World Rabbit Science - Vol. 23 (2)-2015https://riunet.upv.es:443/handle/10251/525472024-03-28T22:44:48Z2024-03-28T22:44:48ZMilk yield prediction at late lactation in reproductive rabbit doesArnau Bonachera, AlbertoCervera Fras, Mª ConcepciónBlas Ferrer, EnriquePascual Amorós, Juan Joséhttps://riunet.upv.es:443/handle/10251/526662023-11-21T11:52:14Z2015-07-03T09:48:37ZMilk yield prediction at late lactation in reproductive rabbit does
Arnau Bonachera, Alberto; Cervera Fras, Mª Concepción; Blas Ferrer, Enrique; Pascual Amorós, Juan José
[EN] Separating kits and mother to determine milk yield at 4th wk of lactation (MY4) could have negative consequences on the training and development of young rabbits. In this work, a total of 313 lactation curves (28 d long), taken from 2 different trials, were used to fit regression models to estimate MY4. In both trials, females were subjected to a semi-intensive reproductive rhythm [insemination at 11 d post-partum (dpp) and weaning at 28 dpp], but diets, genetic types, parity order and day of controls were slightly different. The models included variables which, according to the bibliography, are related to milk yield and are often recorded in joint management (without separation of litters rom mothers), such as litter size at weaning (LSW; both linear and quadratic), joint energy intake of doe plus litter at 4th wk of lactation (JEI; both linear and quadratic), perirenal fat thickness change (ΔPFTd) and milk yield at 3rd wk (MY3). The overlapping degree (OL) between current lactation and next pregnancy was included as a dummy variable, as well as their interactions with quantitative traits. To fit these models, 3 procedures were proposed to obtain accurate equations with biological meaning: Eq1, multiple linear regression (MLR) of data; Eq2, MLR with previous smoothing of sample distribution; and Eq3, MLR with previous smoothing and avoiding redundant samples and collinearities among variables. MY3 had a positive and relevant linear effect on MY4 for the 3 equations obtained (responsible for 39 to 50% of MY4 prediction). JEI had also a relevant role in MY4 prediction (28 to 61%), its positive effect being linear on Eq1, quadratic on Eq2 and both linear and quadratic on Eq3. ΔPFTd and LSW related traits were only included in Eq3, with a low relative weight, and OL inclusion did not improve prediction in any equation. Predicting MY4 was possible with the variables used, although certain precautions must be taken. Traditional MLR seems to predict central values properly, but extreme values poorly, whereas pre-treatment of data to smooth the dependent variable distribution appears to improve prediction of extreme values.
2015-07-03T09:48:37ZChanges in responsiveness to kit odours across pregnancy: relevance for the onset of maternal behaviourChirino, RosarioGonzález-Mariscal, Gabrielahttps://riunet.upv.es:443/handle/10251/526652023-11-21T11:52:14Z2015-07-03T09:29:02ZChanges in responsiveness to kit odours across pregnancy: relevance for the onset of maternal behaviour
Chirino, Rosario; González-Mariscal, Gabriela
[EN] Virgin does are indifferent to foster kits but lesions to the main or accessory olfactory systems allow them to behave “maternally” (i.e., they crouch over the litter and allow suckling). This suggests that kit-derived olfactory cues are aversive to virgins but not to lactating does. We hypothesised that the valence of such olfactory cues changes throughout gestation so that, at parturition, does are attracted to the newborn and can then show placentophagia, clean the kits and nurse them. To explore this hypothesis we exposed does to 2 nest boxes containing a variety of pup-derived vs. “neutral” odours, quantifying the number of sniffs and entrances to each box over 60 min. Virgins, confronted with 2 different types of contrasts, showed no significant differences in the number of sniffs or entrances directed at any of the 2 boxes. Pregnant rabbits sniffed the “kit-odour” box significantly more than the “neutral” one as early as gestation day 7, depending on the animals’ experience with the experimental setup and kit odours as virgins. The number of sniffs declined in late pregnancy in all groups. Entrances into the “kit-odour” box were few and significantly higher than those shown towards the “neutral” box only in 1 group. Our findings agree with a correlation between a shift in the valence of kit-derived olfactory cues and the hormonal changes known to occur throughout pregnancy. The relevance of this phenomenon for the onset of maternal responsiveness at parturition is discussed.
2015-07-03T09:29:02ZSemen characteristics and sexual hormones of Hy-Plus rabbit bucks influenced by a dietary multi-enzymes additiveGado, H.Mellado, M.Salem, A.Zaragoza, A.Seleem, T.S.T.https://riunet.upv.es:443/handle/10251/526632023-11-21T11:52:14Z2015-07-03T09:25:33ZSemen characteristics and sexual hormones of Hy-Plus rabbit bucks influenced by a dietary multi-enzymes additive
Gado, H.; Mellado, M.; Salem, A.; Zaragoza, A.; Seleem, T.S.T.
[EN] A total of 144 adult Hy-Plus rabbit bucks were randomly assigned into four treatments of 36 replicates each, in a completely randomized design. Animals were fed ad libitum on basal diet supplemented with an enzyme complex (EZ) at 0 (EZ0), 1 (EZ1), 3 (EZ3) and 5 (EZ5) kg/ton of feed. Total sperm count was higher (P<0.05) in EZ5 than in EZ0. Sperm motility increased with increasing levels of the EZ additive being lowest for EZ0 and highest for EZ5 rabbits (P<0.05). Percentage of dead sperm was higher (P<0.05) in EZ0 than in EZ5 rabbits. Rabbit bucks received the highest levele of EZ in their diet, had the shorter reaction time (22.31±3.17 sec; P<0.05),whereas EZ5 bucks took 43.56±5.89 sec to mount does for the first time after exposure. Blood testosterone, 17α-estradiol and progesterone levels were highest in EZ5 rabbits and lowest in EZ0 rabbits. Enzyme addition increased (P<0.05) sperm transit in estrus doe cervical mucus. Data suggested that the EZ additive in diets of adult Hy-Plus rabbit bucks was effective to improve both semen characteristics and sexual drive.
2015-07-03T09:25:33ZEffect of human menopausal gonadotropin on testicular morphometry, gonadal and extragonadal sperm reserves of rabbit bucksAnsa, Anietie ArchibongImasuen, James A.https://riunet.upv.es:443/handle/10251/526622023-11-21T11:52:14Z2015-07-03T09:22:27ZEffect of human menopausal gonadotropin on testicular morphometry, gonadal and extragonadal sperm reserves of rabbit bucks
Ansa, Anietie Archibong; Imasuen, James A.
[EN] Testicular morphometry, gonadal and extragonadal sperm reserves of rabbit bucks treated with Human Menopausal Gonadotrophin (Menogon®) were studied. Twenty-four crossbred rabbit bucks weighing 1.3-1.6 kg at 15-17 wk were randomised into 4 treatment doses of 0 (control), 7.5, 15.0, and 22.5 I.U. in a completely randomised design with 6 bucks per group. A vial of Menogon® was reconstituted in 1 mL of physiological saline solution and administered intramuscularly at 72 h intervals for 56 d prior to commencement of sample collection. Parameters evaluated were ejaculate concentration, testicular morphometry, gonadal and extragonadal sperm concentrations. Results for ejaculate concentration (86, 110, 186, and 135×106/mm3) revealed a significantly (P<0.05) higher difference in the 15.0 I.U. group. Gonadal and extragonadal sperm reserve indices were not significantly (P>0.05) affected by the treatment. Testicular morphometry results showed that paired testis volume (cm3), testis circumference (cm), ductus deferens length (cm) and epididymal length (cm) were significantly (P<0.05) different, with a progressive increase that corresponds to increased Menogon® administration. High and positive correlations (P<0.01) were observed between testis weight and gonadal sperm reserves (r=0.99) and body weight and gonadal sperm reserves (r=0.99). Similarly, correlations between epididymal weight and epididymal sperm reserves (r=0.85), testis weight and ejaculate concentration (r=0.97), body weight and ejaculate concentration (r=0.96), body weight and testis weight (r=0.97), testis volume and ejaculate concentration (r=0.97), testis volume and gonadal sperm reserve (r=0.91), testis volume and testis weight (r=0.96), and testis volume and body weight (r=0.90) were positive and significant (P<0.05). Taking all the reported results into consideration, controlling the amount of Menogon® administration at 15.0 I.U. for rabbit bucks could be a promising approach to regulating testosterone synthesis and secretion, thereby affording a potential method of enhancing fertility.
2015-07-03T09:22:27ZAbstracts of the 40th Symposium on Cuniculture, ASESCU Santiago de Compostela, Spain, 28th-29th May, 2015https://riunet.upv.es:443/handle/10251/526612023-11-21T11:52:14Z2015-07-03T09:18:38ZAbstracts of the 40th Symposium on Cuniculture, ASESCU Santiago de Compostela, Spain, 28th-29th May, 2015
[EN] The 40th Congress of the Spanish Association of Cuniculture (ASESCU) was held in Santiago de Compostela from 28th to 29th May 2015. This is the 40th edition of the conference, held annually without interruption since 1976. Main papers focused on analysing the current rabbit sector situation in the north-western Iberian Peninsula, genetic improvement of meat rabbit and foundation of new lines. The future of meat rabbit production and the rabbit meat production value chain was discussed, with the results of the partnership between the Spanish Institute of Agricultural Research (INIA) and the rabbit marketing board (INTERCUN) to support research projects. A round table was also held on coccidiosis in rabbit farms. In addition, a total of 32 communications were presented both in working sessions with oral communications and posters (pathology, nutrition, reproduction, ethology, production and products). The meeting was attended by more than 200 participants, including researchers from Spain, Portugal, Mexico, Ecuador and Egypt, among other countries. Abstracts of the contributions presented are reported below.
2015-07-03T09:18:38Z