The economic importance of dystocia in dairy cattle and the development of an ordered categorical analysis procedure to evaluate sires for calving ease

From May 1981 through January 1984, data were collected on 555,562 Holstein cows in the DHI program. The objectives of this study were: (1) to determine the completeness of reporting of dystocia, (2) to determine the economic influence of dystocia by age of cow on 305-day mature equivalent (ME) milk and milk fat production, days open and days dry, and (3) to implement the ordered categorical analysis procedure and to determine whether this method ranks sires differently than the method currently used by the NAAB;Thirty-four percent of the cows had dystocia scores reported. Data prior to June 1982 were not used because of inconsistent reporting of dystocia data leaving a total of 141,655 lactations with dystocia information;Days opens in first parity were 14 days greater for births scored 5 versus 1. The differences were larger in later parities. There were 26 more days open in second parity and 19 more days open in third and greater parities for score 5 versus 1;Differences between cows with score 5 and cows with score 1 were 465 kg ME milk and 20.7 kg ME fat less in first lactation, 576 kg ME milk and 20.9 kg Me fat less in second lactation and 725 kg ME milk and 25.0 kg fat less in third and greater lactations, with cows producing more in lactations following an easy birth;Sires with 5 progeny and herd-year-seasons having more than 14 sires were used to have a data set useful to estimate variance components. A total of 223 HYS and 189 sires were used for the standardized threshold model without relationships. The heritability estimate of the underlying continuous trait was .148. When relationships among sires were added the number of sires increased to 225 and the h(\u272) estimate became .147. Herd-year-season variance accounts for 13% of the total variance;Compared to the current national calving ease sire evaluation program the proposed threshold model compensates for two violations of major assumptions: (1) additivity of effects, and (2) homogeneity of variances. It allows computation of the Expected Percent Difficult First Calvings (4 or 5). Rank correlations among sire solutions were 76% and 79% without relationships and with relationships, respectively. Both approaches tend to agree on the most difficult sires

Identification of the behavioral criteria of dairy cattle on the basis of electronic imaging

The paper deals with the identification of the behavioral criteria of dairy cattle through Imaging. The objective of the study is the optimization of the rate of pregnancy in these cows. Indeed, the gestural behaviors of 200 cows belonging to a stable were observed by giving more attention to cows that show signs of heat known. A camera was used to record the different postures and the different behaviors of these cows. The quantitative data of reproduction studied farm showed that the rate of pregnancy in these cows is far from optimal. This is due essentially to a lack of monitoring and observation of cows in heat negatively affecting the economics of the operation. Detecting cows in heat can be made and improved by using Imaging. This will facilitate the life of farmers and increase their income and decreasing the time for detection of the heat

Tunisian reservoirs : diagnosis and biological potentialities

International audienc

Tunisian reservoirs: diagnosis and biological potentialities

Due to scarcity, irregular rainfall and increasing water demand, several reservoirs have been built in recent decades in Tunisia to meet water needs for essential uses, which is generally done without analysis of their capacity to maintain a high quality of aquatic life and equitable distribution of water resources. Currently, 90% of available water resources are already mobilized and climate change exacerbates the country's aridity which makes it difficult to monitor water needs. With a view to contributing to their effective management and setting future directions for controlling and improving inland fish productivity, a comparative limnological study was carried out on 8 artificial reservoirs that were stocked with mullet fry. This study, based on a review of existing data, provides information on the availability and quality of inland water resources in relation to international standards and the biological potential (plankton, fish and other organisms) of these reservoirs. The satisfactory water quality for aquatic life, as well as the significant growth and production of introduced species associated with the rearing of mullet fry, clearly show that, despite several problems, Tunisian reservoirs represent an important potential that still needs to be developed. To this end, we recommend to improve the fishing techniques and the stocking of mullet fry. In addition, the strengthening of fishermen's groups, the encouragement of private initiative and the quality control of water and fish meat are highly requested

Saving threatened native breeds by autonomous production, involvement of farmers organization, research and policy makers: The case of the Sicilo-Sarde breed in Tunisia, North Africa

The Sicilo-Sarde, the only native milking sheep in Tunisia and in North Africa has undergone a considerably population reduction from 200,000 ewes in 1995 to 25,000 ewes in the year 2000. Low sheep milk price and a shift to dairy cattle were among the reasons for this decline. The train objective of this study was to report on the impact of farmers organization, technology transfer and market on reversing the dramatic decline of this native dairy sheep breed to a promising livestock development model. Having at the grassroots a pioneer who chose to form the Sicilo-Sarde breed association in 2003 was a key ingredient in the process of saving this breed from disappearance. Quick steps were first taken: Selling milk through the association allowed doubling its price in one year. A new legislation benefiting dairy sheep was introduced. A trilogy principle was followed where breed owners, researchers and policy makers interacted together to find optimum solutions that fit expressed needs of breed owners. An applied multidisciplinary research program was established and tackled major constraints faced by the breed in nutrition, management, reproduction, health, breeding and product development. Encouraged by an unsatisfied market and good prices, small farmers with a few cows started shifting to dairy sheep and poor new ones managed to get loans to purchase dairy sheep breeding animals. Based on a total of 7937 lactations recorded during the period 1997-2002, average milk yield, days in milk and suckling period were 89 kg +/- 47 kg, 139 d +/- 47 d and 104 d +/- 22 d, respectively. Given the low producing ability of the breed and the impossibility of importing proven rams for health considerations, frozen semen from 17 Sarda rams was imported from Italy and 1600 ewes from 12 flocks were inseminated by intrauterine in 2005-2006. Fertility, prolificacy, and mortality rates varied from 47% to 63%, 157% to 184% and 0 to 34%, respectively. The decline of the breed was stopped and reversed and members of the association and small farmers in the region will benefit from the produced offspring. While currently the association is accessed by more organized producers, it provides an opportunity for the integration of smaller, poorer producers to improve their livelihoods. This case has inspired another group of farmers of a native sheep meat breed to form their own association to promote their breed. (C) 2008 Elsevier B.V. All rights reserved

Stock assessment of freshwater fish in Tunisian reservoirs: analytical and acoustical approaches.

La pêche dans les eaux douces est une activité relativement récente en Tunisie. Elle n’a connu un essor important que dans les années 90 à la suite du projet de coopération Tuniso-allemand de la Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ). Les retenues de barrages tunisiens constituent des macrocosmes dont l’équilibre halieutique peut être perturbé par l’introduction de nouvelles espèces ou par l’activité anthropique notamment la pêche. L’objectif de ce travail est de quantifier les biomasses spécifiques exploitées dans les plans d’eaux douces tunisiens afin de donner leurs états d’exploitation. Pour ce faire, deux méthodes ont été utilisées : la modélisation analytique et l’hydro¬acoustique. La modélisation analytique et plus particulièrement l’Analyse Virtuelle des Populations (VPA), est un procédé qui est couramment utilisé dans l’analyse des stocks de poissons exploités en mer mais qui a comme inconvénient, de nécessiter, un nombre considérable de paramètres de production et de croissance. Les résultats obtenus ont, cependant, l’avantage d’être très puissants et permettent de donner des recommandations afin d’exploiter de façon optimale la ressource halieutique. L’évaluation de stock dans les plans d’eaux douces en Tunisie par écho¬prospection constitue une première. La retenue du barrage de Sidi-Salem a été choisie comme site pilote afin de mettre au point la méthodologie. L’étude du comportement piscicole dans la retenue a permis de favoriser le comptage de cibles individuelles à l’écho intégration. La biomasse exploitable de deux poissons, le rotengle Scardinius erythrophtalmus et le gardon Rutilus rubilio a été déterminée. Celle du rotengle Scardinius erythrophtalmus dans la retenue de Sidi-Salem a été estimée à 112,4 T. Ce stock est légèrement sur-exploité. Il ne faudrait utiliser que 75 % de l’effort de pêche actuel afin d’atteindre le rendement par recrue optimal évalué à 59,5 g. Ces résultats ont été obtenus en supposant que la mortalité naturelle soit constante quelque soit l’âge du poisson. La biomasse exploitable du gardon Rutilus rubilio dans la retenue de Sidi-Salem a été estimée à 47,7 T. Ce stock est exploité de façon optimale (Y/R = 63,5 g). L’écho prospection a permis d’évaluer la biomasse instantanée toutes espèces confondues dans la retenue du barrage de Sidi-Salem à 192,4 T, soit des biomasses respectives pour le sandre, le mulet, le silure, la carpe, le gardon et le rotengle de 75 T, 7,7 T, 1,9 T, 3,9 T, 11,5 T et 92,3 T. Dans la retenue du barrage de Bir-Mcherga, la biomasse totale a été évaluée a 310,7 T, alors que la biomasse spécifique de la carpe, du mulet, du barbeau et de la phoxinelle a été estimée respectivement à 189,5 T, 68,4 T, 49,7 et 3,1 T. En prenant comme référence le résultat d’évaluation du stock exploitable du gardon et du rotengle cumulé, l’hydro-acoustique a tendance à sous-évaluer cette biomasse.Fishing in the Tunisian freshwaters is a relatively recent activity. It knew an important rise in the nineties following the Tuniso-German cooperation project of the Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ). Reserves of Tunisian dams constitute macrocosms whose fish balance can be disturbed by the introduction of new species or anthropic activity in particular fishing. The main purpose of this work is to quantify the specific biomasses exploited in the Tunisian freshwater reserves in order to give their states of exploitation. With this intention, two methods were used: analytical modelling and hydro-acoustic. Analytical modelling and more particularly the Virtual Populations Analysis (VPA), is a process which is usually used for the analysis of the exploited fish stocks at sea, but which has the disadvantage, to require, a considerable number of parameters of production and growth. However, the results obtained have, the advantage to be very powerful and make it possible to give recommendations to fish in an optimal way the resource. The stock assessment in the Tunisian freshwater by hydro acoustic constitutes a first. The reserve of the Sidi-Salem dam was selected like a control site in order to develop methodology. The study of the piscicultural behaviour in reserve made it possible to support the counting of individual targets at echo integration. The exploitable biomass of two fishes, the rudd Scardinius erythrophtalmus and the roach Rutilus rubilio were given. The exploitable biomass of the rudd Scardinius erythrophtalmus in the reservoir of Sidi-Salem was estimated at 112.4 T. This stock is slightly overexploited. we would not have to use more than 75 % of the current fishing effort to reach the optimal yield by recruit evaluated at 59.5 g. These results were obtained by supposing that the natural mortality was constant independently to the age of the fish. The exploitable biomass of the roach Rutilus rubilio in the reserve of Sidi-Salem was estimated at 47.7 T. This stock is exploited in an optimal way (Y/R = 63.5 g). Hydro acoustic allowed to quantify the instantaneous biomass all species confused in the reserve of Sidi-Salem dam was 192.4 T. That is to say a respective biomasses for pikeperch, mullet, catfish, carp, roach and the rudd of 75, 7.7, 1.9, 3.9 , 11.5 and 92.3 T. In the reserve of the Bir-Mcherga dam, the total biomass was evaluated at 310.7 t, whereas the specific biomass of carp, mullet, barbel and minnow was estimated at 189.5, 68.4, 49.7 and 3.1 T respectively. By taking as reference the exploitable stock assessment of the cumulated roach and rudd, hydro-acoustics methods tends to underestimate the biomass.Unpublishe

The economic importance of dystocia in dairy cattle and the development of an ordered categorical analysis procedure to evaluate sires for calving ease

From May 1981 through January 1984, data were collected on 555,562 Holstein cows in the DHI program. The objectives of this study were: (1) to determine the completeness of reporting of dystocia, (2) to determine the economic influence of dystocia by age of cow on 305-day mature equivalent (ME) milk and milk fat production, days open and days dry, and (3) to implement the ordered categorical analysis procedure and to determine whether this method ranks sires differently than the method currently used by the NAAB;Thirty-four percent of the cows had dystocia scores reported. Data prior to June 1982 were not used because of inconsistent reporting of dystocia data leaving a total of 141,655 lactations with dystocia information;Days opens in first parity were 14 days greater for births scored 5 versus 1. The differences were larger in later parities. There were 26 more days open in second parity and 19 more days open in third and greater parities for score 5 versus 1;Differences between cows with score 5 and cows with score 1 were 465 kg ME milk and 20.7 kg ME fat less in first lactation, 576 kg ME milk and 20.9 kg Me fat less in second lactation and 725 kg ME milk and 25.0 kg fat less in third and greater lactations, with cows producing more in lactations following an easy birth;Sires with 5 progeny and herd-year-seasons having more than 14 sires were used to have a data set useful to estimate variance components. A total of 223 HYS and 189 sires were used for the standardized threshold model without relationships. The heritability estimate of the underlying continuous trait was .148. When relationships among sires were added the number of sires increased to 225 and the h('2) estimate became .147. Herd-year-season variance accounts for 13% of the total variance;Compared to the current national calving ease sire evaluation program the proposed threshold model compensates for two violations of major assumptions: (1) additivity of effects, and (2) homogeneity of variances. It allows computation of the Expected Percent Difficult First Calvings (4 or 5). Rank correlations among sire solutions were 76% and 79% without relationships and with relationships, respectively. Both approaches tend to agree on the most difficult sires.</p