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PubMed1998

Breed and season effects on the peri-parturient rise in nematode egg output in indigenous ewes in a cool tropical environment.

A study was carried out at the International Livestock Research Institute (ILRI) Debre Berhan Research Station in Ethiopia from 1992 to 1995 to compare the peri-parturient rise (PPR) in faecal nematode egg counts (FEC) in ewes of two indigenous sheep breeds. A total of 1439 Menz and 1347 Horro ewes were single sire mated following oestrus synchronization to lamb in the wet and dry season. Three ewe treatment groups were constituted as mated/lactating/undrenched; mated/lactating/drenched; unmated/undrenched for three wet and three dry lambing seasons. All ewes grazed naturally contaminated pasture. Levels of faecal egg output were monitored at mating, 3 months after mating, 2 weeks before lambing, 4, 8 and 12 weeks post-lambing. A significant PPR in FEC occurred 2 weeks before lambing and peaked at 4 weeks post-parturition in ewes lambing just before the beginning of the dry season (October/November). There was no significant increase in FEC when lambing occurred before the onset of the long rainy season (May/June). The PPR in this study was associated with both lactation and seasonal availability of third-stage infective larvae on pasture. There was no consistent breed difference in FEC during the six sampling periods from mating to weaning. Faecal cultures and worm counts from both breeds confirmed the presence of Longistrongylus (Pseudomarshallagia) elongata, Trichostrongylus spp.and Haemonchus contortus. The role of the peri-parturient rise of FEC in ewes in gastrointestinal nematode transmission is discussed.

Animals↗

PubMed1998

Susceptibility to trypanosomosis of three Bos indicus cattle breeds in areas of differing tsetse fly challenge.

Studies to assess the differences in susceptibility to trypanosomosis among Bos indicus cattle breeds (Maasai Zebu, Orma Boran and Galana Boran) were conducted under conditions of varying tsetse fly challenge at the Nguruman escarpment in south-western Kenya, for a period of 1 year. It was found that under tsetse challenge quantified as high, Maasai Zebu and Orma Boran were less susceptible than Galana Boran to trypanosome infections, as judged by the significantly lower incidence of infection, development of less severe anaemia, fewer requirements for trypanocidal drug treatments, higher growth rates and fewer mortalities. In the area where tsetse challenge was considered low as a result of a tsetse fly control operation using odour-baited traps, only the Maasai Zebu and Orma Boran were compared. No significant differences in the incidence of infection, degree of anaemia or growth rates were observed between the two breeds, but all were significantly different from their counterparts in the high tsetse challenge area. These results suggest that there is variation in resistance to trypanosomosis among Bos indicus cattle breeds that could be exploited as part of the integrated trypanosomosis control programmes in East Africa.

Anemia↗

PubMed2002

Influence of classification levels of ram sexual activity on spring breeding ewes.

Ram lambs (7-8 months old) and mature rams (19-20 months old) were used to evaluate the effect of classification levels of male sexual performance on reproductive performance of ewes during spring breeding. In Exp. 1, sexually active ram lambs with high (1.8+/-0.3; n=5) and low (0.9+/-0.2; n=5) sexual performance scores (HP and LP; mean+/-S.E.M.) were used in single sire breeding pens. Ewes (n=305) were stratified by age and assigned to 10 pens for 34 days starting in late March. For Exps. 2 and 3, two replicates were conducted for 2 years with sexually active mature rams in a single sire mating scheme. For Exp. 2, HP rams (n=5) averaged 3.6+/-0.2 ejaculations and LP rams (n=7) 1.8+/-0.2 ejaculations for sexual performance scores based on nine, 30 min serving capacity tests (SCT). Polypay ewes (n=152 to 153 per year) were stratified by age and assigned to pens each year for 34-38 days starting in late March for years 1 and 2. For Exp. 3, HP rams (n=6) averaged 3.7+/-0.1 ejaculations and LP rams (n=10) 2.3+/-0.1 ejaculations for sexual performance scores based on 18, 30 min SCT. Polypay ewes (n=229 in year 3 and n=244 in year 4) were stratified by age and assigned to pens each year for 34 days starting in late March. In Exp. 1, lambing rates for ewes bred to HP versus LP ram lambs did not differ (65.8 versus 53.0; P=0.20). Prolificacy tended (P=0.06) to be increased by 0.1 lambs in ewes bred by LP ram lambs. Total number of lambs born per ewe present at lambing, and lambing distribution were not altered by HP and LP ram lambs. In Exp. 2, lambing rates for fall-lambing ewes bred to mature HP or LP rams did not differ (58.1 versus 60.1; P=0.78). In Exp. 3, lambing rates for fall-lambing ewes bred to mature HP or LP rams did not differ (74.3 versus 69.0; P=0.35). There was no difference (P>0.10) between years for Exp. 2 or Exp. 3, and mature HP and LP rams did not affect the other reproductive variables monitored. Analyses of the combined data for Exps. 2 and 3 indicated only a year difference (P<0.001) in lambing rates and total lambs born. Present studies indicate that different sexual performance classifications for ram lambs and mature rams did not alter lambing rates or distribution of lambing of Polypays bred in late March to April. These results indicate that HP and LP, sexually active, Polypay rams and ram lambs with average to high quality semen can provide a source of rams for spring breeding Polypays in ambient conditions and that there was no advantage to using HP over sexually active LP ram lambs or rams.

Aging↗

PubMed1992

Management of replacement breeding animals.

In conclusion, replacement gilts should be finally selected before 110 kg body weight and should have been stimulated to reach puberty by this time. Currently, the best method for achieving this is ad libitum feeding and the correct use of boar exposure. However, whether ad libitum feeding will always be the best feeding strategy remains to be seen. The impressive success of selection programs and the potential for the use of growth promoters and repartitioning agents in the feeder barn may require that future replacements be identified at an early stage and raised under a separate feeding regimen. To produce a large first litter, gilts should be bred at their second estrus. There is unlikely to be any further increase in litter size by delaying mating to third estrus. A major consideration when choosing when to breed replacements is the length of their productive life. For many farms, this may be maximized by delaying breeding until the sow is 120 to 130 kg body weight with a minimum backfat depth of 18 mm. For the producer who is able to exert control over lactation condition loss, however, breeding replacements at about 110 kg body weight with backfat depths of 14 to 16 mm should not adversely affect long-term performance. Although it is true that, under some conditions, the lean gilt may become a problem, it is equally true that her potential is as great as her fatter contemporaries. Whether this potential is realized is largely under the producer's control. Regarding the boar, nutritional management need not vary from that provided for gilts. However, if replacement boars are raised on-farm, it is of great importance that they be allowed to socially interact with other pigs. Failure to provide this opportunity will result in a boar with reduced libido.

Animal Husbandry↗

PubMed1992

Training the novice stallion for artificial breeding.

Although the act of breeding is instinctive to the stallion, the use of a phantom mare and AV represent an unnatural element to this act. The use of these devices, as well as proper breeding manners and etiquette, must be taught to the stallion. The novice stallion usually learns these techniques rapidly and is quite manageable if proper restraint is used during training. Positive reinforcement for good behavior is essential. The ultimate goal in training the novice stallion is to develop an individual that will enter the breeding area with controlled enthusiasm, develop an erection and gracefully mount the phantom or mare in a quiet manner, and rapidly ejaculate into an AV.

Animals↗

PubMed2002

Breed differences in growth hormone and insulin secretion between lactating Japanese Black cows (beef type) and Holstein cows (dairy type).

This study was performed to clarify the levels of growth hormone (GH) and insulin (INS) secretions and the glucose response to INS during lactation in a representative beef breed in Japan, Japanese Black cows, and to compare them with their counterparts in a dairy breed, Holstein cows. Six Japanese Black and seven Holstein primiparous cows received a single intravenous injection of GH-releasing factor (GRF; 0.25 microg/kg), glucose (112.5 mg/kg), or INS (0.2 U/kg) from late pregnancy (2 weeks antepartum) to mid-lactation (6 months postpartum). Japanese Black cows had one-tenth of the total milk yield of Holstein cows during lactation, and significantly lower GRF-induced GH and higher glucose-induced INS secretions than Holstein cows at all stages. In Japanese Black cows, even with lactation, these secretions remained essentially unchanged, whilst Holstein cows showed higher GH and lower INS secretions after the onset of lactation as compared with cows in late pregnancy. Both breeds had similar glucose response to INS at the respective stages. These results suggest that, during lactation, Japanese Black cows may minimize the catabolic effects of GH and sustain the anabolic effects of INS, in contrast with Holstein cows, but have similar ability to inhibit INS-mediated glucose utilization in peripheral tissues to Holstein cows.

Animals↗

PubMed1999

Comparative parasitological and haematological changes in two breeds of sheep infected with Fasciola gigantica.

Twelve each of Red Masai and Dorper sheep, aged between 6 and 9 months, were acquired from a Fasciola-free area of eastern Kenya. Each breed was divided into two groups of 6. The sheep in one group of each breed were experimentally infected with 400 viable metacercariae of Fasciola gigantica. The other group of 6 sheep of each breed remained as uninfected controls. The animals were monitored regularly for any evidence of disease. Blood samples taken weekly revealed a general reduction in red cell counts and packed cell volume, which was much faster in the infected Dorper sheep than in the Red Masai. This reduction started from the tenth week after infection and persisted to the end of the experiment 18 weeks post infection (PI). The absolute eosinophil counts rose in all the infected animals, but the values were higher among the Dorper than among the Red Masai. Patency occurred at weeks 12 and 13 PI in the Red Masai and Dorpers, respectively, with the latter shedding significantly more fluke eggs. The worm recovery rates were higher among the Dorpers than among the Red Masai, though not significantly so. On the basis of egg counts and clinicopathology, the Dorper sheep were considered to be more susceptible to F. gigantica infections.

Animals↗

PubMed2002

Harnessing heredity in Gilded Age America: middle class mores and industrial breeding in a cultural context.

By investigating the practices and beliefs of Gilded Age trotting horse breeders, this article demonstrates the relationship between industrial economic development and the growth of genetic reasoning in the United States. As most historians of biology already know, E. H. Harriman, Leland Stanford, and John D. Rockefeller not only transformed American business practice, they donated heavily to institutions that promoted eugenic research programs. What is not widely known, however, is that these same industrialists were accomplished trotting horse breeders with well-developed theories of inheritance. The article that follows uses these theories to place the rise of eugenic and genetic research into the context of the rapid development of industry in post Civil War America. Specifically, the study identifies how functional utility as defined through the narrow concerns of industrial practices were privileged over form and pedigree in American horse breeding. Even more importantly, this article suggests that the continuity established between the practices of the industrial philanthropists and the scientific research institutions that they established occurred at two levels: through the values privileged by the development of the dynamics of a mass society and through the tools used to process the large amounts of information necessary to understand breeding patterns in slow breeding organisms.

Animals↗

PubMed2001

Cancer risk in the reindeer breeding Saami population of Sweden, 1961-1997.

The Saami people are the natives of northern Scandinavia and the Kola Peninsula. In a cohort of 2033 Swedish reindeer breeding Saamis, the cancer risks between 1961 and 1997 were studied. In total, 193 cases of cancer were observed versus 322 expected in the general Swedish population and 249 in a geographically matched reference population of non-Saamis. In comparison to non-Saamis living in the same area, the reindeer breeding Saamis showed a statistically significant lower risk of developing cancer of the prostate and of malignant lymphoma, whereas the risk of stomach cancer was significantly higher. Although there were no statistically significant changes of cancer risks over time, temporal trends were indicated towards a decreased risk of cancer in the stomach and the prostate. The results suggest that the explanations of the low cancer risk of the reindeer breeding Saamis, in relation to the non-Saamis in the same environment, are to be found among lifestyle and/or genetic factors.

Age Distribution↗

PubMed1997

More efficient breeding systems for controlling inbreeding and effective size in animal populations.

A selection scheme and a mating scheme are proposed to control the inbreeding and genetic drift in conserved or control animal populations with different numbers of males and females. Recurrence equations for the inbreeding coefficient and formulae for effective size are derived for autosomal loci, sex-linked loci with males being heterogametic and sex-linked loci with females being heterogametic under each of four breeding systems. It is shown that both the selection scheme and the mating scheme proposed in this paper could increase the effective size and decrease inbreeding in any generation compared with the classical selection and mating schemes. Among the four breeding systems considered, the most efficient one could increase the effective size by as much as 19 per cent for autosomal loci and 50 per cent for sex-linked loci in comparison with the classical breeding system usually utilized in conserved or control populations.

Animals↗

PubMed1996

Transgenic Indica rice breeding line IR58 expressing a synthetic cryIA(b) gene from Bacillus thuringiensis provides effective insect pest control.

The Indica rice breeding line IR58 was transformed by particle bombardment with a truncated version of a synthetic cryIA(b) gene from Bacillus thuringiensis. This gene is expressed under control of the CaMV 35S promoter and allows efficient production of the lepidopteran specific delta-endotoxin. R0, R1 and R2 generation plants displayed a significant insecticidal effect on several lepidopterous insect pests. Feeding studies showed mortality rates of up to 100% for two of the most destructive insect pests of rice in Asia, the yellow stem borer (Scirpophaga incertulas) and the striped stem borer (Chilo suppressalis), and feeding inhibition of the two leaffolder species Cnaphalocrocis medinalis and Marasmia patnalis. Introduction of stem borer resistance into the germplasm of an Indica rice breeding line now makes this agronomically important trait available for conventional rice breeding programs.

Animals↗

PubMed2026

High quality genome assemblies of African cattle breeds using PacBio HiFi sequencing.

Africa has a uniquely rich cattle diversity of ~150 breeds comprising the Bos taurus indicus sub-species, Bos taurus taurus, and their crosses. These represent ~23% of the global cattle population. However, high quality, representative assemblies are limited for African cattle and especially for indicine breeds. Here we built high quality de novo assemblies for five important African indigenous cattle breeds using PacBio HiFi sequencing: Lagune (Bos taurus taurus), Gudali, Iringa Red and Singida White (Bos taurus indicus), and Mpwapwa (Bos taurus taurus x Bos taurus indicus). These new assemblies are the most contiguous and complete African cattle assemblies produced so far, with genome sizes of 3.25-3.36 Gb, contiguity N50s ranging from 83.59 Mb to 97.87 Mb and scaffold N50s from 100.30 Mb to 113.37 Mb. BUSCO genome completeness scores were also higher than 99.68%, indicative of highly contiguous assemblies. These improved and highly contiguous genome assemblies are consequently a valuable resource for future African and global livestock genomic studies.

Animals↗

PubMed2003

Chromosomal inversions effect body size and shape in different breeding resources in Drosophila buzzatii.

The cactophilic Drosophila buzzatii provides an excellent model for the study of reaction norms across discrete environments because it breeds on rotting tissues (rots) of very different cactus species. Here we test the possible effects of second chromosome inversions on body size and shape (wing loading) across suitable natural breeding substrates. Using homokaryotypic stocks derived from several lines homozygous for four naturally occurring chromosomal inversions, we show that arrangements significantly affect size-related traits and wing loading. In addition, karyotypes show differing effects, across natural breeding resources, for wing loading. The 2st and 2jz(3) arrangements decrease and the 2j arrangement increases wing loading. For thorax length and wing loading, karyotypic correlations across host plants are slightly lower in females than in males. These results support the hypothesis that these traits have a genetic basis associated with the inversion polymorphism.

Animals↗

PubMed2002

Exploring the potential of life-history key innovation: brook breeding in the radiation of the Malagasy treefrog genus Boophis.

The treefrog genus Boophis is one of the most species-rich endemic amphibian groups of Madagascar. It consists of species specialized to breeding in brooks (48 species) and ponds (10 species). We reconstructed the phylogeny of Boophis using 16S ribosomal DNA sequences (558 bp) from 27 species. Brook-breeders were monophyletic and probably derived from an ancestral pond-breeding lineage. Pond-breeders were paraphyletic. The disparity in diversification among pond-breeders and brook-breeders was notable among endemic Malagasy frogs, although it was not significant when considering Boophis alone. Sibling species which have different advertisement calls but are virtually indistinguishable by morphology were common among brook-breeders; genetic divergence between these species was high (modal 8% total pairwise divergence). Substitution rates in brook-breeding species were significantly higher than in pond-breeders. Speciation of pond-breeders may be hindered by their usually more synchronous reproduction and a higher vagility which enhances gene flow, while a higher potential of spatial segregation and speciation may exist along brooks.

Animals↗

PubMed1997

Hyalomma ticks: bovine resistance under field conditions as related to host age and breed.

Field collection of ticks from two breeds of cattle [Native breed (local) and purebred [Friesian)], showed that the number of ticks was higher on purebred than on native cattle. The susceptibility seemed to increase with the age of the animals. Furthermore, breed appeared to exert more influence than age. There was no correlation between the number of ticks associated with each animal, the antibody production and antigens recognized. The immune response under field condition looked more like immune suppression than immune protection.

Aging↗

PubMedDate not supplied

Effect of dietary supplementation of fatty acids and vitamins on the breeding performance of the carp Catla catla.

Five isonitrogenous diets (approximately 33% crude protein) were fed to the brood female carp, Catla catla (weighing 3.0 to 5.5 kg), for a period of 93 days in order to observe their breeding performance in earthen ponds. Diet-I (control) contained only basic ingredients like rice bran, ground-nut oil cake, roasted soybean meal, fish meal and mineral mixture; diet-II contained added vitamins; diet-III contained added vitamins and vegetable oil (rich in n-6 polyunsaturated fatty acids, PUFA); diet-IV contained added vitamins and fish oil (rich in n-3 PUFA); and diet-V contained added vitamins and a mixture of vegetable and fish oils. The results showed that nutritional quality of the diet considerably influenced breeding performance in the species. The total number of matured females was the highest in the diet-V group and maturity was advanced by 35 days in this group compared to the control. In diet-III and diet-V groups, all the maturated females bred fully and the relative fecundity was increased significantly in diet III, IV and V. The maximum (73.4%) fertilisation rate was observed in the diet-V group, followed by 61.3%, 56.8%, 49% and 22.7% in diet-I, diet-IV, diet-III and diet-II groups respectively. Most of the eggs in the diet-II treatment group remained immature. The various data thus obtained suggest that dietary supplementation of both n-3 and n-6 PUFA, is essential to improve gonadal maturation, breeding performance and spawn recovery in the Catla female broodstock.

Animal Feed↗

PubMed2000

Molecular markers and their use in animal breeding.

The use of DNA markers to define the genetic makeup (genotype) and predict the performance of an animal is a powerful aid to animal breeding. One strategy is known as marker-assisted selection (MAS). MAS facilitates the exploitation of existing genetic diversity in breeding populations and can be used to improve a whole range of desirable traits. DNA markers are, by definition, polymorphic, and the methods used to define DNA markers include restriction fragment length polymorphisms (RFLPs), microsatellites, and single nucleotide polymorphisms (SNPs). Linkage analysis, association analysis and analysis of gene function can be used to determine which polymorphisms are useful markers for desirable traits. Future prospects include the use of high throughput DNA microarray (DNA chip) technology which could revolutionize animal breeding in the next millennium.

Animal Husbandry↗

PubMed2004

7alpha-Hydroxypregnenolone acts as a neuronal activator to stimulate locomotor activity of breeding newts by means of the dopaminergic system.

It is becoming clear that steroids can be synthesized de novo by the brain and other nervous systems. Such steroids are called neurosteroids, and de novo neurosteroidogenesis from cholesterol is a conserved property of vertebrate brains. In this study, we show that the newt brain actively produces 7alpha-hydroxypregnenolone, a previously undescribed amphibian neurosteroid that stimulates locomotor activity. 7alpha-hydroxypregnenolone was identified as a most abundant amphibian neurosteroid in the newt brain by using biochemical techniques combined with HPLC, TLC, and GC-MS analyses. The production of 7alpha-hydroxypregnenolone in the diencephalon and rhombencephalon was higher than that in the telencephalon and peripheral steroidogenic glands. In addition, 7alpha-hydroxypregnenolone synthesis in the brain showed marked changes during the annual breeding cycle, with a maximal level in the spring breeding period when locomotor activity of the newt increases. Behavioral analysis of newts in the nonbreeding period demonstrated that administration of this previously undescribed amphibian neurosteroid acutely increased locomotor activity. In vitro analysis further revealed that 7alpha-hydroxypregnenolone treatment resulted in a dose-dependent increase in the release of dopamine from cultured brain tissue of nonbreeding newts. The effect of this neurosteroid on locomotion also was abolished by dopamine D(2)-like receptor antagonists. These results indicate that 7alpha-hydroxypregnenolone acts as a neuronal activator to stimulate locomotor activity of breeding newts through the dopaminergic system. This study demonstrates a physiological function of 7alpha-hydroxypregnenolone that has not been described previously in any vertebrate class. This study also provides findings on the regulatory mechanism of locomotor activity from a unique standpoint.

17-alpha-Hydroxypregnenolone↗