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1.
The objective was to evaluate the effect of cow genetic group, nutritional level and their interaction on some economically important traits of dual-purpose herds managed under field conditions. Nine herds were monitored during a production cycle in Yucatan, Mexico. Herds were grouped into four nutritional levels (NL) based on the metabolizable energy (ME) apparently available on pasture, nutritional management, and milk production. Cows were classified into three genetic groups (GG): low (≤25%), middle (25–75%) and high (≥75%) graded for Bos taurus inheritance. Total milk sold (TMS), days in milk (DIM), TMS adjusted to DIM within each NL (TMSA), body condition score (BCS) at calving, changes of BCS during lactation (CBCS), calf weaning weight (WW), age at weaning (AW), kg of calf weaned per cow (KWC) and calf mortality were studied. The statistical model included the fixed effects of NL, GG, month of calving (MC), parity number (PN) and BCS at calving and GG × NL interaction. The effects of NL, GG, MC, PN and GG × NL were significant (p < 0.05) for TMS, KWC. As expected, TMS increased with NL from 562.4 ± 106 kg for NL1 to 2366.3 ± 100.1 kg for NL4. KWC was greatest for NL2 (138.6 kg) followed by NL1 (135 kg); the lowest KWC corresponded to NL4 (96.0 kg) (p < 0.05). TMS values for the middle (1727 ± 94.7 kg) and the high graded GG (1603.5 ± 83.5 kg) were twice those for the low graded GG cows (828.5 ± 95 kg) (p < 0.05). KWC was also higher for the middle graded group (152.8 kg) than for the low or (104 kg) or the high graded GG (118 kg) (p < 0.05). With better nutrition cows of all GG improved their milk performance but not the calf traits. CBCS was negative for all GG. The highest BCS lost was for cows in NL1 and NL2 and for cows in the high graded GG (p < 0.05).  相似文献   

2.
Data collected on a privately owned ranch located in the Machakos District of Kenya at approximately 2 degrees latitude south of the equator at an elevation varying from 1,675 to 2,000 m were analysed on five breed groups of cows: (1) purebred Boran, (2) 1/2 Charolais-1/2 Boran (1/2 C-1/2 B), (3) 3/4 Boran-1/4 Charolais (3/4 B-1/4 C), (4) 1/2 Ayrshire-1/2 Boran (1/2 A-1/2 B) and (5) 1/2 Santa Gertrudis-1/2 Boran (1/2 SG-1/2 B). The maternal traits evaluated included age at first calving, calving interval, calf weight at weaning and cow productivity index (calf weight weaned annually per cow calving). Mean cow productivity index for all cows was 192 kg; for purebred Boran, 174 kg; for 1/2 C-1/2 B, 200 kg; for 3/4 B-1/4 C, 191 kg; for 1/2 A-1/2 B, 210 kg; and for 1/2 SG-1/2 B, 185 kg. Cow breed groups 1/2 C-1/2 B, 3/4 B-1/4 C, 1/2 A-1/2 B and 1/2 SG-1/2 B exceeded (P less than 0.01) purebred Boran by 14.9, 9.8, 20.7 and 6.3%, respectively, in cow productivity index.  相似文献   

3.
The aim was to compare the effects of two production systems on performance, carcass traits and physical‐mechanical characteristics of leather from Beefalo‐Nellore steers and heifers and to determine if the response to the production system was similar for both genders. A total of 40 Beefalo‐Nellore cattle, 20 steers and 20 heifers, were evaluated. Animals were divided into two production systems: slaughtered at 15 (intensive system) or 26 (extensive system) months of age. In the intensive system, all animals received a ration containing 600 g/kg corn silage and 400 g/kg concentrate. In the extensive system, animals were kept on a pasture predominantly based on Brachiaria sp. and supplemented with 2 kg/day concentrate. In the intensive system, there was no difference in slaughter weight (470 kg body weight) between steers and heifers but steers in the extensive system had greater slaughter weight than heifers (463 and 428 kg body weight, respectively). Leather weight was higher for animals in the intensive than extensive system but there was no difference in leather weight once excess fat was removed. Leather quality from Beefalo‐Nellore cattle slaughtered at 15 or 26 months of age is similar although carcass yield is higher for cattle slaughtered at a younger age.  相似文献   

4.
Livestock keeping is the mainstay for the pastoral community while also providing social and cultural value. This study ranked main production constraints and cattle diseases that impacted livelihood and estimated herd prevalence, incidence rate, and impact of diseases on production parameters in a semiarid pastoral district of Narok in Kenya. Data collection employed participatory techniques including listing, pairwise ranking, disease incidence scoring, proportional piling, and disease impact matrix scoring and this was disaggregated by gender. Production constraints with high scores for impact on livelihood included scarcity of water (19 %), lack of extension services (15 %), presence of diseases (12 %), lack of market for cattle and their products (10 %), and recurrent cycle of drought (9 %). Diseases with high scores for impact on livelihood were East Coast fever (ECF) (22 %) and foot and mouth disease (FMD) (21 %). High estimated incidence rates were reported for FMD (67 %), trypanosomosis (28 %), and ECF (15 %), while contagious bovine pleuropneumonia (CBPP) had an incidence rate <1 %. Milk yield was affected by FMD, ECF, and trypanosomosis, while ECF was the cause of increased mortality. FMD, ECF, CBPP, and brucellosis caused increased abortion, while effect of gender and location of study was not significant. Despite CBPP being regarded as an important disease affecting cattle production in sub-Sahara Africa, its estimated incidence rate in herds was low. This study indicates what issues should be prioritized by livestock policy for pastoral areas.  相似文献   

5.
Indigenous chicken (IC) and their production systems were characterized to understand how the whole system operates for purposes of identifying threats and opportunities for holistic improvement. A survey involving 594 households was conducted in six counties with the highest population of IC in Kenya using structured questionnaires. Data on IC farmers’ management practices were collected and analysed and inbreeding levels calculated based on the effective population size. Indigenous chicken were ranked highest as a source of livestock income by households in medium- to high-potential agricultural areas, but trailed goats in arid and semi-arid areas. The production system practised was mainly low-input and small-scale free range, with mean flock size of 22.40 chickens per household. The mean effective population size was 16.02, translating to high levels of inbreeding (3.12%). Provision for food and cash income were the main reasons for raising IC, whilst high mortality due to diseases, poor nutrition, housing and marketing channels were the major constraints faced by farmers. Management strategies targeting improved healthcare, nutrition and housing require urgent mitigation measures, whilst rural access road network needs to be developed for ease of market accessibility. Sustainable genetic improvement programmes that account for farmers’ multiple objectives, market requirements and the production circumstances should be developed for a full realization of IC productivity.  相似文献   

6.
7.
In an on-farm trial conducted amongst the Maasai pastoralists in Nkuruman and Nkineji areas of Kenya between April 2004 and August 2005 designed to evaluate the effectiveness of a synthetic tsetse repellent technology, we assessed the relationship between tsetse challenge and trypanosomosis incidence in cattle. Six villages were used in each area. Each of these villages had a sentinel cattle herd that was screened for trypanosomosis on monthly basis using buffy coat technique. Animals found infected at each sampling were treated with diminazene aceturate at 7 mg kg(-1) body weight. Treatments administered by the owners over the sampling intervals were recorded as well. Tsetse flies were trapped at the time of sampling using baited stationary traps and apparent tsetse density estimated as flies per trap per day (FTD). A fixed proportion (10%) of the flies was dissected and their infection status determined through microscopy. Blood meals were also collected from some of the flies and their sources identified using enzyme-linked immunosorbent assay (ELISA). Tsetse challenge was obtained as a product of tsetse density, trypanosome prevalence and the proportion of blood meals obtained from cattle. This variable was transformed using logarithmic function and fitted as an independent factor in a Poisson model that had trypanosomosis incidence in the sentinel cattle as the outcome of interest. The mean trypanosomosis incidence in the sentinel group of cattle was 7.2 and 10.2% in Nkuruman and Nkineji, respectively. Glossina pallidipes was the most prevalent tsetse species in Nkuruman while G. swynnertoni was prevalent in Nkineji. The proportions of tsetse that had mature infections in the respective areas were 0.6 and 4.2%. Most tsetse (28%) sampled in Nkuruman had blood meals from warthogs while most of those sampled in Nkineji (30%) had blood meals from cattle. A statistically significant association between tsetse challenge and trypanosomosis incidence was obtained only in Nkuruman when data was pooled and analyzed at the area but not at the village-level. In the later scenario, lagging tsetse challenge by 1 month improved the strength but not the significance of the association. These findings show that when the spatial unit of analysis in observational studies or on-farm trials is small, for instance a village, it may not be possible to demonstrate a statistically significant association between tsetse challenge and trypanosomosis incidence in livestock so as to effectively control for tsetse challenge.  相似文献   

8.
A bio-economic model was developed to evaluate utilization of beef bulls in a variety of production systems. The model can simulate life-cycle production of both beef and dairy cow herds with or without an integrated feedlot system. The Markov chain approach is used to simulate herd dynamics. The herd is described in terms of animal states and possible transitions among them. Equilibrium herd structures of the integrated production systems are calculated in their stationary states. The economic efficiency of each system is a function of biological traits of animals and of management and economic parameters. The model allows estimation of marginal economic values for 16 traits separately in each system. The economic weight for each trait or direct and maternal trait component in each selection group and breed of interest is then calculated as the weighted sum of the economic values for the trait in all production systems in which the selection group has an impact. Weighting factors for each system are computed as the product of the number of discounted expressions for direct and maternal trait components transmitted in that system by the selection group and the proportion of total cows belonging to each system.  相似文献   

9.
Summary Since no figures were available on the frequency of occurrence of oesophageal papillomata in cattle, the prevalence in cattle in Kenya was determined by a random survey at the largest abattoir in the country. Interest was stimulated by the report of Plowright (1955) and by the author's observations that oesophageal papillomata were present in cattle with rumenal carcinoma in the Nasampolai valley, Kenya. Oesophageal papillomata were found in46 of752 oesophagi examined (6·1 per cent). The cattle originated from various geographical areas of Kenya with varying climatic conditions and vegetation.
Sumario Desde que no hubieron datos sobre la ocurrencia de papilomas en el esófago en ganado vacuno, su incidencia en el ganado bovino en Kenya fue determinada mediante una encuesta en el matadero mas grande del pais. El interés fue estimulado por el reporte de Plowright (1955) y por las observaciones de los autores de que papilomas en el esófago estaban presentes en ganado con carcinoma ruminal en el valle de Nasampolai en Kenya. Papilomas en el esófago fueron encontrados en 46 de 752 esófagos examinados (6·1 por ciento). El ganado se originaba de diversas areas de Kenya de diversas condiciones climáticas y de diversa vegetación.

Résumé Comme il n'existe aucune donnée disponible sur la fréquence de la papillomatose oesophagienne du bétail au Kenya, l'importance de cette affection a été déterminée par une enquête au hasard dans le plus grand abattoir du pays. L'intérêt de cette enquête découlait grandement du rapport de Plowright (1955) et des observations des auteurs qui avaient montré que la papillomatose oesophagienne se trouvait associée au carcinome du rumen chez le bétail de la Vallée de Nasampolai au Kenya. Cette papillomatose fut trouvée sur 46 des 752 oesophages examinés (6,1 p. 100). Ces animaux venaient des régions très diverses du Kenya, dans lesquelles les conditions climatiques et la végétation étaient différentes.


On secondment from the A.R.C. Institute for Research on Animal Diseases Compton, Berkshire, England.

This work was carried out during a period of secondment to the University of Nairobi Medical School, Nairobi, Kenya.  相似文献   

10.
Summary Skin infections in cattle caused by Corynebacterium ovis, either as the main pathogen or in association with other organisms, was investigated on a Kenya ranch. The morbidity rate was approximately 25% involving more than 3,000 cattle and the condition appeared to be highly infectious. Three treatment regimes were instituted and the most effective proved to be lancing and irrigating the large abscesses with iodine solution.
Infeccion Corinebacterica Del Ganado En Kenia
Resumen Se investigaron en un rancho de Kenia, infecciones de la piel causadas porCorynebacterium ovis como principal patógeo o en asociación con otros organismos. La tasa de morbilidad fué de aproximadamente 25% siendo la condición altamente contagiosa. Se instituyeron tres tratamientos siendo el más efectivo la ruptura de los abscesos y su irrigación con una solución yódica.

Infection Corynebacterienne Du Betail, Au Kenya
Résumé Des infections cutanées du bétail causées parCorynebacterium ovis, soit en tant que germe pathogène dominant soit en association avec d'autres organismes ont eté constatées dans un ranch du Kenya. Le taux de morbidité a été de 25 p.100 environ pour plus de 3 000 animaux, et cette maladie est apparue extrêmement infectieuse. Trois traitements ont été institués, le plus satisfaisant consistant dans la ponction des abcès les plus importants et leur lavage par irrigation avec une solution iodée.
  相似文献   

11.
Assessment of livestock production constraints in the smallholder dairy systems in the western Kenya highlands was carried out using both qualitative and quantitative epidemiological methods. Rapid rural appraisals (qualitative) were conducted in rural and peri-urban areas. A cross-sectional survey (quantitative) was then conducted on a random sample of farms in the study area. Diseases, poor communication, lack of marketing of livestock produce, lack of artificial insemination services, and feed and water shortages during the dry season were identified as the major constraints to cattle production in both areas. Tick borne diseases (especially East Coast fever) were identified as the major constraint to cattle production. Qualitative methods were found to be more flexible and cheaper than the quantitative methods by a ratio of between 2.19-2.0. The two methods were found to complement each other. Qualitative studies could be applied in preliminary studies before initiating more specific follow up quantitative studies.  相似文献   

12.
In Pabna district, Bangladesh there are two cattle production systems: a draught-oriented system with local Deshi cattle and more milk-oriented production with Pabna Milking Cow (PMC) stock. Deshi animals are smaller than PMC animals. More PMC cows are milked than Deshi cows and the milk off-take of PMC cows is much higher. The calving interval in Deshi cows is one year longer than in PMC cows. The great majority of the bullocks and the bulls are used as draught animals. More than 80% of the Deshi cows also have to work compared with only about half of the PMC cows. The milk off-take of cows used for draught work is 30% less than that of other cows. One of the major differences between the two systems is that PMC cows have access to grazing along the rivers. These areas are increasingly taken up for cropping and the traditional Pabna milk production farming system is gradually being replaced.  相似文献   

13.
14.
A total of 620 bovine faecal samples collected from unselected animals brought for post-mortem to the Department of Veterinary Pathology and Microbiology or from animals in the Kabete (Kenya) practice area of the Faculty of Veterinary Medicine were examined to determine the types and prevalence of Eimeria spp. present. Coccidian oocytes were detected in 67.4% of the samples and eight different species of Eimeria were recognized. The species detected (and their prevalence) were E. bovis (79.0%), E. zuernii (60.2%), E. ellipsoidalis (26.1), E. cylindrica (13.4%), E. auburnensis (28.4%), E. alabamensis (10.3%), E. subspherica (5.0%) and E. wyomingensis (6.1%). E. bovis and E. zuernii led to few cases of clinical coccidiosis and the greatest number of E. bovis in one of the samples from the clinical cases was 30,600 oocysts per gram of faeces (OPG). Age and seasonal variation appeared to have an influence on the intensity of infection.  相似文献   

15.
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   

16.
The aim of this study was to investigate the spread of infection and population dynamics of ovine coccidosis under dairy sheep production systems in the Mediterranean area, taking into account differences between management systems, lambing season and climatic conditions. Data were collected from six (intensive and semi-intensive) dairy sheep flocks located either in the North or the South of Greece, with groups of lambs born during two consecutive lambing periods (autumn, spring) from each flock. Faecal consistency and oocyst excretion were recorded from faecal samples taken from 220 lambs in total, starting at days 7-9 after lambing and subsequently every 6 days for 5 times. Eleven Eimeria species including the highly abundant pathogenic E. ovinoidalis and E. crandallis were isolated. The onset of excretion was noted from 13 to 33 days after birth with a peak at 19-21 days. The cumulative incidence of infection per flock until the end of the study ranged from 64.29% to 100% during both lambing periods. A significant tendency for animals to get infected earlier during spring lambing was observed. This trend was even higher for lambs from farms located in the South and is possibly related to the higher contamination level of the farms after lambing during that time. Predominantly subclinical cases of coccidiosis were observed during the course of the study with a relatively low proportion of diarrhoeic faeces which did not significantly differ between the two rounds. Considering the significance of dairy sheep production in the area and the economic losses that can be caused by eimeriosis, monitoring of infection levels in the farms, taking into account the lambing period and environmental conditions, is highly recommended.  相似文献   

17.
Gene-flow methodology was used to calculate the cumulative discounted expressions (CDE) for annual/lactation, replacement heifer, cull cow, birth, yearling, and slaughter traits in alternative cattle production systems. Generic equations were presented and parameters representing dairy-beef production systems in Ireland and Brazil were inputted. Cumulative discounted expressions using input parameters from a hypothetical purebred dairy production system with poor cow longevity were also calculated. Cumulative discounted expressions were calculated assuming either an initial purebred or crossbred mating within each production system. Absolute and relative differences in CDE existed among trait categories across the three alternative production systems investigated. For example, the CDE of beef-related traits accruing from an initial purebred mating ranged from 0.42 to 0.75 CDE of an annual/lactation trait across the three contrasting systems investigated which differed in various input parameters. Such variation may alter the relative emphasis of traits on overall profitability thereby contributing to genotype by environment interactions. The results of this study highlight the necessity to consider auxiliary traits in sire selection over and above those representing the principal intended use of the sire. This was particularly so for integrated dairy-beef cattle production systems.  相似文献   

18.
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Feeding the growing population in a sustainable, environmentally-friendly manner will require implementation of management strategies and metabolic effectors that facilitate efficient protein deposition in livestock (Dunshea et al., 2016). Beta adrenergic receptor ligands fed to cattle improve live animal performance that translates into positive effects on muscle protein accretion and carcass parameters (Bittner et al., 2016; Bittner et al., 2017; DeClerck et al., 2020; Lockard et al., 2020). A recent review discusses the differences in the β-ligands, the receptors they interact with and the resulting tissue outcomes (Dilger et al., 2021).  相似文献   

19.
Trypanosome infection rate in cattle at Nguruman was investigated in a study conducted in 1984-1986. Shifting pastoralism significantly reduced trypanosome infections in cattle. The cattle were more heavily infected with Trypanosoma congolense (16.5%) than Trypanosoma vivax (4.95%) and Trypanosoma brucei (0.19%). Trypanosoma theileri was observed only once among the cattle examined. Mixed trypanosome infections in cattle were observed to be 2.75% and 0.014% for T. congolense/T. vivax and T. congolense/T. brucei, respectively. The duration of infection in the cattle was 55 days for T. congolense and 79 days for T. vivax. High infections in cattle were observed 2 months after the rains, which were concomitant with high tsetse densities.  相似文献   

20.
Systems approach techniques have been applied to modeling production systems for beef cattle from the relatively micro‐level of tissues and organs to the macro‐level of farms and geographical regions. This paper reviews the various types of beef cattle production models already in operation in order to analyze beef cattle production systems and their components. It may be theoretically possible to construct system models which describe such complex production systems and can be generally used in various genetic, nutritional, management and economic situations as well as in training, extension and educational programs. Moreover, the systems approach can assist in the organization of information and identification of knowledge gaps and thereby open an avenue to multi‐disciplinary research projects.  相似文献   

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