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

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

Does Vitamin E or Vitamin E plus Selenium improve reproductive performance of rams during hot weather

The objective of this study was to determine the effect of Vitamin E (Vit E) and Selenium (Se) on semen quality, sexual activity, packed cell volume (PCV), and white blood cell counts (WBC) of Awassi rams during the hot season. Twelve Awassi rams were subdivided into three groups and treated for 90 days. Rams in the 1st group (T1) were treated twice weekly with 175 mg/ram vitamin E at intervals of 12h; rams in the 2nd group (T2) were treated on the same schedule with 70 mg/ram vitamin E plus 2800 mg selenium; and rams in 3rd group (T3) served as controls. Sperm quality (percentage of motile cells and percentage of morphologically normal cells) and quantity (sperm volume, and concentration) were recorded weekly. Sexual activity was tested by using the pen libido test at monthly intervals. Blood samples were taken before treatment and after the 1st, 2nd, and 3rd months. Semen quality was significantly affected by treatments: the ejaculate volume increased in T2 vs T1, and T3; mass activity and individual motility were increased in T1 and T2 vs T3. Sperm concentration was increased in T2 and T1 vs T3, and the percentage of dead and abnormal spermatozoa was reduced in T1 and T2 vs T3, though the differences were not statistically significant. Pen libido test showed reduced reaction time for the first mount in the 1st month in T2 and T1 vs T3. The number of serves was increased in groups T1 and T2 vs T3. There were no significant differences in PCV among groups. After 3 months from the beginning of treatments, the percentage of lymphocytes increased in T1 and T2 vs. T3, while the percentage of neutrophils was reduced in T2 vs T3 in the 2nd and 3rd months. The results of this experiment indicate that treatments with vitamin E alone or in combination with selenium improved semen characteristics and reproductive performance of Awassi rams during the hot season

Effects of fibre and non-fibre carbohydrate and level of intake on microbial protein yield in Sarda sheep

Three studies using Sarda dairy sheep in dry, mid-lactation and late-lactation were carried out. Forty ewes for each physiological stage were fed 8 complete pelleted diets, which differed from each other in NDF and NFC content and source. Based on their main ingredient, diets were denominated: corn meal (CM), wheat middlings (WM), corn flakes (CF), barley meal (BM), corn cobs (CC), beet pulp (BP), alfalfa (AA), and soybean hulls (SH). In each study, rumen microbial protein (MCP) synthesis was estimated measuring urinary purine derivatives. In dry sheep, MCP synthesis was not affected by diet, while in mid- and late-lactation sheep dietary effects were observed. In mid-lactation, the highest MCP production was found for BM and BP (171 and 166 g/d, respectively), while the lowest was observed with AA (63 g/d). In late-lactation, the highest MCP yield (146 g/d) was observed in BP, while the lowest were for SH and CM. MCP synthesis, for each diet, was higher in mid-lactation than in latelactation, which in turn were higher than in the dry period. Dry matter intake (DMI) was positively associated to MCP. The MCP synthesis was best predicted by dietary energy (NEL) or digestible organic matter intake (dOMI)

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

Does Vitamin E or Vitamin E plus Selenium improve reproductive performance of rams during hot weather?

The objective of this study was to determine the effect of Vitamin E (Vit E) and Selenium (Se) on semen quality, sexual activity, packed cell volume (PCV), and white blood cell counts (WBC) of Awassi rams during the hot season. Twelve Awassi rams were subdivided into three groups and treated for 90 days. Rams in the 1st group (T1) were treated twice weekly with 175 mg/ram vitamin E at intervals of 12h; rams in the 2nd group (T2) were treated on the same schedule with 70 mg/ram vitamin E plus 2800 mg selenium; and rams in 3rd group (T3) served as controls. Sperm quality (percentage of motile cells and percentage of morphologically normal cells) and quantity (sperm volume, and concentration) were recorded weekly. Sexual activity was tested by using the pen libido test at monthly intervals. Blood samples were taken before treatment and after the 1st, 2nd, and 3rd months. Semen quality was significantly affected by treatments: the ejaculate volume increased in T2 vs T1, and T3; mass activity and individual motility were increased in T1 and T2 vs T3. Sperm concentration was increased in T2 and T1 vs T3, and the percentage of dead and abnormal spermatozoa was reduced in T1 and T2 vs T3, though the differences were not statistically significant. Pen libido test showed reduced reaction time for the first mount in the 1st month in T2 and T1 vs T3. The number of serves was increased in groups T1 and T2 vs T3. There were no significant differences in PCV among groups. After 3 months from the beginning of treatments, the percentage of lymphocytes increased in T1 and T2 vs. T3, while the percentage of neutrophils was reduced in T2 vs T3 in the 2nd and 3rd months. The results of this experiment indicate that treatments with vitamin E alone or in combination with selenium improved semen characteristics and reproductive performance of Awassi rams during the hot season

Effects of short-term feed restriction on milk yield and composition, and hormone and metabolite profiles in mid-lactation Sarda dairy sheep with different body condition score

Ten Sarda dairy ewes (5 with high Body Condition Score: H-BCS, BCS>2.5; BW 48.8±5.4 kg; 5 with low BCS: L-BCS, BCS<2.5; BW 36.2±4.7 kg) were subjected, after 7-day preliminary (Prel) period, to short-term feed restriction (FR, 50% of nutrient requirements) for three days followed by refeeding (Re-Fed, 100% requirements) for three days. Milk yield and composition (protein, fat, lactose, MUN, SCC, fatty acids), and blood parameters (glucose, NEFA, BUN, insulin, GH, IGF-I, leptin) were monitored. Milk yield decreased during FR in both BCS groups: at day 3 it was 38% and 35% of Prel values in HBCS and L-BCS ewes, respectively, reaching Prel levels at Re-Fed in both groups. Milk fat concentration was influenced by BCS¥sampling, increasing in H-BCS ewes during FR, but not varying in L-BCS ewes throughout the trial. During FR, milk protein increased as milk yield decreased. There was no change in milk urea nitrogen concentration during FR, but this decreased in both BCS groups during Re-Fed. FR modified the FA profile of milk fat in both BCS groups, increasing LCFA at the expense of SCFA and MCFA. Some blood parameters (NEFA, GH and IGF-I) were influenced by BCS, whereas almost all parameters were influenced by sampling. There was a rapid return to initial levels in all parameters except milk urea, blood urea and insulin at Re-Fed

Rabbit meat production as affected by a delayed-weaning technique

Nowadays there is an increasing interest towards breeding systems, also for rabbit meat production, more mindful of animal welfare through an attenuation of the productive cycle intensity. These particular rearing techniques provide a delaying of the weaning age to reduce stress in young rabbits. The present research investigated the influence of weaning age on 192 crossbred rabbits (New Zealand White x Californian) divided in two experimental groups weaned at 28 (W28) and 63d (W63) respectively. From the statistical analysis significant differences emerged by comparing resulting data from W28 vs W63 rabbits, concerning productive parameters, commercial traits and composition of carcasses, meat chemical-nutritional characteristics

Pseudogestation et mortalité embryonnaire chez les chèvres Sarde et Saanen: étude préliminaire

Dans une communication précédente, nous avons rapporté les résultats d’une étude sur la pseudogestation (PG) chez la chèvre de race Sarde, qui se basait sur la concentration de PSPB (Pregnant Specific Protein B) mesurée 35 jours après la fin du traitement de synchronisation de l’oestrus et le diagnostic de gestation réalisé par échographie après 60 jours (Epifani et al., 2004). Toutefois, la chronologie des suivis et l’absence des données relatives à la progestérone plasmatique (P4) ne nous a pas permis de distinguer la PG de la mortalité embryonnaire (ME). Cette étude a eu pour objectif d’évaluer l’existence et l’incidence de la PG chez les chèvres élevées en Sardaigne, en la distinguant de la ME et de l’avortement (A)

Replacing chicken yolk with yolks from other sources in ram semen diluents and their effects on fertility <i>in vitro</i>

Over the past 70 years, egg yolk (EY) has been continuously used as a cryoprotectant in semen diluents. Earlier studies have shown that the composition of different EYs showed that the basic components were present in similar levels. However, further breakdown and analysis revealed significant differences between EY sources. The objective of this study was to evaluate and compare the effect of substitution chicken EY in ram semen diluents with yolks from other species on in vitro fertilization, subsequent embryonic development and total blastocysts formation. Through the breeding season, ejaculates were collected weekly from five Sarda breed rams of proven fertility, divided equally and diluted in Tris–citrate–fructose–glycerol based diluents containing 20% (v/v) of either partridge, ostrich, turkey, duck, tortoise, or chicken EYs (as a control) at 37 °C. Extended semen was cooled to 4 °C and preserved as a 0.25 mL pellet in LN2. Adults Sarda ewe ovaries were collected from a local slaughterhouse and a total of 913 collected oocytes were divided randomly and matured oocytes were fertilized in vitro with frozen–thawed spermatozoa prepared as described above, and cultured until Day 8. The proportions of cleaved and expanded blastocysts/groups were evaluating after 46, and 144–192 h post-insemination (hpi), respectively. Among all sources of EYs, semen cryopreserved in presence of partridge EY significantly increased the proportion of fertilized matured oocytes compared with semen preserved in presence of tortoise or chicken EYs (105/131, 80.1%), (74/123, 60.2%), and (189/270, 70.0%), respectively. Interestingly, using partridge, ostrich, turkey, and duck EYs in ram semen diluents increased significantly (P &lt; 0.001) the number of blastocysts formation on Day 6 after IVF versus tortoise or chicken yolks. However, there was no significant difference in total blastocysts yield between all sources of EY. In conclusion, the different compositions of yolks did offer different levels of in vitro production embryos. Specifically, semen diluents in presence of partridge yolks improved cleavage rates, and the numbers of early embryonic development. Whereas using ostrich, turkey, and duck EYs offered comparable fertilization and embryonic development versus conventional semen diluents with 20% chicken EY