production systems and selection criteria of Ankole cattle by breeders in Burundi, Rwanda, Tanzania and Uganda

A survey in Burundi, Rwanda, Tanzania and Uganda was conducted in order to determine the different production systems under which Ankole cattle are currently kept. Additionally, selection criteria of livestock keepers were documented. In Burundi, Rwanda and parts of Uganda, livestock keepers are sedentary and herds are small, whereas in the other areas Ankole cattle are kept in large herds, some of them still under a (semi-)nomadic system. Milk is the main product in all areas, and is partly for home consumption and partly for sale. Although the production systems vary in many aspects, the selection criteria for cows are similar. Productive traits such as milk yield, fertility and body size were ranked highly. For bulls, the trait ‘growth’ was ranked highly in all study areas. Phenotypic features (coat colour, horn shape and size) and ancestral information are more important in bulls than in cows. The only adaptive trait mentioned by livestock keepers was disease resistance. In areas of land scarcity (Burundi, Rwanda, western Uganda), a clear trend from pure Ankole cattle towards cross-bred animals can be observed.     

Outbreak of wildebeest-associated malignant catarrhal fever in Ankole cattle

During an outbreak of malignant catarrhal fever in a herd of Ankole cattle in a zoological collection, two adult cows and one adult bull from a herd of 15 died or were euthanased between July and November 2004. The clinical, gross postmortem and histological findings were typical of the disease in uk native domestic cattle. The diagnosis was confirmed by serology in two animals, and by pcr in all three; the pcr provided evidence of alcelaphine herpesvirus type 1 infection in all three animals and also of ovine herpesvirus type 2 infection in one.     

延边黄牛二元轮回杂交育肥效果研究

选用西门塔尔、夏洛来、利木赞和安格斯与廷边牛的F_1代母牛与其父本再次杂交进行育肥效果比较试验。结果表明：夏洛来改良牛的屠宰率高于其它三组改良牛,且组间差异显著(P＜0．05),其它三组无显著性差异(P＞0．05)。牛肉的品质方面,四组改良牛在眼肌面积、嫩度、pH值、灰分上均无显著性差异(P＞0．05);利木赞改良牛的蛋白质含量显著高于其它三组改良牛(P＜0．05),西门塔尔组牛、夏洛来组牛、安格斯组牛间差异不显著;在脂肪含量上四组改良牛间差异显著(P＜0．05),且利木赞改良牛低于其它三组改良牛。     

Reproductive performance in crosses of Angus, Santa Gertrudis and Gelbvieh beef cattle

Angus (A), Santa Gertrudis (S), and Gelbvieh (G) sires were mated to A and S dams to produce five mating types (A X A, S X S, S X A, A X S and G X A) in each of four calf crops. The study involved 501 matings. Overall means for the traits measured (calves born/cows exposed, Julian birthdate, calving ease, percentage of live calves at 24 h, birth weight, survival to weaning and gestation length) were 74.2%, 48.8 d, 96.4%, 33.2 kg, 95.4% and 283.8 d, respectively. Angus dams had a 14 percentage point (P less than .05) advantage over S dams for percentage of calves born/cows exposed. The effect of heterosis in crosses of A and S for percentage of calves born/cows exposed was negative (-11.1%) and approached significance. The percentage of calves born/cows exposed were 84.4, 70.4, 76.1 and 62.3 for the A X A, S X S, S X A and A X S mating types, respectively. Matings involving A sires and dams produced calves significantly earlier in the calving season than did matings involving S sires and dams. Matings involving S sires and dams produced calves with significantly longer gestation periods than matings of A sires and dams. Calving ease score and survival to weaning were not affected by breed of sire, breed of dam, age of dam, sex of calf, or the interaction of breed of sire X breed of dam. Percentage of live calves at 24 h indicated that straightbred S calves were significantly less viable at birth than the other four mating types.(ABSTRACT TRUNCATED AT 250 WORDS)     

Reproductive physiology in Zebu cattle. Unique reproductive aspects that affect their performance

This article describes the reproductive physiology of Zebu cattle and specific strategies that, when used in concert with an understanding of the physiologic differences between Zebu and other cattle, can improve reproductive performance.     

荷斯坦杂种牛生长性能遗传改良效果评估

为了评估验证荷斯坦种公牛对荷斯坦杂种牛生长性能的遗传改良效果,以荷黄低代杂种、荷黄高代杂种和纯种荷斯坦牛3种群体共计293头奶牛为研究材料,利用北美荷斯坦种公牛对不同奶牛群体进行杂交改良,根据系谱信息追踪各群体的后裔,测定个体初生、2月龄、6月龄、12月龄、14月龄和成年体重,以纯种荷斯坦牛为对照组,用最小二乘法分析群体、世代和母本与生长性能的相关性,评估杂种奶牛生长性能的遗传改良效果。结果表明:高代杂种和低代杂种的初生重显著低于纯种(P0.05);高代杂种和纯种12月龄重、14月龄重、成年体重显著高于低代杂种(P0.05),高代杂种与纯种之间差异不显著(P0.05)。二世代生长性能显著高于一世代和零世代(P0.05),一世代显著高于零世代(P0.05)。群体和世代间互作效应仅对2月龄重有显著影响(P0.05)。母本效应对生长性能无显著影响(P0.05)。本研究提示:高代杂种初生重低、育成期生长发育快,而成年体重与纯种荷斯坦牛无显著差异,在现有生产体系下实现最佳的遗传环境匹配,适宜在北方农区生产体系中推广养殖。     

牛用谷物蒸汽压片及其饲养效果

蒸汽压片是美国牛用谷物普遍使用的一种加工方式。蒸汽压片能够提高谷物营养物质、尤其是淀粉的消化率,提高奶牛的泌乳性能,提高肉牛的料重比。本文介绍了蒸汽压片工艺及其对牛代谢和生产性能的影响。     

波德代羊及其杂种羊血液蛋白多态性研究

运用聚丙烯酰胺凝胶电泳技术对首次引入我国的肉用品种绵羊波德代及其杂种一、二、三代和当地蒙古羊的血液蛋白(酶)多态性进行了检测分析。结果表明:波德代羊及其杂种和蒙古羊在Hb、Tf、Es三个基因座上存在多态性。其中Hb和Es的基因座均由两个等位基因控制,而Tf的基因座则由三个等位基因控制。从三个基因座的Nei氏平均基因杂合度估计绵羊品种内遗传变异,发现以蒙古羊为最低,其杂合度为0.3903。品种聚类分析也符合群体遗传学原理。     

Endemic stability for Theileria parva infections in Ankole calves of the Ankole ranching scheme, Uganda

A population-based study was carried out on the Ankole ranching scheme in south-west Uganda with the aim of determining the endemic status of Theileria parva infections. For this purpose, the age-related sero-prevalence of T. parva and the specific calf mortality associated with the parasite were assessed. Blood samples were collected from 931 Ankole calves of up to 12 months of age from 81 randomly selected herds. The relationship between rainfall pattern and whole-body Rhipicephalus appendiculatus counts was determined. The influence of tick control practices on East Coast fever-related calf mortality, and sero-positivity were also determined. A significant (r2 = 0.76, P = 0.000) association between R. appendiculatus counts and rainfall was observed. There was no significant (P > 0.05) association between theileriosis-related calf mortality, sero-positivity and the different tick control practices. Antibody prevalence based on the PIM ELISA was above 70% among calves of 6 months of age in 96% in all the herds. Theileria parva-related calf mortality determined by repeated herd visits and farm records ranged between 0 % and 5.4 %. It was concluded that endemic stability for theileriosis, caused by T. parva, existed in the study area, and that the risk of the occurrence of economically important outbreaks of East Coast fever in indigenous cattle was regarded as minimal under the prevailing conditions.     

A farming systems study of abortion in dairy cattle on the Atherton Tableland: I. Reproductive performance

Herd health records from 1983 to 1985 were analysed for a sample of 19 dairy farms on the Atherton Tableland in tropical north Queensland. Abortion and first service conception rates were calculated for each farm for each year. The association between abortion rate and stage of gestation at pregnancy diagnosis was investigated as well as the association between abortion rate and lactation status. There was a significant linear increase in abortion rate over the 3-year period, during which the mean rate was 7.3 +/- 2.1% (range 4.5% to 10.9%). There was also a significant variation in first conception rates during the same period, when the mean first service conception rate was 51.8% +/- 6.6% (range 42.4% to 65.8%). A significantly higher abortion rate was recorded in first lactation cows. Of 178 abortions in all lactation groups (1984), 20.3% were repeat abortions by the same cows. Of 163 abortions, a majority (80.4%) occurred during months 3 to 7 of gestation. No significant association was found between the timing of pregnancy diagnosis and occurrence of abortion.     

Productive performance of cattle in Botswana

Summary A field investigation was undertaken in several areas of Botswana to determine how management, environment and possibly aphosphorosis affected the bodily condition and reproductive performance of range cattle in these areas. Results indicated that poor management, overgrazing and poor watering facilities seriously impaired bodily condition and reproductive performance. Good management helps greatly to improve the situation. Aphosphorosis does occur in some areas but appears to be closely linked with malnutrition.

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Sumario Sellevó a cabo una investigación de campo en varias areas en Botswana para determinar como el manejo, ambiente y posiblemente la afosforosis afectaban la condición corporal y la performance reproductiva del ganado en pastoreo en estas areas. Los resultados indicaron que el manejo pobre, el sobrepastoreo y la pobreza de agua afectaron seriamente la condición corporal y el rendimiento reproductivo. El buen manejo ayuda enormemente en mejorar la situacion. La afosforosis ocurre en algunas areas pero parece estar estrechamente ligada a la malnutricion.

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Résumé Une enquête a été effectuée dans plusieurs régions du Botswana pour déterminer comment l'exploitation, l'environnement et l'aphosphorose influen?aient la condition physique et les facultés reproductrices du bétail nomade de ces régions. Les résultats montrent qu'une médiocre exploitation, le surpàturage et de faibles possibilités d'abreuvement diminuaient sérieusement la condition physique et les facultés reproductrices. Une bonne conduite aide beaucoup à améliorer la situation. L'aphosphorose s'observe dans quelques régions mais elle para?t être étroitement liée à la malnutrition.

     

Induction of parturition in dairy cattle and its effects on health and subsequent lactation and reproductive performance

OBJECTIVE: To determine the effect of induction of parturition on health, milk production and reproductive performance of dairy cows. DESIGN: A prospective cohort study in 62 dairy herds. PROCEDURE: Health, milk production and fertility indices were documented for 1449 dairy cows treated with dexamethasone trimethylacetate, with or without prostaglandin to induce calving. Equivalent data was collected for 603 untreated herd mates that calved at approximately the same time. RESULTS: The median interval from initial treatment to calving was 11 days. Induction was associated with a substantially lower calf survival and commercial value of surviving calves. Calf viability and value was lower when induced cows were at an earlier stage of pregnancy. Retained foetal membranes, photosensitisation and other problems were significantly more frequent in the induced group compared to the untreated group. Milk production of induced cows was approximately 4% lower than untreated ones, but the majority of reproductive indices were not significantly different between the two groups. CONCLUSIONS: The practice of induction of parturition in seasonal calving dairy herds is a reliable way of shortening the gestation period of cows. Costs associated with morbidity and mortality of induced cows and losses in lactation and calf production are offset by benefits of improved reproductive performance and more efficient management of the herd. The welfare aspects of induction on calf survival must be considered.     

Mitochondrial respiratory metabolism and performance of cattle

Two groups of cows were sampled to study variation of mitochondrial metabolism. The first group included 10 lactating and five gestating Holstein cows, representing available phenotypic extremes for milk yield. The second group included 13 Angus, 13 Brangus and 13 Hereford cows, representing available extremes within breeds for growth breeding value ratios. Consistently poor mitochondrial samples were obtained from gestating cows; these were excluded from analyses. Linear correlations of Holstein mitochondrial respiratory activities with sire-predicted difference for milk and milk fat ranged from -.35 to .15. Correlations of dam and cow indices and cow yields for milk with acceptor-stimulated mitochondrial respiration, oxidative phosphorylation efficiency (adenosine diphosphate:oxygen ratio [ADP:O ratio]) and adenosine triphosphate (ATP) synthesis rate were .25 to .48, consistently higher than for milk fat, -.06 to .17. No differences among beef breeds in mitochondrial respiration rates, coupling of respiration to phosphorylation, ADP:O ratio or ATP synthesis rate were detected by repeated measures analyses of variance. No patterns were evident among correlations of the mitochondrial characteristics and growth and milk traits in beef cattle. These initial findings indicate that variability in the mitochondrial respiratory activities measured has less relation to weaning and yearling growth traits of beef cattle than to milk yield of Holstein cattle.     

Reproductive and some peri-natal variables in a mixed breed beef cattle herd

SUMMARY: Calving success (CS), days to calving (DC), birth weight (BW) and calving ease (CE) were studied in a mixed breed (Hereford, Jersey × Hereford and Simmental × Hereford) beef cattle herd. DC was not normally distributed and a number of transformations failed in normalising it. Repeatabilities were estimated by analysis of variance. Inclusion (or exclusion) of non calvers and the transformations studied had little effect on the repeatability of DC, which ranged from 0.10 to 0.12. The repeatabilities for CS, BW and CE were 0.08, 0.26 and 0.03, respectively. The residual correlations of CS with DC and functions of DC were high (-0.68 or greater), whereas the correlations among DC and functions of DC were close to one. The correlations of DC with BW and CE varied little with the transformation applied to DC, ranging from 0.26 to 0.28 and 0.10 to 0.12, respectively. The correlation between BW and CE was 0.06. The study points to a number of problems associated with the use of DC as a reproductive variable in beef cattle. It is concluded that although DC is currently a useful field reproductive variable, the search for appropriate female reproductive traits should continue. ZUSAMMENFASSUNG: Reproduktions- und Perinatal-Variable in einer gemischtrassigen Fleisch-Rinderherde Abkalbeerfolg (CS), Tage bis Abkalbung (DC), Geburtsgewicht (BW) und Kalbeleichtigkeit (CE) wurden in einer gemischtrassigen (Hereford, Jersey × Hereford und Simmental × Hereford) Mutterkuhherde untersucht. DC waren nicht normalverteilt und konnte auch durch eine Reihe von Transformationen nicht normalisiert werden. Wiederholbarkeiten wurden mit Varianzanalyse gesch?tzt. Berücksichtigung (oder Nichtberücksichtigung) von Nichtkalbungen und die Transformationen hatten wenig Wirkung auf Wiederholbarkeit von DC, die zwischen 0,10 und 0,12 war. Wiederholbarkeiten für CS, BW und CE waren 0,08, 0,26 und 0,03. Die Restkorrelation von CS mit DC und Funktionen von DC waren hoch (- 0,68 oder st?rker), w?hrend Korrelationen zwischen DC und Funktionen von DC auch nahe 1 waren. Die Korrelationen von DC mit BW und CE schwankten wenig nach den verschiedenen Transformationen und bewegten sich zwischen 0,26 und 0,28 sowie 0,10 und 0,12. Die Korrelation zwischen BW und CE war 0,06. Die Untersuchung weist auf eine Reihe von Problemen, die sich durch die Verwendung von DC als Reproduktionsvariable von Fleischrindern ergeben. Es wird der Schlu? gezogen, da? DC derzeit zwar nützliche Information für die Praxis ist, da? aber das Suchen nach wissenschaftlich angemessenen weiblichen Reproduktionsmerkmalen fortgesetzt werden sollte. RESUMEN: Variables reproductivas y peri-natales en un rodeo de vacunos de carne de varias razas Las variables éxito al parto (CS), dias al parto (DC), peso al nacer (BW) y facilidad de parto (CE) se estudiaron en un rodeo de vacunos de carne compuesto de varias razas (Hereford, Jersey × Hereford y Simmental × Hereford). DC no estaba normalmente distribuida y una serie de transformaciones ensayadas fracasaron en normalizar esta variable. Las repetibilidades se estimaron por análisis de variancia. La inclusión (o exclusión) de las vacas falladas (no paridas) del análisis y las transformaciones estudiadas tuvieron poco efecto en la repetibilidad de DC, que varió de 0.10 a 0.12. Las repetibilidades de CS, BW y CE fueron 0.08, 0.26 y 0.03, respectivamente. Las correlaciones residuales de CS con DC y con funciones de DC fueron altas (valor absoluto 0.68 o mayor), mientras que las correlaciones entre DC y funciones de DC fueron cerca de uno. Las correlaciones de DC con BW y CE variaron poco con la transformación aplicada a DC, yendo (en valor absoluto) de 0.26 a 0.28 y 0.10 a 0.12, respectivamente. La correlación entre BW y CE fue de 0.06. El estudio apunta a una serie de problemas asociados con el uso de DC como variable reproductiva en vacunos de carne. Se concluye que aunque DC es actualmente una útil variable reproductiva de campo, la búsqueda de rasgos reproductivos de la hembra a ser incluídos en esquemas de evaluación genética de vacunos de carne debe continuar.     

Populations of the cattle tick (Boophilus microplus) on purebred Nellore,Ibage and Nellore × European crossbreds in the Brazilian savanna

Studies on purebred Nellore cattle and their crosses with Fleckvieh, Chianina, Charolais and the Ibagé breed (5/8 Aberdeen Angus, 3/8 Nellore) during 39 months in the field gave mean daily counts for engorging female ticks of 3.3, 25.2, 22.2, 21.0 and 59.7 per animal respectively. Annual fluctuations were similar in all groups; with the exception of the purebred Nellore mean counts are at levels considered dangerous for the stability of enzootic tick fever.     

淮猪及杂交后代肌纤维直径变化及其与肉质关系的研究

对不同品种和杂交组合肥育猪(淮猪、长淮、大长淮)采用单因子试验设计,在相同条件下,研究不同血缘比例对淮猪肌纤维直径的影响。结果表明:淮杂猪的背最长肌和股二头肌肌纤维直径显著高于淮猪(P<0.05)。淮猪的肌纤维直径介于中国地方猪与国外瘦肉型猪之间。肌纤维直径与胴体性状(瘦肉率、眼肌面积、背最长肌全重、背最长肌率、脂肪)呈较强的相关性。淮杂猪肉质理化性状中(肉色评分、大理石纹评分、贮藏损失)3项指标明显变差(P<0.05),但pH值变化不显著。作者认为淮猪杂交后代的肌纤维直径较纯种淮猪粗,淮杂猪肉质也较纯种淮猪差。     

Reproductive performance of crossbred and purebred male rabbits

The effect of buck genetic type and crossbreeding parameters on fertility and prolificacy were estimated using two rabbit sire lines and their reciprocal crosses. The relationship between the reproductive performance of inseminated multiparous does and several semen quality traits was also investigated. The semen characteristics evaluated were: pH (pH), mass and individual motility (MM, IM), percentage of viable spermatozoa (Vi), spermatozoa with normal apical ridge (NAR), normal spermatozoa (NSP), spermatozoa with morphological abnormalities of head (HAP), neck-midpiece (NAP), and tail (TAP), spermatozoa with the presence of proximal (PD) and distal (DD) cytoplasmic droplets.

Fertility was analysed as a continuous trait (kindling rate) or as a binary trait (success or failure of kindling). In the first case, the analysis was performed using GLM procedures of SAS v.8 according to a model that included the fixed factors of buck genetic type, number of ejaculates per pool and week of insemination. In the second case, fertility was analysed using GENMOD procedures of SAS v.8 according to a mixed model including the same fixed factors as before plus the physiological status of the does and the permanent random effect of female. Number of kits born alive and number of stillborn were analysed with MIXED procedures of SAS v.8 with the same model used for the analysis of fertility as a binary trait. Estimates of the estimable functions of crossbreeding genetic parameters of the lines were obtained from the solutions of the corresponding models by generalized least squares using GLM, GENMOD and MIXED procedures. Crossbreeding parameters were estimated according to the model of Dickerson. A linear regression was used to determine the relationship between fertility and litter size and the semen characteristics evaluated.

Significant differences in fertility were observed among buck genetic types, which were favourable to type R. Differences between lines in maternal genetic effects were relevant and favourable to type R for fertility. Individual heterosis was important but unfavourable for fertility.

A slight correlation was obtained between all semen quality traits and fertility and prolificacy. Two multiple models were found for fertility, including NAP, IM, NSP, buck genetic type and Vi in one model or NAR in other model. Individual motility had an important positive effect, while NAP had a small negative effect. When MM, TAP and buck genetic type were included in a multiple model for the number of kits born alive, both MM and TAP had significant small effects. Individual motility and DD appeared to be related to number of kits stillborn, but only DD had a significant although negligible effect.