Interaction of reproduction rhythm, suckling and parity on mating incidence, ovarian dynamics and estrogen secretion in the rabbit doe

The effects of suckling and remating interval (11 or 21 d post partum) were studied in primiparous (P=25) and multiparous (M=23) hybrid rabbits. In P rabbits, suckling had no significant effect on mating incidence; however, a higher percentage of females accepted the male on d 11 than on d 21 (P<0.01). In M rabbits, no significant differences in mating performance due to either day, suckling or their interaction were found. A higher proportion of nonsuckled than suckled P rabbits ovulated (P<0.01). Ovulation incidence was not affected significantly by day of mating, suckling or their interaction in M rabbits. A comparison of the day influence in P and M rabbits on mating incidence showed a greater effect in the P (P<0.05) while the suckling effect on ovulation performance showed an insignificant difference in the two parity groups. Ovulation rate, as assessed by ultrasound, was not influenced significantly by day or suckling in either P or M rabbits. The follicle distribution was marked by fewer large follicles and lower plasma estrogen levels were detected in suckled than in nonsuckled P and M rabbits (P<0.05). Further research is needed to elucidate these phenomena also when AI is performed

Influence of weaning age (28 vs. 63 d) on quantitative and qualitative carcass traits of rabbits

Nowadays there is an increasing interest towards breeding systems, also for rabbit meat production, that are more mindful of animal welfare through an attenuation of the productive cycles intensity. These particular rearing techniques provide a delaying of the weaning age to reduce young rabbits stress. The present experiment is part of a wider research (Pinna et al., 2004; Marongiu et al., 2004) conducted in a sardinian farm in which rabbits are usually weaned at about 60 days of age. Surely this managerial choice could be considered rather questionable but from a scientific point of view could also represent the occasion to examine the productive performance of rabbits submitted to such a late weaning. The final part of the survey, regarding the carcass composition and the meat chemical-nutritional characteristics, was carried out through the comparison of two groups of rabbits weaned at 28 and at 63 days of age respectively

A Procedure for rabbit blood serial collection

Blood serial collection is required for many applied reproduction and nutrition trials with rabbits. The experimental design of these researches very often includes repeated samplings of large volumes of blood for metabolites and hormones analysis. Our proposed procedure has been tested in many surveys with success. It is based on a blood collection by aspiration, featuring a sterile butterfly cannula with a vacuum tube. By this procedure, the use of syringes is avoided. As a matter of fact when a syringe is used, excessive suction frequently causes the rabbit blood vessel collapse. Furthermore a rough handling of blood, such as excessive suction or the forcing of clotted blood from a syringe, will cause hemolysis: this can interfere with the serum or plasma fractions needed. Blood collection from ear vessels is a technique commonly used with rabbits. The central ear artery is recommended for collecting larger volumes of blood (over 5ml). 10ml of blood/kg body weight can be collected in this manner but the rabbit must be carefully restrained and hematomas must be prevented by direct pressure. Removal of more than 10% of blood volume may result in hypovolemic shock, a potentially fatal reaction. Materials. For local anesthesia EMLA Cream (Lidocaine 2.5% + Prilocaine 2.5%) is a topically applied local anesthetic that is very useful in removing sensation from the venipuncture site. Blood collection set: 1) Butterfly cannula (23 gauge needle for small blood samples and 21 gauge for large samples). 2) Vacutainer blood collection tube and vacutainer holder. 3) Luer adapter (which is designed to allow the attachment of the butterfly to holders using a single venipuncture). Procedure. a) Remove the rabbit from its cage. Proper technique in grabbing and carrying a rabbit is important to prevent vertebral fractures. Grab the rabbit's skin in the shoulder region and place its head underneath your arm. Support the rabbit's legs with the hand of the arm that the head is tucked under. Alternatively, grab the rabbit's skin with both hands (over both the shoulder and the rump region). b) Apply about one thumb size of anesthetic cream on the site selected for blood collection, and leave the cream in contact with skin for 5 minutes c) Check the ear artery if visible and if doesn't dilate, tapping it gently (or flicking it) may help. For vessels dilation the use of topical irritants such as xylene is not recommended. Xylene tends to cause leukocytosis and if it comes in contact with blood, will cause hemolysis. Adequate dilation of vessels can generally be achieved by use of a heat lamp, alcohol or gentle massaging of the ear. d) Only when the blood vessel is clearly visible, with the needle bevel up, parallel to, and alongside the artery, insert the needle quickly under the skin and then into the artery. The needle has to be pointed towards the base of the ear and the insertion into the skin and artery can be performed in one complete motion. e) If the blood vessel has been correctly entered, blood will flow into the tubing of the butterfly cannula. f) Push the vacutainer tube all the way into the holder; vacuum is broken, and blood flows freely being drawn from the artery into the tube. g) Once the blood sample has been taken, the needle must be carefully and quickly removed. When the desired amount is collected, gently hold gauze over needle entry point and remove the needle. h) Hemostasis should be achieved applying pressure to the injected area using thumb and a piece of cotton. Keep pressure on the area for 60-90 seconds, or until blood stops flowing. i) Observe the rabbit for at least another 30 seconds to insure that bleeding has stopped. l) Return rabbit to cage, and check again in 10-15 minutes

A Six-year investigation on reproductive performance of hybrid rabbits: 1.: pregnancy rate and numerical productivity at weaning as affected by season

With the aim to clarify the effect of seasonal variation on reproductive performance of hybrid rabbits, a six-years investigation was carried out. Traits analysed were pregnancy rate of does and numerical productivity at weaning. The data set included: 33588 matings and subsequent pregnancy diagnosis; 245743 young rabbits at weaning. From the statistical analysis, pregnancy rate and numerical productivity at weaning appeared to be significantly (P<0.001) affected by seasonal variation. Furthermore a statistically significant (P<0.001) month influence was also found. Nevertheless a correlation between the two parameters needs to be performed to supplement our analysis

Effect of pre-weaning solid feed and milk intake on caecal content characteristics and performance of rabbits around weaning

The aim of this study is to know the effect of different solid feed and milk intake during suckling on performance around weaning and on caecal content characteristics at weaning. In order to obtain different intakes of milk and solid feed, 13 litters of pregnant females (PF) inseminated the day after delivery and 14 litters of non-pregnant females (NPF) were compared. At birth the litters were equalized at eight pups and during lactation dead pups were replaced by pups of the same age from nursing does. Compared to the PF group, rabbits in the NPF group had a higher milk intake (26.0 versus 21.4 g/day; P < 0.01) and lower solid feed intake (9.1 versus 11.5 g/day; P < 0.01) between 20 and 28 days of age. No significant difference was observed between the two groups in weight gain before and post-weaning (28-49 days). At weaning, the rabbits in group PF showed higher values in caecal content (g 26.3 versus 22.6; P < 0.05) and volatile fatty acids (mmol/l 52.2 versus 43.6; P < 0.01) and lower values in empty caecal weight (g 7.18 versus 7.78; P < 0.05), C3 (6.4 versus 9.3%; P < 0.01) and C3/C4 ratio (0.39 versus 0.63; P < 0.01) than the group NPF. On the basis of the above results, it may be concluded that the quantity of solid feed and milk intake before weaning influenced the charac- teristics of the caecal content, but not the performance of rabbits around weaning

Evaluation of the response to buserelin administered 24 hours prior to artificial insemination in Sarda ewe: follicular dynamics after ovulation

Failure of fertilization and embryo loss during early gestation are major determinants of reproductive efficiency in Sarda ewe. A number of studies have demonstrated that treatment with the GnRH analogue buserelin on day 12 post insemination reduces embryo mortality in cattle and sheep. In response to this treatment, large ovarian follicles (LF) and circulating oestrogens are supposed to decrease; the resulting elevation in progesterone secretion, due to the increased number of active corpora lutea (CL), should facilitate embryo implantation. The aim of this research was to investigate the ovarian effect of buserelin adminstered 24 h prior to A.I. in Sarda ewe

Characterization of milk composition, coagulation properties, and cheese-making ability of goats reared in extensive farms

The aims of this study were to explore the variability of milk composition, coagulation properties, and cheese-making traits of the Sarda goat breed, and to investigate the effects of animal and farm factors, and the geographic area (Central-East vs. South-West) of an insular region of Italy, Sardinia. A total of 570 Sarda goats reared in 21 farms were milk-sampled during morning milking. Individual milk samples were analyzed for composition, traditional milk coagulation properties (MCP), modeled curd-firming over time parameters (CFt), and cheese-making traits (cheese yield, %CY; recovery of nutrients, %REC; daily cheese yield, dCY). Farms were classified into 2 categories based on milk energy level (MEL; high or low), defined according to the average net energy of milk daily produced by the lactating goats. Milk yield and composition were analyzed using a mixed model including the fixed effects of MEL, geographic area, days in milk, and parity, and the random effect of farm within MEL and geographic area. Data about MCP, CFt, and the cheese-making process were analyzed using the same model, with the inclusion of the effects of animal and pendulum of the lactodynamograph instrument, allowing the measure of repeatability of these traits. Results showed that animal had greater influence on coagulation and cheese-making traits compared with farm effect. Days in milk influenced milk composition, whose changes partly reflected the modifications of %CY traits. Moreover, large differences were observed between primiparous and multiparous goats: primiparous goats produced less milk of better quality (higher fat, lower somatic cell and bacterial counts) and less cheese, but with higher recovery of fat and protein in the curd, compared with multiparous goats. The repeatability was very high, for both coagulation (84.0 to 98.8%) and cheese-making traits (89.7 to 99.9%). The effect of MEL was significant for daily productions of milk and cheese, coagulation time, and recovery of protein in the curd, which were better in high-MEL farms. As regards geographic area, milk composition and percentage cheese yield were superior in the Central-East area, whereas daily milk and cheese production and MCP were better in the South-West. This result was explainable by the phenomenon of crossbreeding Sarda goats with Maltese bucks, which occurred with greater intensity in the South-West than in the Central-East area of the island. The results provided by this study could be of great interest for the goat dairy sector. Indeed, the methods described in the present study could be applicable for other farming methods, goat breeds, and geographic areas. The collection of a wide range of phenotypes at individual animal level is fundamental for the characterization of local populations and can be used to guarantee breed conservation and the persistence of traditional farming systems, and to increase farmers' profit

On the presence of the Endangered white skate Rostroraja alba in Sardinian waters

The white skate Rostroraja alba is assessed by the International Union for Conservation of Nature as Endangered globally and is now considered rare in the Mediterranean. This species has never been recorded in Sardinian seas (central western Mediterranean), but an empty eggcase was collected on a sandy bottom off the western Sardinia coasts during the MEDiterranean International Trawl Survey (MEDITS) program in 2019. A morphometric and morphological description of the Sardinian eggcase, after a comparison with measurements from other Mediterranean and Atlantic specimens, showed it to be clearly ascribable to Rostroraja alba

Bacterial and viral investigations combined with determination of phytoplankton and algal biotoxins in mussels and water from a Mediterranean coastal lagoon (Sardinia, Italy).

Calich Lagoon is a Mediterranean coastal lagoon located along the northwestern coast of Sardinia (Italy). The connection to marine and fresh water determines the high productivity of this coastal lagoon. Despite its great potential and the presence of natural beds of bivalve mollusks (Mytilus galloprovincialis), the lagoon has not yet been classified for shellfish production. In this study, through a multidisciplinary approach, the presence of several bacterial pathogens (Escherichia coli, Salmonella spp., and Vibrio spp.) and viral pathogens (hepatitis A virus and norovirus genogroups I and II) was evaluated from March 2017 to February 2018. In addition, phytoplankton composition in lagoon waters and associated algal biotoxins (paralytic and diarrhetic shellfish poisoning) in mussels were also monitored. The aim of this study was to provide useful data to improve knowledge about their seasonal presence and to assess the potential risk for public health, as well as to provide input for future conservation and management strategies. In mussels, Salmonella spp. were found in spring, along with E. coli, but Salmonella spp. were not found in autumn or winter, even though E. coli was detected in these seasons. Vibrio parahaemolyticus was found in autumn and winter, but not in spring. Norovirus genogroups I and II were found in winter samples. None of the bacteria were found in summer. Algal biotoxins have never been detected in mussel samples. Among potentially harmful phytoplankton, only Pseudo-nitzschia spp. were present, mainly in summer. The results showed that a possible bacterial and viral contamination, together with the presence of potentially toxic microalgae, is a real problem. Therefore, the development of natural resource management strategies is necessary to ensure the good quality of waters and guarantee the protection of consumers