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Accueil du site → Doctorat → Brésil → Evaluation of the male effect on the reproductive performance of anglo-nubian goats raised in the semi-arid region of the State of Pernambuco

Universidade Federal Rural de Pernambuco (URFPE) 2011

Evaluation of the male effect on the reproductive performance of anglo-nubian goats raised in the semi-arid region of the State of Pernambuco

ALVES, Carlos Geraldo Tenório

Titre : Evaluation of the male effect on the reproductive performance of anglo-nubian goats raised in the semi-arid region of the State of Pernambuco

Avaliação do efeito macho sobre o desempenho reprodutivo de cabras da raça Anglo-Nubiana criadas no semi-árido do Estado de Pernambuco

Auteur : ALVES, Carlos Geraldo Tenório

Université de soutenance : Universidade Federal Rural de Pernambuco (URFPE)

Grade : Doutorado em Ciência Veterinária 2011

Résumé
The goal of this study was to evaluate the male effect on the reproductive performance of pluriparous goats of the Anglo-Nubian race, aged 24 to 60 months, raised in a semi-extensive regime in the semi-arid region of the State of Pernambuco. The goal of the first experiment was to gain further knowledge of the male effect, evaluating the influence of the distance separating males and females on the reproductive activity during a 45-day mating season of Anglo-Nubian goats (n=120), aged 24 to 60 months. The goats, raised in the semi-extensive regime in the semi-arid region of the State of Pernambuco, were kept 2 m (T1), 300 m (T2) and 2.000 m (T3) away from the male (n=3) 60 days before the start of the experiment, separated by shrubby vegetation fences during the dry season (DS) and the rainy season (WS). Before the experiments, a clinical- andrologic test was performed on the male while the females were selected based on the body condition score by vaginoscopic and ultra-sound testing ; they also received a dosage of progesterone in order to determine cyclicity. Both during the dry season (DS) and the rainy season (WS), the goats were equitably distributed into three groups. In T1, the goats were 2 m apart from the breeders, while in T2 they were 300 m apart and 2.000 m apart in T3. The first estrous in the DS occurred between the 2nd and the 22nd day of the breeding season and during the WS, it occurred between the 1st and the 23rd day. During the DS, the average value for the first manifestation of estrous was 7,13 ± 4,49 (T1), 8,84 ± 5,64 (T2) and 6,37 ± 4,21 (T3) days while in the WS it was 7,33 ± 5,74 (T1), 6,60 ± 4,88 (T2) and 8,10 ± 4,87 (T3) days, with no difference (P > 0,05) among treatments or among weather seasons. Estrous induction during the DS 100% (T1), 100% (T2) and 95,5% (T3) while in the WS it was 100% (T1), 100% (T2) and 100% (T3), with no difference (P > 0,05) among treatments in the DS and WS. Estrous synchronization during the DS occurred in 36,6% of the females, at 30% (T1), 35% (T2) and 45% (T3) while during the WS it occurred in 56,6 of the females, at 50% (T1), 60% (T2) and 60% (T3), with no statistical difference (P > 0,05) among treatments during the DS or WS. Percentage of pregnancy during the DS was 80% (T1), 70% (T2) and 75% (T3) while in the WS it was 90% (T1), 90% (T2) and 95% (T3), with no statistical difference (P > 0,05) among treatments in the DS and the WS. Prolificacy rate in the DS was 1,34 (T1), 1,33 (T2) and 1,35 (T3), and during the WS it was 1,35 (T1), 1,50 (T2) and 1,38 (T3), with no statistical difference (P > 0,05) among treatments in the DS or the WS. In the second experiment the goal was to also to further our knowledge of the male effect by evaluating the influence of the male/female ratio on the reproductive activity of the Anglo-Nubian goats (n = 180), aged 24 to 60 months. The goats were raised in a semi-extensive regime in the semi-arid region of the State of Pernambuco ; they were kept apart a distance of 300 m from the male (n = 3) 60 days before the start of the experiment, maintained fenced in by a shrubby type vegetation during the dry season (DS) and the rainy season (WS). Before the start of the experiment, the male were tested with a clinical andrologic examination while the females were selected by body condition score through vaginoscopic and ultrasound, besides measurement of concentration of progesterone to determine their cyclicity condition. Both in the dry season (DS) and the rainy season (WS), the goats were randomly and equitably distributed into three groups, whereas in T1:20, mating occurred in the male/female ratio of 1:20, in T1:30 mating occurred in the ratio of 1:30 and in T1:40, the ratio was 1:40. During the DS, the average value for first manifestation of estrous was 6,83 ± 4,57 (T1:20), 6,72 ± 4,56 (T1:30) and 7,05 ± 5,23 (T1:30) days, and during the WS, it was 6,60 ± 4,74 (T1:20), 6,70 ± 4,43 (T1:30) and 7,46 ± 4,54 (T1:40) days, with no statistical difference (P > 0,05) among treatments within the same weather period. Induction of estrous in the DS was 95,00% (T1:20), 80,00% (T1:30) and 75,50% (T1:40), and during the WS was 100% (T1:20), 100% (T1:30) and 97,5% (T1:40), with no statistic difference (P > 0,05) among treatments during the DS and the WS. Estrous synchronization during the DS occurred in 34,72% of the females, being 35,00% (T1:20), 36,66% (T1:30) and 32,50% (T 1:40) and during the WS it occurred in 65,75% of the females, being 65,00% (T1:20), 70,00% (T1:30) and 62,25% at (T1:40), with no statistical difference (P > 0,05) among treatments in the DS and WS. Percentage of pregnancy during the DS was 65,00% (T1:20), 70% (T1:30) and 62,50% (T1:30), while during the WS it was 90,00% (T1:20), 86,60% (T1:30) and 95% (T1:40), with no statistical difference (P > 0,05) among treatments during the DS and WS. Prolificacy rate during the DS was 1,30 (T1:20), 1,30 (T1:30) and 1,35 (T1:40), while in the WS it was PC 1,29 (T1:20), 1,25 (T1:30) and 1,30 (T1:40), with no statistical difference (P > 0,05) between treatments in the DS and WS. Results allow us to conclude that the male effect can be obtained by avoiding tactile contact between the breeder and the female, and that the 45-day breeding season can be performed both in the DS and in the WS, that the male effect can use obtained with any of the male/female ratio tested here and that any ratio can be used in the 45-day breeding season in the DS as well as the WS ; it will be necessary to observe grazing quantity and quality, especially during the DS, as well as body condition, body weight, post-partum period and the male/female ratio.

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