Reproducción

Título: Evaluation of corriedale and F1 with east friesian and texel on grazing conditions
Autores: Barbato, G.; Kremer, R.; Rista, L.; Sienra, I.; Rosés, L.; Neimaur, K. y Neirotti V.
Publicación: World Congress Animal Production, Porto Alegre, Brasil. October 26-31. CD. 2003.

Resumen

A study was made to evaluate the effect of maternal breed on: reproductive traits (fertility, fecundity and lambs survival ), wool production, lamb growth and carcass yield of lambs. The essay was made during 2 years, the ewes were Corriedale (C) (n= 75), F1 Texel x Corriedale (F1T) (n=98) and F1 East Friesian x Corriedale (F1EF) (n=91). The mating, with Hampshire Down rams, was in march/april, the lambing in august/september, shearing in october and the slaughter of all lambs at 32 kg. liveweight in december. The ewes and their lambs were running on implanted pastures (clover/festuca) all year around.

Fertility was higher in F1T than C or F1EF (P ? 0.01); fecundity was higher in F1EF than the others genotypes (P ? 0.01); lamb survival at 72 h was similar among breeds. Lamb marked/ewes mated was 92.6% in F1EF, 83.2% in F1T and 64.7% in C (P ? 0.01). Average daily gain of lambs from birth to 32 kg, was higher (P ? 0.01) in F1T (0.241 kg/d) and F1EF (0.241 kg/d) than in C (0.221 kg/d). Lamb carcass yield (%) was higher inF1T (46.2) and F1EF (45.7) than in C (43.3) (P ? 0.01). No differences among genotypes were found in GR, carcass measurements. In ewes, average greasy wool wight was 4.11±0.73 kg with no breed effect, but here was a breed effect (P ? 0.01) on wool yield and diameter.

Título: Inducción de lactancia mediante tratamiento hormonal en ovinos corriedale
Autores: Rosés, L.; Perdigón, F.; Sosa, L.; Barbato. G.; Rista, L. y Kremer, R.
Publicación: Primer Congreso Uruguayo de Producción Animal. Montevideo. 2-4 de octubre. 249-251. 1996.

Resumen

The objective of this study was to induce lactation through hormonal treatment in non-pregnat ewes. 14 adult Corriedale ewes (7 multiparous and 7 nulliparous) were inserted intravaginally with sponges containing medroxyprogesterone acetate and injected with estradiol-17? for 35 days. After withdrawal of the sponges, the ewes were given a dexametazone and oxitocin injection to initiate lactation. Individual milk production was recorded every 7 days. The results indicated that lactation was induced 100% of ewes treated by this method. Ewes were milked during 54 days reaching a milk yield of 12.67 litters per ewe in the period. No differences in milk production between nulliparous and multiparous ewes were noted, but differences in mammary growth were observed.

Título: Sincronización de celos en ovejas corriedale fuera de estación en un tambo ovino
Autores: Perdigón, F.; Sosa, L.;Barbato, G. y Bonzi, T.
Publicación: Primer Congreso Uruguayo de Producción Animal. 246-248. 1996.

Resumen

Since 1987 the milking of sheep has became a new enterprise mainly due the fall of the international wool prices. Corriedale were used as dairy ewes since their represent 70% of the whole uruguayan flock. Corriedales show oestrus from late January up to June and are mainly bred between February and March and milked from September to December. This assay was planned to demonstrate the presence of ovarian activity of its absence and to try to obtain oestrus during spring (October) in lactating sheep. 20 lactating and 20 open ewes were divided in to halves each, and one of each groups was treated with vaginal pessaries containing 40 mgr of PMA during 12 day. At the withdrawal of the pessaries 350 UI of PMSG were injected. The ewes were blood sampled from 7 days before the pessaries implant up to 7 days after their withdrawal to measure progesterone serum concentration by RIA. and vasectomized rams were used for heat detection. The efficacy of the treatment was about 72% and milk yield was not affected during it.

Título: Evaluation of corriedale and F1 with east friesian and texel on grazing conditions
Autores: Barbato, G.; Kremer, R.; Rista, L.; Sienra, I.; Rosés, L.; Neimaur, K. y Neirotti V.
Publicación: World Congress Animal Production, Porto Alegre, Brasil. October 26-31. CD. 2003.

Resumen

A study was made to evaluate the effect of maternal breed on: reproductive traits (fertility, fecundity and lambs survival ), wool production, lamb growth and carcass yield of lambs. The essay was made during 2 years, the ewes were Corriedale (C) (n= 75), F1 Texel x Corriedale (F1T) (n=98) and F1 East Friesian x Corriedale (F1EF) (n=91). The mating, with Hampshire Down rams, was in march/april, the lambing in august/september, shearing in october and the slaughter of all lambs at 32 kg. liveweight in december. The ewes and their lambs were running on implanted pastures (clover/festuca) all year around.

Fertility was higher in F1T than C or F1EF (P ? 0.01); fecundity was higher in F1EF than the others genotypes (P ? 0.01); lamb survival at 72 h was similar among breeds. Lamb marked/ewes mated was 92.6% in F1EF, 83.2% in F1T and 64.7% in C (P ? 0.01). Average daily gain of lambs from birth to 32 kg, was higher (P ? 0.01) in F1T (0.241 kg/d) and F1EF (0.241 kg/d) than in C (0.221 kg/d). Lamb carcass yield (%) was higher inF1T (46.2) and F1EF (45.7) than in C (43.3) (P ? 0.01). No differences among genotypes were found in GR, carcass measurements. In ewes, average greasy wool wight was 4.11±0.73 kg with no breed effect, but here was a breed effect (P ? 0.01) on wool yield and diameter.

Título: Inducción de lactancia mediante tratamiento hormonal en ovinos corriedale
Autores: Rosés, L.; Perdigón, F.; Sosa, L.; Barbato. G.; Rista, L. y Kremer, R.
Publicación: Primer Congreso Uruguayo de Producción Animal. Montevideo. 2-4 de octubre. 249-251. 1996.

Resumen

The objective of this study was to induce lactation through hormonal treatment in non-pregnat ewes. 14 adult Corriedale ewes (7 multiparous and 7 nulliparous) were inserted intravaginally with sponges containing medroxyprogesterone acetate and injected with estradiol-17? for 35 days. After withdrawal of the sponges, the ewes were given a dexametazone and oxitocin injection to initiate lactation. Individual milk production was recorded every 7 days. The results indicated that lactation was induced 100% of ewes treated by this method. Ewes were milked during 54 days reaching a milk yield of 12.67 litters per ewe in the period. No differences in milk production between nulliparous and multiparous ewes were noted, but differences in mammary growth were observed.

Título: Sincronización de celos en ovejas corriedale fuera de estación en un tambo ovino
Autores: Perdigón, F.; Sosa, L.;Barbato, G. y Bonzi, T.
Publicación: Primer Congreso Uruguayo de Producción Animal. 246-248. 1996.

Resumen

Since 1987 the milking of sheep has became a new enterprise mainly due the fall of the international wool prices. Corriedale were used as dairy ewes since their represent 70% of the whole uruguayan flock. Corriedales show oestrus from late January up to June and are mainly bred between February and March and milked from September to December. This assay was planned to demonstrate the presence of ovarian activity of its absence and to try to obtain oestrus during spring (October) in lactating sheep. 20 lactating and 20 open ewes were divided in to halves each, and one of each groups was treated with vaginal pessaries containing 40 mgr of PMA during 12 day. At the withdrawal of the pessaries 350 UI of PMSG were injected. The ewes were blood sampled from 7 days before the pessaries implant up to 7 days after their withdrawal to measure progesterone serum concentration by RIA. and vasectomized rams were used for heat detection. The efficacy of the treatment was about 72% and milk yield was not affected during it.