首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.

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.

  相似文献   

2.
Tropical Animal Health and Production - The aim of this study was to assess the reproductive performance of Ankole cattle and its crossbreds with Friesian (F), Jersey (J), and Sahiwal (S). The...  相似文献   

3.
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.
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.

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.
  相似文献   

4.
The performance was compared of cows sired by Holstein, Jersey or Brown Swiss bulls out of Holstein-Friesian×Gir dams of 1/2 to 3/4 Holstein-Friesian content. The animals were kept in a single herd under the same management. The data were analysed by least-squares techniques under a model that included the fixed effects of breed of sire, Bos taurus fraction of the dam, parity, year and season of calving, and a random cow effect. Based on 480 observations, the milk yields per lactation for the Holstein, Jersey and Brown Swiss sired groups were 2821±163, 2320±61 and 2418±119 kg, respectively. The corresponding means for fat yield per lactation were 96.9±6.6, 86.8±2.5 and 92.8±4.8 kg; for protein yield per lactation were 85.3±5.1, 71.3±1.9 and 76.3±3.7 kg; for lactation length, 339±18, 283±7 and 313±14 days for fat percentage, 3.37±0.10, 3.73±0.04 and 3.77±0.07%; and for protein percentage, 3.02±0.05, 3.10±0.02 and 3.16±0.04%. The respective calving intervals were 487±24, 408±11 and 461±245 days. The yields of milk and protein per day of calving interval were similar in the Jersey and Holstein sired groups, while the former had higher yields of fat, implying that production economics might favour the smaller Jersey crosses in production systems in which the males were not reared. Crossing with Brown Swiss did not improve performance over the Holstein sired crosses.  相似文献   

5.
A study with the objectives of estimating breed differences, heterosis and recombination effects as well as heritabilities (h2) and repeatabilities (r2) for age at first calving (AFC), calving interval (CI), days open (DO) and number of services per conception (SPC) was conducted using reproduction records collected from 1496 cows comprising purebred Boran (B), Friesian (F), crosses of Friesian and Jersey (J) with Boran breeds. The crossbred cow groups included four F × B crosses [1/2F:1/2B(F1), 1/2F:1/2B(F2), 5/8F:3/8B and 3/4F:1/4B], three J × B crosses [1/2J:1/2B(F1), 1/2J:1/2B(F2) and 3/4J:1/4B] and one three‐breed cross (1/4F:1/4J:1/2B). The crossbreeding parameters were estimated using a repeatability animal model for CI, DO and SPC, and a unitrait animal model for AFC. The overall least‐squares means estimated were: 38.3 ± 0.26 months, 435 ± 4 days, 145 ± 10 days and 1.58 ± 0.03 (number) for AFC, CI, DO and SPC, respectively. The breed additive effects of F and J were only significant (p < 0.01) for AFC. Relative to B, both F and J additive contributions for AFC were ?5.4 ± 0.5 and ?5.5 ± 1.9 months, respectively. Crossing the B with F and J breeds also resulted in significant heterosis (p < 0.05) ranging from 10 to 21% in all traits. The estimated recombination loss was only significant for AFC (2.8 ± 1.0 months) for F × B crosses. Heritability estimates were high for AFC (0.44 ± 0.05) and low for CI (0.08 ± 0.03), DO (0.04 ± 0.03) and SPC (0.08 ± 0.02). The corresponding estimates for the repeatability (r2) were 0.14 ± 0.02 and 0.14 ± 0.02 for CI and DO, respectively. The permanent environmental effect for SPC was zero. These findings show that breed differences between F or J and B, and the individual cow variations are low for reproductive traits studied, except for AFC. Heterotic effects seem to be the major genetic causes for the improved reproductive performances in both the F × B and J × B crossbred cows.  相似文献   

6.
Gene action and heterosis in seven lifetime traits of Holstein‐Friesian × Sahiwal crosses was studied by fitting genetic additive—dominance and Dickerson, Sheridan models. The additive—dominance model is found adequate for all the traits except ‘average milk yield per day of total productive life’. The heterosis measured from mid‐parent varied from 15% in ‘total life’ to 108% in ‘milk yield from all available lactations’. Heterosis measured from superior parent ranged from 6% in ‘total milk yield of first three lactations’ to 75% in ‘milk yield from all available lactations’. The larger heterosis observed in some of the lifetime traits is attributed as the direct consequence of longer productive life in F1s compared to parental breeds. On the basis of the predicted performance of some of the nonavailable grades like 2/3 exotic, creation of synthetics is mooted.  相似文献   

7.
The study was conducted to assess early-expressed reproductive traits of Boran cattle and their crosses with Jersey and Holstein Friesian (HF). The traits studied were age at first services (AFS), number of services for first conception, age at first calving (AFC), first dry period (FDP), first calving interval (FCI), and first service period (FSP). Genetic group and period of birth/calving had a significant (p?<?0.05) effect on reproductive traits. The Boran cattle were inferior to HF or Jersey crosses. First crosses (F 1) for Jersey and Boran (50 % Jersey: 50 % Boran) showed a significantly (p?<?0.05) younger AFS (by 7.25 months) and AFC (by 10.75 months), had shorter FCI (by 63.27 days), FDP (by 61.13 days), and FSP (by 60.3 days), and needed less (by 0.35) numbers of services per first conception as compared to the Boran cattle. The F 1 for Jersey and Boran (50 % Jersey: 50 % Boran) crosses showed better performance than the F 1 for HF and Boran (50 % HF: 50 % Boran). Heritability values for AFS and AFC were the highest and were estimated at 0.51?±?0.10 and 0.49?±?0.13, respectively, and lowest heritability was recorded for FDP (0.02?±?020) and FSP (0.10?±?0.29). The genetic correlation was highest (0.10?±?0.20) between AFS and AFC and was lowest (?0.01?±?0.66) between FCI and FSP. The breed additive for Jersey was only significant (p?<?0.01) for AFS and AFC. The crossing of HF with Boran cattle has desirably reduced 9.16?±?2.88 months in AFS; the corresponding reduction in AFS was 3.49?±?3.59 months by crossing with Jersey. The performance comparisons and genetic and crossbreeding parameters indicated that crossbreeding of Boran with HF or Jersey can improve reproductive performance.  相似文献   

8.
The effects of outdoor raising of Brown Swiss and Holstein replacement calves in individual hutches were studied on a farm having northern Mediterranean climatic conditions. A total of 240 female calves was used with 30 calves of each breed and born in each of the four seasons. The animals were kept for 3 months in individual hutches and then in groups of 10 until 6 months of age. The birth weights of the Brown Swiss and Holstein calves were 37.2±0.21 and 37.9±0.22, respectively. The average birth weights were highest in spring and lowest in winter. Breed and seasonal effects were evident at 6 months. The live weights for the two breeds at 6 months were 114.1±1.3 and 126.3±1.5 kg, respectively. The numbers of health disorders were significantly higher in the first month of life. Mortalities occurred in the following months, being 2.5% in Holsteins and 5% in Brown Swiss by 6 months of age. The results indicated that calves can be reared outdoors successfully.  相似文献   

9.
An epidemiological investigation was conducted on farms in Tororo and Soroti districts of Uganda from January to February 2000 to determine the cause of reported persistent mortality of cattle. Blood and faecal material of 98 cattle comprising of 33 Friesians, 58 Zebu and 7 Sahiwal were examined. Results revealed that seven (7.1 %) cattle had trypanosome infection, mainly due to Trypanosoma vivax and T. brucei, 17 (17.3%) Fasciola infection, 28 (28.6%) gastrointestinal nematode infection, 33 (33.7%) Theileria sp. infection and 13 (13.3%) Anaplasma marginale infection. Mixed infections were detected in 30%, 20.6% and 43 % of the Friesian, Zebu and Sahiwal cattle respectively. Anaemia (PCV < 25) was detected in 24%, 19% and 14% of the Friesian, Zebu and Sahiwal cattle respectively. Persistent mortality of cattle on these farms could have been due to either single or mixed parasitic infections probably exacerbated by malnutrition.  相似文献   

10.
Breed additive and non‐additive effects plus heritabilities and repeatabilities for milk yield per lactation (LMY), milk yield per day (DMY), lactation length (LL), annual milk yield (AMY), annual milk yield per metabolic body weight (AMYBW) and cow weight at calving (BW) were estimated for 5464 lactation records collected from purebred Boran (B), Friesian (F), and crosses of Friesian and Jersey (J) breeds with the Boran breed raised in the tropical highlands of Ethiopia. Single trait analysis was carried out by using two equivalent repeatability animal models. In the first model the genotype was fitted as a fixed group effect, while in the second model the genotype was substituted by breed additive, heterotic and recombination effects fitted as fixed covariates. Both the F and J breed additive effects, measured as a deviation from the B breed were significant (p < 0.01) for all traits, except for BW of the J. The F and J additive contributions were 2774 ± 81 and 1473 ± 362 kg for LMY, 7.1 ± 0.2 and 4.8 ± 0.8 kg for DMY, 152 ± 7 and 146 ± 31 days for LL, 2345 ± 71 and 1238 ± 319 kg for AMY, 20.6 ± 0.9 and 18.9 ± 4.3 kg for AMYBW, and 140 ± 4 and ?21 ± 22 kg (p > 0.05) for BW. The heterotic contributions to the crossbred performance were also positive and significant (p < 0.01) for all traits. The F1 heterosis expressed as a deviation from the mid‐parent values were 22 and 66% for LMY, 11 and 20% for DMY, 29 and 29% for LL, 21 and 64% for AMY, 42 and 42% for AMYBW, and 2% (p < 0.05) and 11% for BW for the F × B and J × B crosses, respectively. The recombination effect estimated for the F × B crosses was negative and significant for LMY (?526 ± 192 kg, p < 0.01), DMY (?3.0 ± 0.4 kg, p < 0.001), AMY (?349 ± 174 kg, p < 0.05) and BW (?68 ± 11 kg, p < 0.001). For the J × B crosses the recombination loss was significant and negative only for DMY (?2.2 ± 0.7 kg, p < 0.05) and BW (?33 ± 17 kg, p < 0.05). The direct heritabilities (h2) estimated for LMY, DMY, LL, AMY and AMYBW were 0.24 ± 0.04, 0.19 ± 0.03, 0.13 ± 0.03, 0.23 ± 0.04 and 0.17 ± 0.05, respectively. Based on the genetic parameters estimated, the best breeding strategy to increased milk production under highland Ethiopian conditions is to apply selection on purebred base populations (Boran and Friesian) and then crossing them to produce F1 dairy cows. However, for breeding decision based on total dairy merit, further investigations are needed for traits such as milk quality, reproduction, longevity and survival.  相似文献   

11.
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.  相似文献   

12.
13.
Variance and covariance components for sire of cow and sire of insemination of fertility traits were estimated by parity using REML procedures. Subsequently direct genetic and maternal components were calculated. Heritabilities for 56-day non-return rate, conception rate (heifers, parity one to three) and days open (parity one to three) varied between 0.007 and 0.049. The heritability for age at conception in heifers was 0.192. The maternal component for days open was greater than the direct genetic component. The genetic correlations between sire of insemination and sire of cow for non-return rate changed from −0.29 in heifers to 0.59 in parity three, that for conception rate from −0.74 to 0.48. The relation between maternal and direct genetic components changed from −0.94 to 0.26 and −0.97 to 0.12 for non-return and conception rates, respectively. Changes in correlations for days open from parity one to three were smaller. The results indicated that the genetic correlation between the sire of cow components for non-return and conception rate in heifers, first parity and older cows may differ from unity.  相似文献   

14.
15.
Two short-term feeding trials (3 weeks on each treatment) using a total of 54 lactating cows in a 3 × 3 Latin square design were carried out to determine the ad libitum roughage intake of Simmental (SI), Brown Swiss (BS) and Holstein Friesian (HF) cows, respectively. The cows were fed rations with 0. 25 and 50% of dry matter (DM) as concentrates, the rest as roughage. The roughage consisted of 31.5% hay, 38.1% grass silage and 30.4% maize silage.SI, BS and HF cows consumed 10.7, 11.0 and 12.2 kg DM day−1 roughage, equivalent to 87, 93 and 105 g kg−0.75 bodyweight. For concentrate groups 0, 25 and 50%, roughage intake decreased from 12.8 to 11.7 and 9.4 kg DM day−1. The substitution rate derived from linear regression was 0.36 kg DM kg−1 DM. The milk yield was increased from 14.1 to 16.7 and 19.7 kg by feeding concentrates, while milk protein concentration increased from 3.0 to 3.2 and 3.4% and milk fat concentration decreased from 4.3 to 4.2 and 4.1%.The regressions of forage intake (kg DM) on milk yield (kg energy-standardized milk (ESM)) showed big differences between breeds, but also between concentrate levels. The regression slopes were 0.04, 0.23 and 0.28 for SI, BS and HF cows.  相似文献   

16.
Lactation traits and reproductive performance of three trials of crossing Holstein cattle (H) and German Friesians (F) raised in a hot climatic were evaluated. The first 90-day (M90), 305-day (M305) and total milk yield (TMY), 305-day milk yield per day of calving interval (MCI1), total milk yield per day of calving interval (MCI2) along with length of lactation period (LP), age at first calving (AC1) and calving interval (CI) were used. For these traits, a genetic model was applied for each trial separately to obtain estimates of individual (GI) and maternal (GM) additive effects, individual (HI) and maternal (HM) heterosis and individual recombination effect (RI). Data of 8045 normal lactations from the three trials were analysed. Among the crossbreds obtained in the three trials, cows of ¾H¼F ranked first in their lactational performance. Estimates of GI and GM were generally large and in favour of H cows (daughters) and dams for most milk-yield traits, CI and AC1 in the three trials. Estimates of HI in crossbred cows for milk traits, CI and AC1 were mostly negative and reveal that crossing F with H was associated with a reduction in milk-yield traits, shorter CI and earlier AC1 along with longer LP in the three trials. Estimates of HM for milk yields, LP, AC1 and CI in daughters of crossbred dams were mostly negative. Recombination losses in crossbred cows were negative for milk-yield traits, AC1 and CI in most cases.  相似文献   

17.
Lactation traits and reproductive performance of three trials of crossing Holstein cattle (H) and German Friesians (F) raised in a hot climatic were evaluated. The first 90‐day (M90), 305‐day (M305) and total milk yield (TMY), 305‐day milk yield per day of calving interval (MCI1), total milk yield per day of calving interval (MCI2) along with length of lactation period (LP), age at first calving (AC1) and calving interval (CI) were used. For these traits, a genetic model was applied for each trial separately to obtain estimates of individual (GI) and maternal (GM) additive effects, individual (HI) and maternal (HM) heterosis and individual recombination effect (RI). Data of 8045 normal lactations from the three trials were analysed. Among the crossbreds obtained in the three trials, cows of 3/4H 1/4F) ranked first in their lactational performance. Estimates of GI and GM were generally large and in favour of H cows (daughters) and dams for most milk‐yield traits, CI and AC1 in the three trials. Estimates of HI in crossbred cows for milk traits, CI and AC1 were mostly negative and reveal that crossing F with H was associated with a reduction in milk‐yield traits, shorter CI and earlier AC1 along with longer LP in the three trials. Estimates of HM for milk yields, LP, AC1 and CI in daughters of crossbred dams were mostly negative. Recombination losses in crossbred cows were negative for milk‐yield traits, AC1 and CI in most cases.  相似文献   

18.
19.
Breed additive and non-additive effects, and heritabilities of birth weight (BWT), weaning weight (WWT), 6 months weight (SMWT), yearling weight (YWT), eighteen months weight (EWT), 2 years weight (TWT) and average daily weight gain from birth to 6 months (ADG1) and from 6 months to 2 years (ADG2) were estimated in Ethiopian Boran (B) cattle and their crosses with Holstein Friesian (F) in central Ethiopia. The data analysed were spread over 15 years. Ethiopian Boran were consistently lighter (p < 0.01) than the B-F crosses at all ages. Ethiopian Boran also gained lower weight than all the crosses. At birth, 50% F crosses were significantly (p < 0.01) lighter than all the other crosses. However, the differences in SMWT, YWT, EWT, TWT, ADG1 and ADG2 were all non-significant among the crosses. The individual additive breed differences between B and F breeds were positive and significant (p < 0.01) for all traits. The individual heterosis effects were significant (p < 0.05) for all traits except WWT for which the effect was non-significant. The maternal heterosis effects were significant (p < 0.01) for BWT (2.5 kg) and WWT (-3.0 kg). The heritability estimates for all traits in B and crosses were generally moderate to high indicating that there is scope for genetic improvement through selection. Selection within B and crossbreeding should be the strategy to enhance the growth performance under such production systems.  相似文献   

20.
A Weibull mixed survival model was used to study the effect of a change in the housing system on length of productive life (LPL) in dairy cows. The data set included records on 71,469 Swiss Brown cows in 1674 farms in eastern and central Switzerland. About 36% of the records were right-censored. The observation period lasted from January 1, 1988 to May 1, 2001. During this period, 517 farms changed their housing conditions from a tie-stall barn to a loose housing system. Besides a random time-dependent effect of herd–year–season, the model included fixed effects of housing system, lactation number and stage of lactation, within herd and parity production level (all time-dependent), and age at first calving (time-independent). All effects had a significant effect on LPL at a level of p < 0.001. Cows in loose housing systems showed the lowest risk ratios of being culled (0.93) compared to the reference system tie-stall barn (1.00). The highest relative culling rate (1.09) was observed within the changing period from tie-stall barn to loose housing system. Within the first three lactations, the relative culling risk increased stepwise with lactation stage. The hazard slightly increased from first until lactation number 8 and higher. The relative culling rates were highest (2.22) for cows yielding less than 90% compared to herd-mates of the same lactation number, whereas the lowest risk ratios were estimated for animals yielding more than 110% compared to their reference group (0.64). When heifers were older than 3 years at first calving, there was a tendency towards a higher relative culling risk (1.06).  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号