[Automatic feeding systems for horses in group housing systems with regard to animal welfare. Part 2: Comparison of different automatic feeding systems]. / Tiergerechtheit von Futterabrufstationen in der Gruppenhaltung von Pferden. Teil 2: Abrufautomaten im Vergleich.

OBJECTIVE: Comparison with regard to animal welfare of different automatic feeding systems for hay and concentrate in group housing systems for horses using parameters of ethology and physiology. MATERIAL AND METHODS: Parameters of research comprised: duration of stay, frequency of visit, threatening behaviour with and without risk of injury, and avoiding behaviour as well as heart rate and injuries of the integument. 452 horses were observed at the feeding area of 32 run-out-sheds. Every group of horses was continuously observed following the pie chart system for 24 hours. RESULTS: The "walk-through" station significantly reduced the number of conflicts in the feeding area, whereas those systems which are appropriate for the feeding horses (feeding station with access barrier and without stimulation device by electric shock) led to a higher frequency of visits and a longer duration of stay resulting in more threatening gestures. However, the number of negative interactions in the feeding area of the feeding systems can all together be classified as relatively insignificant. The heart rate was within the physiological range (45.1 ± 12.42 beats/min) in the waiting area, but increased by approximately 20 beats/min on average within the feeding station. Some horses showed a very high heart rate (≥ 100 beats/min) while entering the feeding station, possibly stress-related. There were no injuries of the integument associated with the feeding systems. The most important factor of the observation criteria was the individual group housing system with its different dimensions, conception and management. CONCLUSION: "Walk-through" stations are better than "walk-back" stations with regard to animal welfare. Likewise, automatic feeding stations with a current-carrying stimulation device are not supportive of good welfare. The other differences between the constructions of feeding stations of present systems are probably of less importance, particularly as it was shown that the stable (management, stable area, conception) had a significant influence on the surveyed parameters. Investigations to obtain information on the cause for the sporadic occurrence of very high heart rate values should be undertaken.

Maximum likelihood analysis of rare binary traits under different modes of inheritance.

Maximum likelihood methodology was applied to determine the mode of inheritance of rare binary traits with data structures typical for swine populations. The genetic models considered included a monogenic, a digenic, a polygenic, and three mixed polygenic and major gene models. The main emphasis was on the detection of major genes acting on a polygenic background. Deterministic algorithms were employed to integrate and maximize likelihoods. A simulation study was conducted to evaluate model selection and parameter estimation. Three designs were simulated that differed in the number of sires/number of dams within sires (10/10, 30/30, 100/30). Major gene effects of at least one SD of the liability were detected with satisfactory power under the mixed model of inheritance, except for the smallest design. Parameter estimates were empirically unbiased with acceptable standard errors, except for the smallest design, and allowed to distinguish clearly between the genetic models. Distributions of the likelihood ratio statistic were evaluated empirically, because asymptotic theory did not hold. For each simulation model, the Average Information Criterion was computed for all models of analysis. The model with the smallest value was chosen as the best model and was equal to the true model in almost every case studied.

Haematological changes in N'Dama and Gobra Zebu bulls during Trypanosoma congolense infection maintained under a controlled feeding regimen.

Haematological changes were monitored in Gobra-Zebu and N'Dama bulls following infection with Trypanosoma congolense. The cattle were offered a diet which provided levels of protein and energy above maintenance requirement and a pair feeding regimen was used in order to eliminate the confounding anorexic effects of trypanosomosis on the traits studied. Packed red cell volume (PCV), red blood cells (RBC) and haemoglobin (Hb) were monitored weekly. Mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), and mean corpuscular volume (MCV) were derived by computation. Significant breed differences (P < 0.001) were observed in the baseline data collected with N'Dama bulls having higher (P < 0.001) values for RBC and Hb. PCV levels were similar in both breeds pre-infection. Post-infection, there was a significant (P < 0.001) infection effect on the RBC, Hb and PCV in both breeds. The pathogenic effects were more severe in the Gobra-Zebu bulls where three out of ten bulls compared with only one out of eight infected N'Dama bulls attained the low PCV threshold, treated and withdrawn from the study along with their pair mates. Throughout the infection in N'Dama cattle and during the first 6 weeks of infection in the Gobra-Zebu bulls, the infection presented a normochromic normocytic anaemia. However, in the chronic phase, the Gobra-Zebu bulls became macrocytic. The infection reduced total dry matter intake in both breeds although this persisted longer in the Gobra-Zebus. However, their pair-fed controls showed no haematological changes indicating that the anorexia was not compounding the effects of the infection. The severity and type anaemia in N'Dama correlates with their innate ability to resist the effects of trypanosome infection compared to the Gobra-Zebu bulls.

Effect of strategic gastrointestinal nematode control on growth of N'Dama cattle in Gambia.

From October 1989 to December 1994, a longitudinal study on the control of gastrointestinal nematodes was done on 1000 N'Dama cattle in 20 private herds in Gambia. Each herd was divided into two groups with an even distribution of age and sex. One group received a single anthelmintic treatment of Fenbendazole, Panacur Hoechst Veterinär GmbH, 7.5 mg kg-1 BW in October 1989, whereas the other group served as an untreated control. In July 1990, the herds were subdivided into two different treatment schemes. In the herds of the first scheme the treated animals (Treatment group I) were treated once (in August), whereas in the herds of the second scheme the treated animals (Treatment group II) were treated twice (in July and September). The same treatment schedule was used in the subsequent rainy seasons until December 1994. One group in every herd served as control (Treatment group 0) and received no anthelmintic treatment throughout the study. One annual fenbendazole treatment had no significant effect on liveweights, whereas two annual treatments significantly increased liveweights of the age group 12-24 and 24-36 months by 9.4%, and 17.5%, respectively. Animals less than 12 months old had 6.3% higher liveweights after two treatments, the difference was statistically not significant (P < 0.06). Average weights of 3- and 4-year-old, twice-treated animals were 13.1% and 8.2%, respectively, higher compared with their controls. No effect of anthelminthic treatment on liveweights was found in 5-year-old and older animals. Herd structure analysis demonstrated that overall male offtake rates ranged from 12 to 28% in the 3-, 4- and 5-year-old age categories. The age categories within which deworming improves liveweights thus coincides with the age at which males are mainly sold. These results suggest that biannual metaphylactic treatments (end of July and beginning of September) of all animals from birth to an age of 4 years should be recommended, provided that the financial analysis demonstrates the profitability of this intervention.

Recent acquisitions on tick and tick-borne disease resistance in N'dama (Bos taurus) and Gobra zebu (Bos indicus) cattle.

The use of disease resistant breeds is recognised as an economically realistic alternative to acaricide application and drug administration in tick and tick-borne disease control schemes. Although resistance is mainly associated with zebu (Bos indicus) breeds, studies carried out in The Gambia show a higher resistance to ticks and tick-borne diseases in N'dama (Bos taurus) than in Gobra (B. indicus) cattle. Tick resistance in N'dama breed appears to be effective against those species with long hypostome, such as Amblyomma variegatum and Hyalomma spp. The possible mechanisms involved are discussed. Further investigations are identified to assess the economic value of tick and tick-borne disease resistance in the N'dama breed.

Ownership pattern and management practices of small ruminants in The Gambia - implications for a breeding programme.

In the framework of a genetic improvement scheme a countrywide survey of small ruminant owners was conducted in The Gambia to obtain information about the ownership pattern, reasons for keeping and especially about breeding and management practices including housing and feeding. The main results were the following: women play a major role in small ruminant production, representing 52% of the owners of sheep, 67% of the owners of goats and 43% of the owners of both sheep and goats. The average number of animals owned is quite low (about six head of sheep and goats each, out of which about three are breeding females). Most of the breeding males are born in their respective flock and there are fewer breeding bucks than breeding rams. However, there are sufficient numbers of breeding males around. Animals are mainly left free to roam around during the dry season, and are either tethered or herded in the rainy season. During night animals are housed or tied under a shelter. Supplementary feeding is not common and vaccination against Pest des Petit Ruminants (PPR) and Pasteurellosis is only partly carried out. Implications for the establishment and structure of a multiplication tier within a three tier breeding scheme, nucleus-->multipliers-->farmers are discussed.

Milk production of West African Dwarf goats in the Gambia.

Goats are important in the low-input systems of West Africa and their main importance lies in their role for income and saving. In addition, it is known that milk offtake for home consumption is also important. In order to obtain information about the real importance of milk offtake, a recording scheme was operated in 27 villages in the Central River Division of The Gambia from July 1998 until January 2000. Detailed information was obtained from about 1500 kiddings. In the recording scheme, any sheep being milked as well as the goats of the International Trypanotolerance Centre nucleus flock were also recorded. In the villages, 36% of all lactations were used for milk offtake, but the fraction milked was lower for the first two lactations. The average length of lactation was 127 days and the average daily milk offtake was 0.18 L. Goats are milked once a day and the residual milk is left for the kids. Milking starts about one week after parturition and stops when the goat becomes pregnant or the kid(s) die or the goat is drying off. The repeatability of the 90-day milk offtake was 0.24 +/- 0.09. Sixty-five percent of goat owner were women and a large fraction of goat owners also owned cattle. Goat milk was used exclusively for home consumption. It is concluded that in breeding and extension work more attention should be given to aspects of milk production.

Investigations on functional traits in Simmental: 1. Treatment costs for ten different diseases.

SUMMARY: All health-related events and treatment costs (by veterinarian and non-veterinarian) were recorded through fortnightly interviews with the herdsmen of 104 Simmental dairy farms in Upper Bavaria from autumn 1987 to spring 1990. The data include 8381 calvings and the subsequent time period. For ten different disease-classes the sum of all treatment costs from calving up to either the subsequent calving or up to culling were computed. A multiplicative model with three covariates was fitted to these observations. The covariates are farm, parity and type of end of lactation (culling or subsequent calving). Farm effects are significant for almost all diseases. The average sum of treatment costs per calving with an associated disease was estimated as the average expected value for this sum, where averaging is over the farms. These costs range from 29 DM (claw disorders) up to 137 DM (dystocia). The average costs per calving (with or without disease) range from 1.59 DM (injuries of the udder) to 10.90 DM (fertility problems). Corresponding costs per cow and year are 1.74 DM and 12.24 DM. ZUSAMMENFASSUNG: Auf 104 Fleckviehbetrieben wurden insgesamt 8381 Kalbungen, alle auf diese Kalbungen folgenden Erkrankungen und die zugehörigen Behandlungskosten erhoben. Für zehn verschiedene Erkrankungsarten wurden jeweils alle Behandlungskosten innerhalb einer Zwischenkalbezit aufsummiert. An diese Beobachtungswerte wurde jeweils ein multiplikatives Modell mit den Einflußfaktoren Betrieb, Laktationsnumner und Art der Zwischenkalbezeit (beendet durch Kalbung bzw. durch Abgang) angepßt. Im Gegensatz zu den beiden anderen Faktoren erweist sich der Betrieb bei fast allen Erkrankungsarten als signifikant. Die durchschnittlichen Kosten innerhalb einer betroffenen Zwischenkalbezeit wurden als durchschnittlicher Erwartungswert über alle Betriebe berechnet. Diese Kosten liegen je nach Erkrankungsart in einem Bereich, der von ca. 29 DM (Klauenerkrankungen) bis zu ca. 137 DM (Schwergeburt) reicht. Umgerechnet auf eine beliebige Kalbung (mit oder ohne folgende Erkrankung) entstehen Kosten zwischen 1,59 DM (Euterverletzungen) und 10,90 DM (Fruchtbarkeitsprobleme). Je Kuh und Jahr betragen die entsprechenden Werte 1,74 DM und 12,24 DM.

Ownership pattern and management practices of cattle herds in the Gambia: implications for a breeding programme.

A questionnaire and a census were carried out in 1998/99 on 201 cattle herds in 44 villages located in three different areas of The Gambia, in order to obtain information about the ownership pattern, management and breeding practices for optimizing and extending a pure breeding scheme for indigenous N'Dama cattle. The herds had an average of 58.5 head, of which 39.3% were cows, and most of them were multiowner herds, having on average 5.5 owners. Overall, women represented 38.3% of the owners, but they owned only 15.9% of the cattle. Some of the senior herdsmen received no payment, as they were family members, but most of them received payment in kind, i.e. milk off-take from the herd. Payment in cash only or cash as well as milk was rare. In larger herds it was quite common for additional herdsmen to be hired throughout the year, their payment shifting towards cash only or cash and milk. Many small herds had no older bulls or breeding bull and almost all breeding bulls were born within the herd. In most cases, it was the herd owner who was responsible for the selection of the breeding bull. Traits related to the growth and milk production of the dam were considered as most important for a good breeding bull. The results are discussed with respect to the extension of a pure breeding scheme for N'Dama cattle.