Coat and hair color: hair cortisol and serotonin levels in lactating Holstein cows under heat stress conditions

The deleterious effects of heat stress on animal health are being increasingly recognized. This study aimed to determine hair cortisol (HC) and serotonin levels in lactating Holstein cows under heat stress conditions with different coat and hair‐cut color. Forty‐five multiparous lactating Holstein cows (days in milk = 130 ± 47, body weight = 753 ± 85 kg) were divided to two main groups of over 80% black coat color (BC) and over 85% white coat color (WC) visually observed based on registry certificates and subdividing to black hair sample (BH) and white hair samples (WH) in 2 × 2 factorial arrangements. Hair samples were taken from the forehead of the individuals. Higher HC levels were observed in BC than WC cows (P < 0.05). No differences were found in HC levels between BH and WH groups (P > 0.05). Serotonin levels showed no difference between BC and WC (P > 0.05). Interaction between coat color and hair color was not significant (P > 0.05). The cortisol levels in hair are not affected by pigmentation. However, pigmentation within the coat alters cortisol levels. In conclusion, white coat color retains less cortisol than the black coat. Therefore, white coats are preferable for dairy cows under heat stress conditions.     

Hair cortisol concentration in pre‐ and postpartum dairy cows,and its association with body condition,hock health,and reproductive status

The objective of this study was to investigate the profiles of hair cortisol concentrations as an index of chronic stress in dairy cows in association with their health, nutrition, and reproductive parameters. For 25 Holstein dairy cows, hair was collected from the tail switch ?19.2 ± 11.4, 44.8 ± 11.9, 103.0 ± 9.9, and 168.0 ± 9.7 days postpartum (L0, L1, L2, and L3, respectively). Body condition scores were negatively correlated with hair cortisol concentrations (r = ?0.255), and hock health scores were positively correlated with hair cortisol concentrations (r = 0.236, p < 0.05). Hair cortisol concentrations during the postpartum period showed different patterns according to the time of first artificial insemination (AI) and fertility. Cows that were submitted to first AI by 86 days postpartum showed a peak hair cortisol concentration at L1, whereas cows with delayed first AI had a peak at L2. The hair cortisol concentrations of subfertile (≥168 days) cows were significantly higher at L1 and L2 compared with L0, whereas hair cortisol concentrations of fertile cows (<168 days) were not different among the sampling times. These results indicate that cows with health problems appear to experience greater chronic stress, which may impair their reproductive function.     

Effect of growth and parturition on hair cortisol in Holstein cattle

The effect of growth and parturition on hair cortisol concentrations of cattle was investigated. Plasma, saliva, and hair (black and white from the shoulders and hip) samples were collected from calves at 6 and 24 weeks old and from dairy cattle at the dry (1 and 2 months prepartum) and lactation (10, 50, 150, and 250 days postpartum) periods. Plasma and saliva cortisol concentrations were lower in 24-week-old calves than those of 6-week-old calves, and hair cortisol concentrations decreased regardless of color and position. In 6-week-old calves, hair cortisol concentrations differed between sampling positions, but this difference was not observed in 24-week-old calves. Plasma and saliva cortisol concentrations increased before parturition until 10 days postpartum then decreased until 50 days postpartum. The same trend was observed in the cortisol concentrations of white hair. Contrarily, cortisol concentrations in black hair remained unchanged and was lower than that in white hair. Hair cortisol concentration can vary greatly depending on the location on the body, hair color, cattle age, or parturition. When this method is used, all of the above factors must be considered.     

Hair cortisol levels of lactating dairy cows in cold‐ and warm‐temperate regions in Japan

We compared the hair cortisol levels of lactating dairy cows in a cold‐ and a warm‐temperate region out of four climatic zones in Japan. We simultaneously investigated the effects of calving number, lactation period and month of hair sampling. Hair of nine Holstein lactating cows chosen from each region (i.e. 18 cows per sampling) was sampled in March, June, September and December. Number of calvings (1, 2, ≥3) and lactation duration (early: <100, middle: 101–200, and late: >201 days) were balanced between regions. Cortisol was extracted from hair by methanol, and its level was determined with a cortisol immunoassay kit. A multi‐way analysis of variance revealed that the effects of month of hair sampling (P < 0.001) and its combination with region (P < 0.05) were significant. In a multiple comparison test, significant differences (P < 0.01) in hair cortisol level (pg/mg of hair) were found between June (13.0 ± 1.0) and the other 3 months, and between September (1.6 ± 0.2) and December (4.5 ± 0.3). The rise in cortisol level from March to June was more intense in the cold‐temperate region. These results demonstrate the necessity of considering seasonal variations in each climatic region when we use hair cortisol level as an indicator of stress.     

Association of increased serum acute‐phase protein concentrations with reproductive performance in dairy cows with postpartum metritis

Background: It is known that quantification of bovine acute‐phase proteins could routinely provide early diagnostic and prognostic information for monitoring herd health status. Objective: The aim of this study was to test the hypothesis that haptoglobin (Hp) and serum amyloid A (SAA) have the potential for indicating uterine infection, mainly due to subclinical endometritis, which can seriously influence the reproductive performance in dairy cows. Methods: A total of 264 serum samples were collected from 24 Holstein dairy cows at defined intervals from 1 week prepartum to 6 months postpartum. Clinically healthy animals (Group 1, n=6) were compared with 24 animals having acute puerperal metritis (Group 2, n=18) and with concentrations obtained from healthy heifers (baseline values, n=10). The concentrations of serum Hp and SAA were measured using a hemoglobin‐binding assay and Western blot analysis, respectively. Reproductive performance was assessed as the number of days open and the conception rate at the end of the study. Results: Upper cut‐off values for Hp and SAA concentrations in heifers were 130.9 μg/L and 51.9 μg/mL, respectively. Hp concentrations in Group 2 were significantly higher than those in Group 1 at all time points (P<.001). Additionally, among the successfully pregnant animals, the number of days open was significantly higher in 6 cows with Hp >130.9 μg/mL (median=316 days) than in 11 cows with Hp ≤130.9 μg/mL (median=120 days) (P=.0024). Conclusions: Serum Hp and SAA concentrations can be used to recognize uterine infection in postpartum cows. The association between elevated Hp values and number of days open suggests Hp may also be a useful indicator of poor prognosis for reproductive performance.     

Evaluation of the potential effects of abortion on the productive performance of Iranian Holstein dairy cows

Calving records from the Animal Breeding Center of Iran collected from January 1983 to December 2007 and comprising 1 163 594 Holstein calving events from 2552 herds were used to evaluate the potential effect of abortion occurrence on 305‐day milk yield, milk fat yield, fat percentage of milk and milk protein yield in Iranian Holsteins. Statistical analyses of production traits were performed using a linear mixed model procedure. Normal‐calved cows had greater 305‐day milk production, fat yield and protein yield of milk than abortive‐calved cows (P < 0.05). However, abortive‐calved cows had the greater milk fat percentage than normal calved cows (P < 0.05). The linear and quadratic effects of age of dam were significant on all of the studied traits (P < 0.05). The results of regression analysis showed that increase in the quadratic effect of age can cause an increase in the fat percentage of milk for all calvings including normal and abortive calvings. Because abortion is one of the most important conditions that limit a cow's ability to produce, maintaining the general health of cattle is important in minimizing the risk of abortion problems.     

Effect of dystocia on subsequent reproductive performance and functional longevity in Holstein cows

The objective of this study was to evaluate the effect of dystocia on the reproductive performance and functional longevity in Iranian Holsteins. Data consisted of 1 467 064 lactation records of 581 421 Holstein cows from 3083 herds which were collected by the Animal Breeding Center of Iran from April 1987 to February 2014. Reproduction traits in this study included interval from first to second calving, days open and days from first calving to first service. The generalized linear model was used for the statistical analysis of reproductive traits. Survival analysis was performed using the Weibull proportional hazards models to analyse the impact of dystocia on functional longevity. The incidence of dystocia had an adverse effect on the reproductive performance of dairy cows. Therefore, reproductive traits deteriorated along with increase in dystocia score (p < 0.05). The culling risk was increased along with increase in the score of dystocia (p < 0.0001). The greatest culling risk was observed in primiparous cows, small herds and low‐yielding cows (p < 0.0001). Also, the lowest culling risk was found for cows calving at the youngest age (<27 months), and cows with age at first calving >33 months had the greatest risk (p < 0.0001). The results of current study indicated that dystocia had important negative effects on the reproductive performance and functional longevity in dairy cows, and it should be avoided as much as possible to provide a good perspective in the scope of economic and animal welfare issues in dairy herds.     

繁殖营养素对西杂母牛繁殖性能、产后健康及犊牛生长性能的影响

摘要：［目的］探究繁殖营养素对西门塔尔杂交母牛繁殖性能、产后健康及犊牛生长性能的影响。［方法］试验对33头390kg左右妊娠8-9月的初配西门塔尔杂交母牛饲喂不同添加量的繁殖营养,对母牛繁殖性能、产后健康及犊牛生长性能的数据进行分析。［结果］饲喂10g/(头·d)繁殖营养素母牛人工助产率较对照组大幅降低,且犊牛成活率提高,犊牛发病率减少。第一次发情时间提前7.42d,且受胎率也有所提高;饲喂10g/(头·d)繁殖营养素大幅度降低了母牛胎衣不下、子宫炎和乳房炎疾病的发病率;添加了10g/(头·d)繁殖营养素组的犊牛从出生到产后3月龄,其体重和体尺都有不同程度提高。［结论］母牛日粮中添加10g/(头·d)繁殖营养素能提高母牛繁殖性能、降低母牛产后疾病的发生率以及一定程度上提高犊牛的生长性能。     

Effect of dietary chromium supplementation on productive and reproductive performance of early lactating dairy cows under heat stress

One hundred and twenty early lactating Holstein dairy cows were assigned to investigate the effect of dietary chromium (Cr) supplementation (0 or 6 mg Cr/head/day from organic preparation) on the productive and reproductive performance as well as on some blood serum parameters under heat stress (35–40 °C). Cows received treatment from 3 weeks pre‐partum through 12 weeks post‐partum. Chromium supplemented diet had lower body weight loss and improved dry matter intake with consequent reduction in the energy balance deficits during the first period after calving when compared with the control group. Chromium supplementation increased (p < 0.05) milk yield by 6.7%, 12.3% and 16.5% at 4, 8 and 12 weeks post‐partum, respectively, whereas milk composition and milk to feed ratio were unaffected (p > 0.05) when compared with the control. Moreover, dietary Cr supplementation had no effect (p > 0.05) on blood serum glucose, calcium and phosphorus concentrations. A reduction (p < 0.05) of non‐esterified fatty acids at 1 week pre‐partum, 2 and 4 weeks post‐partum was also observed. Serum insulin concentration increased whereas cortisol concentration decreased, when compared with the control group, throughout the whole experimental period. Also Cr supplementation showed a trend towards improving reproductive performance as indicated by increased percentage of pregnant cows in the first 28 days of breeding. It could be concluded that dietary Cr supplementation at level of 6 mg/head/day may offer a potential protective management practice to lessen the effect of heat stress in dairy cattle.     

Ameliorative effects of oral ginger and/or thyme aqueous extracts on productive and reproductive performance of V‐line male rabbits

The objective of this study was to determine the impact of ginger and/or thyme aqueous extracts administration on the growth rate, caecum activity, reproductive performance and semen quality of rabbits. A total of 24 V‐line male rabbits at the age of 12 weeks were divided randomly into four equal groups (6/each) until 24 weeks of age. Treatments were as follows: drinking fresh water and served as control (G1); drinking water supplemented with 100 mg/kg b. wt. of ginger aqueous extract (G2); drinking water supplemented with 50 mg/kg b. wt. of thyme aqueous extract (G3); drinking water supplemented with 100 mg/kg b. wt. of ginger aqueous extract plus 50 mg/kg b. wt. of thyme aqueous extract (G4). Administration of aqueous thyme extract with 50 mg/kg b. wt. improved (p < 0.001) feed intake and growth performance compared to control. The highest average daily gain (p < 0.001) was found for G3 rabbits followed by G4, G2 and G1 respectively. While the most efficient feed conversion ratio was found in G4. Group 3 and group 4 had significant (p < 0.05) positive effect on caecum pH, ammonia and TVFAs concentration. Data indicated that treated groups had hastened the age with heavier body weight, larger testicular size and higher testosterone level. Also, most semen characteristics (volume, progressive motility, sperm concentration and normal spermatozoa) were higher in treated groups compared with the control group. Furthermore, gathering of the spermatozoa in the lumen of the seminiferous tubules, expanded epithelial cells stature of the epididymis with stuffed lumens with sperms in treated groups. In conclusion, aqueous extracts of ginger and/or thyme can be used as a growth promoter for improving reproductive performance of V‐line male rabbits.     

Effects of phyto‐oestrogen quercetin on productive performance,hormones, reproductive organs and apoptotic genes in laying hens

Quercetin, a polyphenolic flavonoid with diverse biological activities including anti‐inflammatory and antiviral, inhibits lipid peroxidation, prevents oxidative injury and cell death. The purpose of the research was to investigate the effect of quercetin on productive performance, reproductive organs, hormones and apoptotic genes in laying hens between 37 and 45 weeks of age, because of the structure and oestrogenic activities similar to 17β‐oestradiol. The trial was conducted using 240 Hessian laying hens (37 weeks old), housed in wire cages with two hens in each cage. These hens were randomly allotted to four treatments with six replicates, 10 hens in each replicate and fed with diets containing quercetin as 0, 0.2, 0.4 and 0.6 g/kg feed for 8 weeks. The results showed that dietary quercetin significantly increased (p < .05) the laying rate and was higher in group supplemented with 0.4 g/kg, and feed‐egg ratio was decreased (p < .05) by quercetin. Dietary quercetin has no effect (p > .05) on average egg weight and average daily feed intake. Compared with control, secretion of hormones, oestradiol (E₂)_, progesterone (P4), follicle‐stimulating hormone (FSH), luteinizing hormone (LH), insulin‐like growth factors‐1 (IGF‐1) and growth hormone (GH), was found to be significantly higher (p < .05) in quercetin‐supplemented groups. Also ovary index, uterus index and oviduct index were not significantly influenced (p > .05) by quercetin, whereas magnum index, isthmus index, magnum length, isthmus length and follicle numbers were significantly increased (p < .05) with quercetin supplementation. Additionally, expression of apoptotic genes was significantly (p < .05) up‐regulated or down‐regulated by quercetin. These results indicated that quercetin improved productive performance, and its mechanism may be due to the oestrogen‐like activities of quercetin.     

Seasonality in resumption of ovarian activity and reproductive performance of postpartum Holstein cows

It has been suggested that domestication has turned cattle from seasonal breeders to annual breeders. This study examined the seasonal differences in early postpartum ovulation and subsequent reproductive performance in 542 Holstein cows. Cows displaying corpora lutea in the ovary at 26 days postpartum were defined as early ovulators. Factors affecting the occurrence of early ovulation were analyzed, and subsequent reproductive traits were compared between cows with and without early ovulation. During the summer season, 70.6% of calving cows showed early ovulation, whereas 48.7, 39.2, and 47.2% presented this condition in autumn, winter, and spring, respectively (P < 0.01). Third parity cows showed early ovulation more often than their first parity counterparts (P < 0.05). Cows with a 2.50 to 3.00 or > 3.00 body condition score (BCS) more frequently became early ovulators than those with BCSs < 2.50 (P < 0.01). Calving year was a risk factor, and uterine abnormalities were also often risk factors for early ovulation. The survival analysis showed that seasonal differences in the occurrence of early ovulation did not completely affect the time to first service and pregnancy. Proportional hazard regression analysis revealed that calving year, parity, and early ovulation were risk factors for the time to first service and that calving year was a risk factor for the time to pregnancy. In conclusion, domesticated dairy cows maintain seasonality in postpartum ovarian activity but not in subsequent fertility.     

Modulation of post‐partum reproductive performance in dairy cows through supplementation of long‐ or short‐chain fatty acids during transition period

Thirty‐six cross‐bred cows were used to study the effect of long‐chain (flaxseed) or short‐chain (butyric acid) fatty acid supplementation on metabolic status, ovarian function and reproduction performance during transition period. Control cows received a routine feed of transition diet, while the cows in two treatment groups were supplemented with either 750‐g crushed flaxseed or 250 g butyric acid per cow per day. Ovarian activity was monitored by transrectal ultrasonography on 10th, 20th and 30th days post‐partum. Blood samples were collected by jugular venipuncture into heparinized polystyrene tubes; plasma was prepared and stored under ?20 °C until analysis. Results indicated that cows in flaxseed group were in positive energy balance as indicated by lower NEFA and Beta hydroxy Butyrate and higher glucose concentrations. Uterine involution was completed well within 30 days post‐partum in all the cows in flaxseed fed group compared to 76.9% in butyric acid supplemented and 61.5% in control groups. The size of dominant follicle and corpus luteum was significantly higher (p < 0.05) for flaxseed group compared to control group, which in turn resulted in higher concentrations of plasma progesterone. Cows fed on diets supplemented with flaxseed exhibited post‐partum heat earlier and bred sooner (p < 0.05) than control cows. It has been noticed that supplementation of flaxseed and butyric acid enhanced involution of uterus, early resumption of cyclicity and thereby early breeding. However, in view of the encouraging results obtained for flaxseed supplemented group, its organic nature and easier availability at farmer's gate, we concluded that flaxseed can be safely included in transition diet to modulate reproductive performance of dairy cattle.     

The effect of modified roofing on the milk yield and reproductive performance of heat‐stressed dairy cows under hot‐humid conditions

The objective was to measure the effects of cooling techniques (shade cloth vs. normal roof) on performance and physiology of 16 Friesian crossbred cows (87.5% Holstein Friesian × 12.5% Brahman) located at Sakol Nakhon Livestock Research and Testing Station, Department of Livestock Development, Ministry of Agriculture and Cooperatives (Sakol Nakhon, Thailand). They were divided randomly into two groups of eight. The two groups were used to evaluate the effects of modified roofing (normal roof fitted with woven polypropylene shade cloth) on the subjects' milk yield and reproductive performance under hot humid conditions. Results indicated that the modified roofing offered a more efficient way to minimize heat stress than the normal roof. The difference was sufficient to enable the cows to have a significantly lower mean rectal temperature and respiration rate (38.56°C, 61.97 breaths/min) than that of the cows housed under normal roofing (39.86°C; 85.16 breaths/min). The cows housed under modified roofing produced more milk (P < 0.05) but did not differ significantly in reproductive performance from the cows housed under normal roofing.     

Evaluation of vaginal discharge with the Metricheck device and the relationship to reproductive performance in postpartum dairy cows

Vaginal mucus during estrus was examined with the Metricheck device and the relationship to the reproduction of high‐yielding dairy cows was studied. The study was conducted in 99 dairy herds located in Western Germany and 1348 Holstein‐Friesian heifers and cows showing spontaneous estrus were examined. Independent of the Metricheck result, the animals were inspected by professional insemination technicians and those suitable for insemination (n = 989) were bred by artificial insemination (AI). Reproductive performance was characterized by non‐return rate at 90 days (NRR90). The discharge of the animals predominantly had a clear appearance (70%) and a stringy consistency (80%). Animals with clear vaginal discharge had higher NRR90 (56%; n = 697) than animals with abnormal (turbid, mucopurulent, purulent, sanguineous) vaginal secretion (48%, n = 292; P < 0.05). NRR90 was lower in animals with short calving to AI interval (< 70 days; 39%) than with medium (70–130 days; 54%) or long (> 130 days; 62%) intervals (P < 0.05). NRR90 decreased by 12% from the lowest (< 15 kg) to the highest (> 45 kg) milk yield class. In conclusion, the use of the Metricheck device integrated into the insemination procedure is recommended to identify dairy cows suffering severely from uterine disease.     

Evaluation of high nutrient diets and additional dextrose on reproductive performance and litter performance of heat‐stressed lactating sows

This study investigated the litter performance of lactating sows fed nutrient‐dense diets with or without dextrose at farrowing to weaning, during the summer with an average room temperature of 28.4°C. A total of 60 (13 first parity, 13 second parity, 19 third parity, and 15 forth parity) cross‐bred sows were assigned to three treatments. The three treatments were: standard diet (ST), high nutrient diet (HN; ST + 3% higher energy and 18.0% protein), and high nutrient diet plus dextrose (HND; 3% higher energy, 18.0% protein, and 5% dextrose). BW loss was reduced in the HND sows compared with the ST sows during lactation. The HN and HND sows had a higher piglet and litter weight at weaning. Also, the HND sows had the highest post‐prandial insulin levels at weaning and the shortest weaning‐to‐service interval (WSI). Serum LH was higher in the HND sows than the ST sows. The milk fat level was higher in the HND sows compared with the ST sows, but similar to the HN sows. In conclusion, these results suggest that it is possible to increase the blood insulin response by supplementing dextrose to a high nutrient diet, thus, improving WSI interval and litter growth during heat stress.     

Effect of induced body condition score differences on physiological response,productive and reproductive performance of Malpura ewes kept in a hot,semi‐arid environment

This study was undertaken to study the influence of induced body condition score (BCS) differences on physiological response, productive and reproductive performance of Malpura ewes to optimise BCS for these ewes for maximising production making it economically viable. The study was conducted for a period of 1 year using thirty healthy Malpura ewes (2–4 year old). The animals were randomly divided and different BCS was induced within three groups named Group I (BCS 2.5; n = 10), Group II (BCS 3.0–3.5; n = 10) and Group III (BCS 4.0; n = 10). The parameters included in the study were allometric measurements, physiological response, wool yield and reproductive performance. BCS had a significant influence on allometric measurements, respiration rate and different reproductive parameters studied, while wool production differed significantly during spring and non‐significantly during autumn. The results revealed that the reproductive performance of Malpura ewes with a BCS of 3.0–3.5 was better in comparison with the groups with lower and higher BCS. It may be concluded from this study that an active management of breeding sheep flock to achieve a BCS of 3.0–3.5 may prove to result in an economically viable return from these flocks.     

Performance,body fat reserves and plasma metabolites in Brown Swiss dairy cows: Indoor feeding versus pasture‐based feeding

Feeding dairy cows indoors or on pasture affects not only labour, machinery and housing costs, but also animals’ performance and metabolism. This study investigates the effects of indoor feeding (IF) with a partial‐mixed ration (PMR) versus pasture‐based feeding (PF) on milk production, fertility, backfat thickness (BFT), body weight (BW) loss and energy metabolism of Brown Swiss (BS) dairy cows with similar genetic production potential. The IF herd consisted of 13 cows fed a PMR composed of maize and grass silage plus protein concentrate according to each cow's requirements. The PF herd consisted of 14 cows offered barn‐ventilated hay ad libitum after calving from January until March and grazed on semi‐continuous pastures during the vegetation period. The IF cows produced more energy‐corrected milk (ECM) per standard lactation (9,407 vs. 5,960 kg; p < .01), more milk fat (378 vs. 227 kg; p < .01) and milk protein (326 vs. 215 kg; p < .01). The calving interval (377 vs. 405 days; p < .01) and time empty (86 vs. 118 days; p < .01) were shorter in the PF compared to IF, possibly also due to different selection criteria for maintaining the respective seasonal calving rhythm. The empty body fat loss calculated according to BCS until its nadir was higher in IF cows (IF: 10.4 vs. PF: 4.8 MJ/day; p < .01), but no differences were noted in total body fat loss estimated via BFT (p = .24). However, PF had lower blood glucose concentration at all investigated time points, but no differences occurred in serum non‐esterified fatty acid and β‐hydroxybutyrate concentrations post‐partum. In conclusion, BS cows were equally well suited for the IF with PMR and the PF system investigated here without developing a prominent metabolic load despite differences in nutrient supply. As such, investigated BS dairy cows in our trial seem to have a high capacity for metabolic adaptation to different production systems.     

Initial cooling time before freezing affects post‐thaw quality and reproductive performance of rabbit semen

The aim of this study was to investigate the effect of initial cooling time at 5°C during semen cryopreservation on post‐thaw quality and reproductive performance of rabbit semen. Pooled semen samples (n = 6) were divided into two subsamples and cooled at 5°C for 45 or 90 min. After cooling, the semen samples were diluted to a ratio of 1:1 (v:v) with a freezing extender composed of Tris‐citrate‐glucose (TCG) containing 16% of dimethylsulfoxide and 0.1 mol/L sucrose. The semen was subsequently loaded in 0.25 ml straws, equilibrated at 5°C and frozen in liquid nitrogen vapor. After thawing, sperm motility, viability, osmotic resistance, acrosome and DNA integrity were assessed. Our results indicate that the longer cooling time, that is, 90 min before cryopreservation significantly improves sperm post‐thaw viability, motility and fertility. In fact, reproductive performances obtained with semen frozen after a 90 min cooling time were similar to those produced by fresh semen insemination. Hence, the present research provides an effective freezing protocol for rabbit semen that will allow for the creation of a sperm cryobank for the conservation of Italian rabbit genetic resources, as well as the use of frozen semen doses in commercial farms.