PREPUBERTAL PLASMA LH CONCENTRATION, OVULATION RATE AND PROLIFICACY IN FINN, SUFFOLK AND FINN-SUFFOLK EWES

1984 ◽  
Vol 64 (1) ◽  
pp. 67-72
Author(s):  
J. CHIQUETTE ◽  
F. MINVIELLE ◽  
J. J. DUFOUR

Fifty-seven Finn, Suffolk or Finn-Suffolk ewe lambs were used to study the relationships between prepubertal LH levels, measured at intervals between 2 and 10 wk of age, ovulation rate and litter size, both within and between genetic types. The most prolific group of ewes (Finn) did not have consistently higher mean levels of LH than the two other genetic groups possibly because the relationship between LH and number of ovulations among breeds may be age-dependent. On the other hand, within each genetic group, mean LH levels were generally higher in more prolific ewe lambs: small differences were observed up to 6 wk of age. These results show that early mean prepubertal LH concentration alone is not a precise indicator of future reproductive performance. Key words: Prepubertal plasma LH, ovulation rate, prolificacy, breed differences, ewes

1990 ◽  
Vol 70 (1) ◽  
pp. 55-65 ◽  
Author(s):  
F. CASTONGUAY ◽  
F. MINVIELLE ◽  
J. J. DUFOUR

Reproductive performance of Booroola × Finnish Landrace (BFL, n = 19) and Booroola × Suffolk (BS, n = 18) ewe lambs heterozygous for the F gene were compared to Finnish Landrace (FL, n = 14) and Suffolk (S, n = 26) purebred controls. FL lambs reached puberty earlier (211.3 d, P < 0.001) than the other genetic groups (237.8, 233.0 and 232.9 d for S, BS and BFL, respectively) whereas weight at puberty was lower (P < 0.001) for BFL, FL and BS (36.8, 36.7 and 47.0 kg, respectively) than for S (61.1 kg). About 95% of BFL and BS ewe lambs had at least one record of three ovulations or more over the first three estruses, including puberty. Mean ovulation rates at breeding (second estrus after puberty) to a Hampshire (H) ram were 3.8, 3.3, 2.2 and 1.7 for BFL, BS, FL and S, respectively (BFL and BS vs. FL and S, P < 0.001). The corresponding litter sizes at birth were 2.5, 2.1, 1.6 and 1.3 (BFL and BS vs. FL and S, P < 0.001) which reflected a higher embryonic loss in the Booroola crosses. Percentage ova loss ranged between 32.8% (BFL) and 12.8% (S) and was related to the level of prolificacy. Lamb mortality at birth was high in BFL (23.7%) compared to BS, FL and S (6.5, 0.0 and 0.0%, respectively, P < 0.001). Litter size at weaning (50 d of age) averaged 1.9, 1.8, 1.5 and 1.3 for BS, BFL, FL and S ewe lambs (BS vs. S, P < 0.02). Growth performance of H-sired progeny from the four genetic groups of ewes showed that H × S lambs had the highest average daily gain in both preweaning and postweaning periods (preweaning ADG: 349.9 g d−1; postweaning ADG: 332.1 g d−1) while the other genotypes of lambs performed equally (preweaning ADG: 267.4, 249.5 and 246.8 g d−1 for H × FL, H × BFL and H × BS, respectively; postweaning ADG: 281.2, 276.8 and 281.8 g d−1 for the same genetic groups). Overall productivity of ewe lambs in terms of kilograms of lamb produced showed a slight, nonsignificant, advantage for Booroola-cross ewe lambs (55.8 and 54.5 kg for BS and BFL) over purebred S (51.6 kg) and FL (44.9 kg). These results indicate that ovulation rate and litter size can be increased by incorporating F gene in both prolific (FL) and nonprolific (S) background genotypes without resulting in any significant difference in total weight of lamb produced per ewe. Key words: Sheep, ewe productivity, Booroola, ovulation rate, crossbreeding


1988 ◽  
Vol 68 (1) ◽  
pp. 69-81 ◽  
Author(s):  
MOHAMED H. FAHMY ◽  
JACQUES J. DUFOUR

Reproductive performance and body weight were studied on 361 ewes, representing Finnsheep (F), DLS (a population of 1/2 Dorset, 1/4 Leicester, 1/4 Suffolk) and seven combinations ranging from 1/8 to 7/8 Finnsheep breeding. Conception rate in yearlings was 61.5% for DLS compared to 89.0% for F with the crosses being intermediate. Conception rate in older ewes was similar in the different genetic groups (avg. 94%). Ovulation rate and litter size at birth of DLS ewes were 1.72 and 1.44 lambs, which was less than half those of F ewes (3.51 and 2.86 lambs, respectively). Both traits increased progressively with an increase in F breeding in crosses and with advances in age. DLS ewes weaned 1.22 lambs compared to 2.03 lambs for F ewes and 1.84 lambs for 4/8 F ewes. The heaviest litters at weaning (31.7 kg) were raised by 4/8 F ewes, followed by 7/8 F (30.8 kg) while those raised by DLS ewes weighed 23.0 kg and F ewes 29.1 kg. Percentage of ova lost per ewe mated averaged 24% and ranged between 18% (DLS and 1/8 F) and 29% (6/8 F). About 3.6% of lambs were born dead and a further 13.8% died before weaning. Preweaning mortality rate was highest in F (22.9%) and lowest in 3/8 F (9.4%). Average kilograms of lambs weaned per ewe exposed was highest in 4/8 F (27.6 kg) followed by F (26.0 kg), whereas that of DLS was the lowest at 18.1 kg. The 4/8 F cross showed 25% heterosis in kg of lambs weaned per ewe exposed and 52.5% increase over DLS. Significant positive linear regressions were calculated for ovulation rate, litter size and preweaning mortality rate on proportion of Finnsheep breeding in crosses. The relation was quadratic for percent ova lost and lamb mortality at weaning. Yearling DLS females weighted 36 kg compared to 44 kg for F yearlings. However, at 5 yr of age DLS ewes weighed 62 kg, 5 kg heavier than F ewes. The heaviest ewes at all ages were the 4/8 F (45 kg at 1 yr, 65 kg at 5 yr). Key words: Reproduction, DLS sheep, Finnsheep, crossbreeding, heterosis, repeatabilities


1993 ◽  
Vol 73 (2) ◽  
pp. 287-293
Author(s):  
S. L. Boyles ◽  
L. J. Johnson ◽  
W. D. Slanger ◽  
B. J. Kreft ◽  
J. D. Kirsch

Twenty-six of 52 heifers with an average liveweight of 318 kg were dewormed by intraruminal injection of oxfendazole and placed in drylot on 31 January. The other 26 animals served as controls. All heifers were pastured starting on 14 June and the treatment heifers were dewormed in the same manner as at the start of the experiment (31 January) on 1 July and 31 July. The groups started out with similar total worm eggs per gram of fecal sample, but the dewormed heifers had fewer counts each month thereafter. The drylot average daily gain of the treated heifers was higher (P = 0.01) and less variable (P = 0.12) and by 29 May these animals were heavier by 11.7 kg (P = 0.10). The treated animals did not gain as fast on pasture (P = 0.20), but the gain continued to be less variable (P = 0.09). Age at puberty was not different. Number of open heifers in the treated group was 4 vs. 15% for the control group (P = 0.18). Deworming by intraruminal injection resulted in faster feedlot gains, more uniform gains during both drylot and pasture, reduced parasites and no abscess at injection sites. Key words: Anthelmintics, oxfendazole, cattle, heifers


2014 ◽  
Vol 54 (6) ◽  
pp. 762 ◽  
Author(s):  
B. L. Paganoni ◽  
M. B. Ferguson ◽  
S. Fierro ◽  
C. Jones ◽  
G. A. Kearney ◽  
...  

The reproductive performance of Merino ewe lambs is lower than that achieved by mature ewes and is highly variable. It is likely that embryo loss represents a major source of reproductive wastage in Merino ewe lambs, but to our knowledge no studies have attempted to determine when the major reproductive losses occur or identify predisposing factors that are likely to lead to high rates of pregnancy failures in ewe lambs. After characterising where reproductive losses occurred in Merino ewe lambs mated at 8–10 months of age, we tested the hypothesis that pregnancy failure in ewe lambs is influenced by nutrition and liveweight change around conception and the genetic potential for growth of the ewe lamb. Two-hundred and twenty-four Merino ewe lambs born from 10 sires with Australian Sheep Breeding Values were teased for 14 days using vasectomised rams, and then fed two different diets for 68 days during mating. All ewe lambs were weighed and the appearance of crayon marks on their rump was recorded most days. Blood samples for progesterone assay were collected on Days 5, 12 and 17 after the first record of a crayon mark. Ultrasonography using a trans-rectal probe was used to measure the number of corpora lutea present, as a proxy for ovulation rate, 9 days after the first record of a crayon mark during the mating period. A further trans-rectal ultrasonography was undertaken 30 days after marking from the entire ram to determine pregnancy status and count the number of embryos. Over the entire mating period 54% of ewe lambs were pregnant with 66 fetuses per 100 ewes mated. The average ovulation rate was 150% however up to 84% of this potential was lost by weaning and the major contributor to this apparent deficit was the loss that occurred during the first 17 days after mating. Pregnancy failure was not significantly related to nutrition or liveweight change during mating however, there were significant differences in pregnancy failure between different sire groups. Pregnancy failure was significantly less for ewe lambs from sires with higher breeding values for weight and fat at post-weaning age (8–10 months). Only 60% of ewe lambs had achieved puberty when rams were introduced and only 83% by 35 days after mating. In addition, almost half of the ewe lambs that were mated for the first time during the first 35 days after rams were introduced, but failed to get pregnant, then seemed to skip a cycle or did not cycle again before the end of the 68-day mating period. Liveweight at introduction of entire rams was positively related to fertility, ovulation rate and reproductive rate. This study confirms that selection of sires with higher breeding values for post-weaning weight and fat will increase the fertility and reproductive rate of Merino ewe lambs mated at 8–10 months. This response is due in part to enhancing the onset of puberty and increasing the proportion of ewe lambs cycling at the start of mating and reducing pregnancy failure.


1989 ◽  
Vol 69 (2) ◽  
pp. 307-314 ◽  
Author(s):  
M. H. FAHMY

Ovulation and lambing records of 214 ewes from nine genetic groups varying in ovulation rate (OR) from 1.8 to 3.2 corpora lutea (CL) and number of lambs born (LB) from 1.2 to 2.1 were analyzed to study the relation between OR, LB, ova loss (OL) and their repeatabilities. The nine genetic groups were DLS, Finnsheep (F) and seven crosses from these two breeds ranging from 1/8 to 7/8 Finnsheep breeding. Intrayear repeatability of OR averaged 0.59 for all genetic groups combined. It ranged from −0.20 for DLS to 0.93 for 5/8 F. Interyear repeatability averaged 0.38 and ranged from 0 for DLS to 0.54 for 3/8 F. OR showed a linear increase (b = 0.22 ± 0.02) with increase in Finnsheep breeding whereas repeatabilities showed a significant quadratic relationship. Repeatability of OR was more associated with variability than with mean OR. Repeatability of OR for ewes which had 1, 2, 3 or 4 CL at first record and averaged 2.3 ± 0.5,2.5 ± 0.7,3.4 ± 1.0 and 3.4 ± 1.3 CL at the following two records was, −0.09, 0.33, 0.42 and 0.42, respectively. Lambs born increased with the increase in Finnsheep breeding from 1.2 for DLS to 2.1 for Finnsheep. Ova loss averaged 35% and was fairly constant in the different genetic groups. Repeatabilities for LB and OL for each genetic group were generally small and mostly nonsignificantly different from zero. For the genetic groups combined the estimates were 0.15 and 0.14 for LB and OL, respectively. The correlation between OR and LB (0.25) was lower than that between OR and OL (0.58) and LB and EM (−0.62). Key words: Ovulation rate, litter size, ova loss, repeatability, Finnsheep crosses, DLS sheep


Author(s):  
María Luisa Pfeiffer

ResumenLa ética, como praxis debe crear espacios de convivencia que permitan descubrir cuál es la característica de los espacios de dominación en que habitamos y tratar de construir otros donde los hombres y los pueblos puedan vivir libremente su destino. El planteo de este trabajo es que, en  América Latina, el espacio biotecnológico debido a que es una gran fuente de ambigüedades cuando de valores se trata, termina siendo aliado de los poderes dominantes. Se analiza especialmente esa característica en el uso de la ingeniería genética para la transformación de semillas, mostrando que si bien por un lado se puede considerar a la misma como una resultante valiosa de la ciencia, por el otro resulta dañina no sólo en lo relativo a la conservación de la vida con toda su diversidad, sino en lo económico, social, cultural, antropológico e incluso médico. El propósito final del trabajo es una reflexión sobre el mito del progreso asociado al crecimiento de la biotecnología y la necesidad de establecer límites éticos al mismo.  Palabras clave: Biotecnología, tecnociencia, progreso, transgénicos, América Latina.***************************************************The relationship between biotechnology and progress as “unquestioned values”, its ethical and political implicaturesAbstractEthics, as praxis, must create spaces for coexistence that allow us to discover what is the characteristic of the domination spaces we live in, as well as to create others where individuals and peoples can live their destiny in a free way. This paper states that in Latin America, given that it is a source of  ambivalence when thinking about values, biotechnology ends up being an ally of the dominant powers. This characteristic is specially analyzed in the use of genetic engineering for seed transformation, showing that, even though it can be considered as a valuable result of science, on the other hand it is hazardous not only in regards to conservancy of life in all its diversity, but also in economic, social, cultural, anthropological, and even, medical respects. The final aim of the paper is to stimulate a reflection about the myth of progress associated to the growth of biotechnology, and to state theneed to establish ethical limits to it. Key words: biotechnology, techno-science, progress, transgenic, Lain America***************************************************A relação entre biotecnologia e progresso como “valores indiscutidos”, suas implicações éticas e políticasResumoA ética, como práxis, deve criar espaços de convivência que permitam descobrir qual é a característica dos espaços de dominação em que habitamos e tratar de construir outros onde os homens e os povos possam viver livremente seu destino. O foco deste trabalho é que na América Latina o espaço biotecnológico devido a que é uma grande fonte de ambiguidades quando de valores se trata, acaba sendo aliado dos poderes dominantes. Analisa-se especialmente essa característica no uso da engenharia genética para a transformação de sementes, mostrando que se bem por um lado se pode considerar a mesmo como uma resultante valiosa da ciência, pelo outro resulta danosa nãosó no relativo à conservação da vida com toda sua diversidade, mas no econômico, social, cultural, antropológico e até no médico. O propósito final do trabalho é uma reflexão sobre o mito do progresso associado ao crescimento da biotecnologia e à necessidade de estabelecer limites éticos ao mesmo. Palavras chave: Biotecnologia, tecnociência, progresso, transgênicos, América Latina.


1993 ◽  
Vol 57 (2) ◽  
pp. 281-286 ◽  
Author(s):  
M. C. G. Davies ◽  
N. F. G. Beck

AbstractAn investigation was conducted to compare, the LH, prolactin and progesterone profiles of ewe lambs with ewes during oestrus and early pregnancy. Peak LH concentration was significantly lower (P < 0·05) and duration of release tended to be shorter during oestrus in ewe lambs. Furthermore, this smaller LH peak tended to be associated with a lower ovulation rate. LH pulse rate, amplitude and concentration were similar in both groups during day 13 of pregnancy. However, LH concentration was higher in ewe lambs compared with ewes on day 28 of pregnancy. Peak prolactin concentration was lower during oestrus in ewe lambs (P < 0·05) but there was no difference between the two groups during early pregnancy. Plasma progesterone concentrations were similar in both groups until day 13 of pregnancy. Thereafter, mean progesterone concentration was lower, from day 14 to 30, in the ewe lambs (P < 0·05). These results indicate that in ewe lambs and ewes maintained under identical conditions plasma hormone profiles differ during oestrus and early pregnancy. Moreover, these differences probably contribute towards the lower reproductive performance of ewe lambs.


1982 ◽  
Vol 62 (4) ◽  
pp. 1063-1078 ◽  
Author(s):  
A. J. LEE ◽  
A. J. McALLISTER ◽  
T. R. BATRA ◽  
A. E. EMSLEY ◽  
J. P. F. DARISSE ◽  
...  

Body weights and measurements were compared among several genetic groups from the 496 Holstein-based H line heifers and 344 Ayrshire-based A line heifers. Differences among herds (Charlottetown, P.E.I., Lennoxville and Normandin, Que.; Ottawa, Ont., and Lethbridge, Alta) were large and highly significant (P < 0.01) for age at first calving and all weights and measurements except birth weight. Year and season of birth effects were small and generally not significant (P > 0.05). Birth weights were 4.1 kg lighter for calves from first parity dams and 1.4 kg lighter for second parity dams than fourth or later parity dams. Heifers calving at earlier ages for the first time were generally heavier and larger at 66 and 82 wk than those calving later, reflecting the effects of concurrent pregnancy. H line heifers were significantly heavier and larger in all measurements than A line heifers. Differences among the Canadian, American, and Research Branch Holstein sire groups were small and generally not significant (P > 0.05). Brown Swiss progeny were significantly (P < 0.05) taller at the withers and longer in the rump and generally larger than progeny of other A line sire groups. Norwegian Red progeny were the most similar to the Brown Swiss, followed by the other Ayrshire groups. Key words: Growth, heifers, Holsteins, Ayrshires, Brown Swiss, Norwegian Red


2020 ◽  
pp. 43-61
Author(s):  
Karolline Pacheco

This article aims to reflect on the challenges and potential of heritage education in the context of the Federal District from a sociomuseological perspective. Considering that memory is the foundation for the construction of social identity and that this process is permanently redefined in the dialogical relationship with the other, heritage and museums are important instruments to reestablish these dialogues of diversity. In the face of museums and cultural spaces that reiterate the consecrated discourse about the construction of Brasilia, privileging specific names and facts, how to effectively enforce the relationship between heritage, identity and citizenship? I seek through experience as an educator in a cultural space to reflect on perceptions, potentialities and approaches that aim to overcome the unique history including other voices in this relationship in view of an education for autonomy and cultural democratization. Key Words: Heritage. Heritage Education. Cultural Diversity. Brasília. Federal District.


1996 ◽  
Vol 62 (1) ◽  
pp. 79-83 ◽  
Author(s):  
N. F. G. Beck ◽  
M. C. G. Davies ◽  
B. Davies

AbstractAn investigation was conducted to compare late embryonic losses in ewe lambs and ewes and to determine the effect of inducing embryonic mortality on day 15 of pregnancy on reproductive function in ewe lambs. Ovulation rate and embryo survival were determined, at 15 and 30 days after mating, in a total of 83 ewe lambs and 67 ewes. Ovulation rate was lower, at spontaneous oestrus, in ewe lambs (1·07) than in ewes (1·25; P < 0·05). There was no difference in embryo survival at day 15, as 79% of ewe lambs and 80% of ewes contained expanded conceptuses. However, embryo survival was lower in ewe lambs (69%) than ewes (88%) at day 30 (P < 0·05). Embryonic mortality was induced in an additional 18 ewe lambs with an intrauterine injection of colchicine on day 15 post mating. Four of these animals had normal length oestrous cycles, six had inter-oestrus intervals ranging from 22 to 35 days and eight did not return to oestrus. Overall, the results of this study demonstrate that low ovulation rate and late embryonic losses make a significant contribution to subfertility in ewe lambs. Moreover, conceptus death is associated with luteal persistence, which may reduce reproductive performance by preventing remating.


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