Nutritional supplementation improves the sexual response of bucks exposed to long days in semi-extensive management and their ability to stimulate reproduction in goats

In confined management systems, well-nourished bucks rendered sexually active by exposure to long days are efficient in fertilizing out-of-season goats. However, underfeeding is common in semi-extensive management systems and may reduce the reproductive efficiency of bucks. The objective of the present study was to determine whether nutritional supplementation improved the sexual activity of bucks submitted to long days in semi-extensive management systems and their ability to stimulate the reproduction of goats in semi-extensive or confined conditions. In experiment 1, three groups of bucks were placed in different flocks and grazed daily with females for 7 h. Each day after grazing, males were separated from females and moved into open pens. One group did not receive any treatment (control group; n = 6). Two other groups were submitted to artificially long days from 15 November to 15 January. From 16 January, one group did not receive nutritional supplementation (long-day group; n = 5), whereas bucks from the other group each received 600 g of a commercial concentrate (long-day + supplementation group; n = 5). The fourth group was kept in confined conditions, exposed to long days and fed alfalfa hay (long-day confined group; n = 6). On 26 March, anovulatory goats from other flocks were assigned to four groups (n = 27 each) and confined separately in open pens. Three bucks of each group were housed with the females. Pregnancy rates were greater in the goats housed with the long-day group than those housed with the control group (P < 0.01). However, pregnancy rates did not differ between the long-day confined group (89%) and long-day + supplementation group (70%; P = 0.09), but these rates were greater than those from the long-day (37%) and control groups (0%; P < 0.05). In experiment 2, two groups of males (n = 3 each) were incorporated into two flocks under semi-extensive management and grazed daily with females for 7 h. One group of males did not receive any treatment (control group). The other group was submitted to long days and nutritional supplementation as in experiment 1 (long-day + supplementation group). Males remained with females during the whole study. The pregnancy rate was greater in the goats joined by males of the long-day + supplementation group (78%) than in those from the control group (0%; P < 0.001). We conclude that long days and nutritional supplementation improve the ability of bucks kept in semi-extensive management to stimulate reproduction of out-of-season goats in confined or semi-extensive management systems.     

Effects of groundnut stover or Bermudagrass hay supplementation to doe kids on winter hardwood range

Goats in north-central Texas raised on rangeland often face winter forage quantity and quality deficits that may be mitigated by feeding hay or stover. Groundnut (Arachis hypogea) stover (8% CP, 35% ADF, 43% NDF and 8% acid detergent lignin (ADL) DM basis) and bermudagrass (Cynodon dactylon) hay (12% CP, 33% ADF, 73% NDF, and 5% ADL DM basis) were tested at Stephenville, Texas as 0.0, 0.5, or 2.0% BW supplement/substitution diets on 18 kg Boer X Spanish doe kids browsing native hardwoods (8 ha⁻¹). Both hay and stover were fed ad libitum in a traditional feedlot, using a complete formulated feed ration as a control. Trials ran for 10 weeks from January to March in 2003 (134 mm rainfall) and in 2004 (182 mm rainfall). Goats receiving 0.5% and 2% BW bermudagrass or 2% BW groundnut stover had greater ADG than those in the control and 0.5% BW groundnut paddocks (P < 0.05). Goats fed complete ration in the drylot had greater (P < 0.05) ADG than those eating either hay or stover ad libitum. Bermudagrass hay rejected by goats in the hardwood trial was 20% lower in CP, 7% greater in NDF, 8% greater in ADF, and 9% greater in ADL than the original fed hay; groundnut stover refusals were 21% lower in CP, 12% greater in NDF, 19% greater in ADF, and 20% greater in ADL concentration than the stover when fed. Supplementing goats on hardwood range with bermudagrass hay or groundnut stover may improve ADG when browse is scarce or of poor quality.     

Comparative studies on dry matter intake,digestibility and nitrogen metabolism between Thai native (TN) and Anglo Nubian × TN bucks

Metabolic experiments were conducted for each Thai native (TN) and Anglo Nubian–TN 50% (AN × TN) bucks, 26.5–38 kg BW and 35–52 months of age, by assigning the following concentrate diets, which had four levels of CP concentrations, T1: 14%, T2: 21%, T3: 28% and T4: 35%, on a DM basis. The animals were fed the concentrates at a rate of 1% of their BW and had ad libitum access to Paspalum plicatulum hay. As the CP level increased, digestibility of CP, N excretion in urine and N retention increased (P < 0.01). No significant differences of DM digestibility among the CP levels of diet and between the breeds of bucks were observed. The AN × TN had higher DM intake than TN (P < 0.05, 40.9 g/(kg BW^0.75 day) versus 36.0 g/(kg BW^0.75 day)), thus N intake of AN × TN was higher than that of TN (P < 0.01, 0.99 g/(kg BW^0.75 day) versus 0.90 g/(kg BW^0.75 day)). Digestibility of CP and blood urea N concentrations of TN were higher than those of AN × TN (P < 0.05, 69.8% versus 64.0% and 32.2 mg/dl versus 26.7 mg/dl, respectively). The AN × TN tended to retain more N than TN in the higher CP feeding condition of T3 (0.19 g/(kg BW^0.75 day) versus 0.11 g/(kg BW^0.75 day)) and T4 (0.25 g/(kg BW^0.75 day) versus 0.17 g/(kg BW^0.75 day)). Digestibility of NDF and ADF, and TDN of TN were higher than those of AN × TN (P < 0.05, 61.1% versus 55.9%, 49.6% versus 43.5% and 65.8% versus 62.4%, respectively). The overall mean DE was 109 kcal/(kg BW^0.75 day), and no significant difference of DE among CP levels nor breeds of bucks was observed. Thai native was superior to AN × TN in digestibility of N and fiber fractions at the maintenance level of DE, which might have overcome inferiority of TN to AN × TN in amount of N and energy intake caused by the lower DMI. It is likely that TN goats are well adapted to fodder shortage condition due to their efficient utilization of nutrients.     

Flaxseed oil modulates testicular biometrics,hormone, libido,antioxidant and semen profiles in endangered Teressa goat of Andaman and Nicobar Islands

Teressa goat is a unique goat breed in Andaman and Nicobar Islands (ANI) of India. Effects of Flaxseed oil (FSO) supplementation in body weight (BW), scrotal circumference (SC), testicular volume (TV) and testicular weight (TW), endocrinological profiles, sex behavioural profiles (SBPs), oxidative stress markers and semen production and its quality profiles in rainy and dry summer season were studied in Teressa goat. Male goats (n = 12) of 3–4 years old were equally divided into control and treated groups. Treated animals received 25 mL FSO per day. Oral drenching of FSO was done in the morning before feeding the concentrate ration. Body weight, scrotal circumference, TV and TW were measured in bucks of FSO treated and untreated during rainy and dry summer seasons. Blood follicle stimulating hormone (FSH), luteinizing hormone (LH), testosterone, thyroid stimulating hormone (TSH), triiodothyronine (T3), thyroxine (T4), cortisol and prolactin, total antioxidant capacity (TAC), superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and malondialdehyde (MDA) were measured in bucks of FSO treated and untreated during rainy and dry summer seasons. Libido score (LS), mating ability score (MAS) and sex behavioural score (SBS) were estimated at time of semen collection in bucks of FSO treated and untreated during rainy and dry summer seasons. Semen samples (n = 100; 50 semen samples from each season; each 25 semen samples from control and treatment groups per season) were collected and analysed for semen quality profiles. One-way ANOVA (control rainy, control dry, treated rainy and treated dry) revealed that BW, SC, TV and TW, FSH, LH, testosterone, TSH, T3 and T4 were higher (P < 0.05) and cortisol and prolactin were lower (P < 0.05) in FSO treated bucks of rainy season followed by untreated bucks of rainy season, FSO treated bucks of dry summer season and were lower (P < 0.05) in untreated bucks of dry summer season. Similarly, TAC, CAT, SOD and GSH, LS, MAS and SBS, and volume, pH, sperm concentration, mass activity, total motility (TM), viability, acrosomal integrity (AcI), plasma membrane integrity (PMI) and nuclear integrity (NI) were higher (P < 0.05) and MDA and TSA were lower (P < 0.05) in FSO treated bucks of rainy season followed by FSO treated bucks of dry summer season, untreated bucks of rainy season and were lower (P < 0.05) in untreated bucks of dry summer season. The results of the present study indicated that the breeding bucks suffered physiological stress (higher cortisol), oxidative stress (higher MDA and deficiency of antioxidants), hormonal imbalance (higher prolactin and cortisol and deficiency of gonadotropins, gonadal hormone and thyroid hormones) and infertility due to poor libido and poor semen production and its quality profiles during dry summer season. Thus, dry summer was more stressful season compared to rainy season for the goat bucks. FSO supplementation mitigated these stresses and improved the scrotal and testicular biometrics, libido, antioxidants, hormones and semen quality profiles in Teressa goat bucks. The current study concluded that FSO effectively improved the hormones, libido, antioxidant profiles, and scrotal and testicular biometrics with cascading beneficial effects on semen quality profiles in Teressa goat bucks under humid tropical island ecosystem of Andaman and Nicobar Islands.     

Efficiency of energy use for maintenance and gain by growing crossbred Boer and Spanish Goats consuming diets differing in forage level

Eight Boer (75%) × Spanish (BS) and eight Spanish (S) wether goats (155 ± 8 days of age and 19.2 ± 2.3 kg BW, initial) were used in a replicated crossover design experiment with a 2 × 2 factorial arrangement of treatments to determine the effects of genotype and diet quality on heat production with ad libitum, near maintenance and fasting levels of feed intake. Diets were 65% concentrate (CON 15% CP, DM basis) and coarsely ground alfalfa hay (FOR 23% CP). There were no significant interactions between genotype and diet. ME intake was similar between genotypes and greater (P < 0.05) for CON versus FOR both when intake was ad libitum (7.60 versus 5.43 MJ/day) and near maintenance (4.31 versus 4.09 MJ/day). DE concentration was greater (P < 0.05) for CON than for FOR with ad libitum (74.4 versus 55.5%) and restricted intake (77.0 versus 59.6%). Energy expenditure (EE), determined by respiration calorimetry, at all levels of intake was similar between genotypes. EE was greater (P < 0.05) for CON than for FOR at each of the three levels of intake, ad libitum (573 and 521 kJ/kg BW^0.75 while fasting), near maintenance (426 and 400 kJ/kg BW^0.75) and fasting (280 and 255 kJ/kg BW^0.75). Efficiencies of ME utilization for maintenance (k_m) and gain (k_g) and the ME requirement for maintenance (ME_m) were similar between genotypes. k_m was similar between diets (0.705 and 0.690 for CON and FOR, respectively), although k_g was greater (P < 0.05) for CON than for FOR (0.603 versus 0.387). ME_m was numerically greater (P < 0.17) for CON than for FOR (407 versus 379 kJ/kg BW^0.75), which may have involved higher ME intake with CON. In conclusion, under the conditions of this experiment energy requirements and efficiency of utilization were not different between growing Boer crossbred and Spanish goats regardless of diet quality.     

Effects of total nonstructural carbohydrates and nitrogen balance on voluntary intake of goats and digestibility of gamagrass hay harvested at sunrise and sunset

We evaluated differences in composition of Iuka gamagrass (Tripsacum dactyloides L.) hay harvested at 06:00 (AM harvest) or 18:00 h (PM harvest), and measured how protein supplementation and time of harvest interact to affect the voluntary intake, digestibility, and N balance of goats. Boer cross wethers (n = 28; 24 kg) were randomly assigned to be fed supplement (310 g/kg of crude protein (CP), fed at 110 g/kg of dry matter (DM) intake, 14 goats) or no supplement (14 goats). Within supplemented or not supplemented groups, goats were randomly assigned to a crossover design of AM harvest (seven goats) or PM harvest (seven goats), and housed individually in metabolism crates with free access to water and mineral blocks. They were fed twice daily, with supplement offered 30 min prior to the morning feedings. After a 7-d adaptation, voluntary intake (goats were offered 1100 g/kg of previous day's intake) was measured for 14 d, followed by a 4-d adjustment phase to equalize DM offered between periods, and finally a 5-d digestion and balance phase. After Period 1, goats were switched to their new hay harvest times, and the protocol was repeated. Compared to the AM harvest, the PM harvest had higher (P<0.03) proportions of total nonstructural carbohydrates (TNC, 70.8 g/kg DM versus 59.0 g/kg DM), monosaccharides (37.0 g/kg DM versus 28.6 g/kg DM), di- and polysaccharides (18.5 g/kg DM versus 15.4 g/kg DM) and less neutral detergent fiber (NDF, 700 g/kg versus 710 g/kg). Crude protein (79 g/kg DM) and starch (15.2 g/kg DM) were similar for the PM and AM harvest. Dry matter digestibility was higher (P<0.03) for the PM versus AM harvests (555 g/kg DM versus 531 g/kg DM) and for supplemented versus not supplemented (563 g/kg DM versus 522 g/kg DM). Voluntary gamagrass DM intake (550 g/d versus 548 g/d) and calculated total digestible DM intake (327 g/d versus 313 g/d) were similar for the PM and AM harvest. However, total digestible DM intake during the digestion and balance phase was higher (P<0.01) for the PM versus AM harvest (317 g/d versus 299 g/d). Time of harvest did not affect N intake, digestion, or calculated retention. Compared to no supplementation, the supplement improved (P<0.01) N digestion (6.1 g/d versus 3.7 g/d) and retention (2.2 g/d versus 1.1 g/d). The PM harvest increased DM digested, largely TNC and digestible DM intake by goats due to increased TNC and not because of a 2% increase in DM intake. Providing a protein supplement had very limited effects on intake and digestibility of gamagrass.     

The effect of GnRH,eCG and progestin type on estrous synchronization following laparoscopic AI in ewes

The aim of the experiment was to evaluate the effects of GnRH and/or eCG and progestin type (implant versus CIDR) on the induction of estrus and pregnancy rate following laparoscopic AI (LAI) with frozen semen. In the first trial, ewes (n = 129) were treated with norgestomet implants for 14 days. At implant removal ewes received eCG (400 IU) and/or GnRH (25 μg) 36 h after removal, resulting in control, eCG, GnRH, and eCG/GnRH groups (n = 30–34/group). In trial 2, ewes (n = 36) were treated with intravaginal fluorogestone acetate sponges (FGA) or CIDR for 12 days. After withdrawal, half of the ewes from each progestin group received eCG (400 IU), resulting in sponge, sponge/eCG, CIDR and CIDR/eCG groups (n = 8–10/group). In both trials, estrous activity was assessed using a vasectomized ram from the time of progestin removal to laparoscopic AI with frozen semen 58–60 h (trial 1) or 54–56 h (trial 2) following cessation of treatment. In trial 1, GnRH decreased (P < 0.05) the percentage of ewes in estrus (GnRH, 75.8% versus control, 93.8% versus eCG/GnRH, 94.1%), however pregnancy rates were similar in all groups (control, 53.1%; eCG, 70.0%; GnRH, 51.5%; eCG/GnRH, 55.9%, respectively). In trial 2, neither the type of progestin nor eCG treatment effected the percentage of ewes in estrus (sponge, 75.0%; sponge/eCG, 100.0%; CIDR, 100.0%; CIDR/eCG, 90.0%). However, pregnancy rates following LAI were higher (P < 0.05) when ewes were treated with eCG (progestin + eCG, 73.7% versus progestin alone, 41.2%). Results demonstrate that the source of progestin does not influence the expression of estrus or the proportion of ewes pregnant following LAI. When progestin treatment protocols are used in combination with eCG, pregnancy rates can be increased. A dose of GnRH near the end of progestin treatment may decrease the estrous response, by inducing ovulation before normal expression of estrus.     

Antioxidant effects of clove bud (Syzygium aromaticum) extract used with different extenders on ram spermatozoa during cryopreservation

Clove bud (Syzygium aromaticum) extract was added at concentrations of 0, 35, 75, and 115 μg/ml to ovine semen extenders in order to investigate the antioxidant activities of clove bud extract and its effects on semen quality parameters after cryopreservation of ram spermatozoa. The basic extender was composed of Tris, egg yolk, and glycerol. Two other extenders were prepared by substitution of egg yolk with either LDL or egg yolk + SDS. The DPPH inhibition test was employed to assess the antioxidant activity of clove bud extract. Results showed that, compared to vitamin E, clove bud extract had a higher antioxidant activity. Better sperm motility and movement characteristics (P < 0.05) were observed in the semen diluted with medium containing egg yolk + SDS than in that containing egg yolk and LDL. Progressive motility and movement characteristics of the sperm were significantly improved (P < 0.05) by adding 35 and/or 75 μg/ml of clove bud extract to semen extenders. Sperm viability and plasma membrane integrity were also higher (P < 0.05) in the semen exposed to medium containing egg yolk + SDS and 75 μg of clove buds extract after cryopreservation processes. Higher levels of clove bud extract, however, had adverse effects on all the sperm quality parameters and significantly reduced (P < 0.05) the motility, movement parameters, viability, and plasma membrane integrity of ovine sperm. It was concluded that the clove bud extract had an antioxidant potential that makes it useful for addition to semen extenders and that the best results are obtained with a maximum clove bud extract of 75 μg/ml. Moreover, the combination of egg yolk and a detergent was found to improve sperm quality after the cooling and freeze–thawing processes.     

Performance of rabbits on Guinea grass and Verano stylo hays in the dry season and effect of concentrate supplementation

The feasibility of using Verano stylo (Stylosanthes hamata cv. Verano) and Guinea grass (Panicum maximum cv. Ntchisi) hays and their replacement values in concentrate diets for rabbits were determined. The intake and growth of the rabbits were monitored over a 7-week growth study following a 2-week adaptation period, while nutrient digestibility was determined over a 5-day period during the eighth week of the study. The DM intakes of the rabbits during the growth study were 53.1 g/day of the grass + concentrate (50 : 50) diet, 56.0 g/day of the all-concentrate diet and 64.8 g/day for the Verano stylo + concentrate (50 : 50) diet. The respective weight gains were 5.13, 8.44 and 8.35 g/day. Lower DM intake and consistent losses in weight of the animals were recorded on Verano stylo or Guinea grass alone. Verano stylo hay was better than Guinea grass hay. Thus, concentrate supplementation of forage diets is necessary for rabbits. Replacement of 0.50 of the concentrate with Verano stylo hay gave a similar performance to that for the all-concentrate diet. It is, therefore, possible to reduce the use of concentrates in the diets for growing rabbits in the dry season by replacing part of the diet with Verano stylo hay.     

Cryopreservation of rainbow trout Oncorhynchus mykiss spermatozoa: Effects of extender supplemented with different antioxidants on sperm motility,velocity and fertility

In present study, it was examined whether addition of different antioxidants to the cryopreservation extenders had an effect on semen post-thaw fertility and motility in rainbow trout (Oncorhynchus mykiss) and also it was investigated the sperm characteristics post-thaw sperm characteristics and fertility. The collected semen was pooled to minimize individual variation. Each pooled ejaculate was split into 12 equal aliquots and diluted with base extenders supplemented with the antioxidants, and a base extender with no additives (control). The pooled semen samples diluted at the ratio of 1:10 by the extenders were subjected to cryopreservation. Antioxidants were separately added to the extenders (one per experimental group): catalase (250 U/l), superoxide dismutase (250 U/l), peroxidase (250 U/l), oxidized glutathione (1.5 mmol/l), reduced glutathione (1.5 mmol/l), l-methionine (1.5 mmol/l), uric acid (0.25 mmol/l), l-ascorbic acid (0.5 mmol/l), α-tocopherol (2.0 mmol/l), β-carotene (0.5 mmol/l) and carnitine (0.5 mmol/l). After dilution the semen was aspirated into 0.25 ml straws, the straws were placed on the tray, frozen for 10 min, and plunged into liquid nitrogen. Our results indicated that the post-thaw motility rate increased in extenders supplemented with uric acid, l-methionine, SOD, l-carnitine, α-tocopherol and l-reduced glutathione (p < 0.05). The motility duration of frozen thawed semen increased in extenders supplemented with uric acid, l-methionine, SOD, α-tocopherol and l-reduced glutathione (p < 0.05). Fertilization rate and hatching rate of frozen-thawed semen was not affected by the tested antioxidants. Consequently, the tested antioxidants affected the motility parameters and cryopreservation extenders could be supplement with antioxidants. This study suggested usage of antioxidants in the cryopreservation of rainbow trout.     

Milk fatty acid composition of dairy cows grazing at two pasture allowances and supplemented with different levels and sources of concentrate

Milk fatty acid (FA) composition of dairy cows from two grazing studies was examined. In the first study, effects of concentrate supplementation and pasture allowance were evaluated using 20 multiparous Holstein cows in five 4 × 4 Latin squares. The four treatments resulted from the combination of two pasture allowances (i.e., low, 25 versus high, 40 kg dry matter/cow/day) and two concentrate supplementation levels (i.e., 0 versus 1 kg concentrate/4 kg milk). No interactions occurred between concentrate supplementation and pasture allowance for milk FA composition. Concentrate supplementation increased short-chain FA content, and reduced the content of long-chain FA, trans11 C18:1, and cis9, trans11 conjugated linoleic acid (CLA) (1.36 versus 1.18 g/100 g). Concentrate supplementation increased saturated FA (58.6 versus 54.0 g/100 g) and reduced unsaturated FA content (39.9 versus 43.8 g/100 g). Grazing at high pasture allowance increased short-, medium-, and long-chain FA content, without affecting cis9, trans11 CLA content. Saturated FA content was higher (57.1 versus 55.6 g/100 g), and unsaturated FA content was lower (41.3 versus 42.5 g/100 g), when cows grazed at high pasture allowance. Concentrate supplementation reduced unsaturated FA and cis9, trans11 CLA in milk of dairy cows grazing at two pasture allowances. In the second study, two experiments evaluated effects of different energy supplements in grazing dairy cows. In Experiment 1, 25 multiparous Holstein cows were assigned to a cracked corn (CC) or a steam flaked corn (SFC) supplement containing 667 g/kg of corn grain plus a pelleted protein/mineral supplement. In Experiment 2, 22 multiparous Holstein cows were assigned to a ground corn grain (GC) or a non-forage fiber (NFF) supplement. The GC supplement contained 850 g/kg of corn grain, and the NFF supplement contained 440 g/kg of non-forage fiber sources (i.e., beet pulp, soyhulls, wheat middlings) that partially replaced corn grain. Milk FA composition was not affected by corn processing or carbohydrate source. The content of short-, medium-, long-chain FA, and cis9, trans11 CLA (2.5 g/100 g in Experiment 1; 2.1 g/100 g in Experiment 2) was similar between supplements in both experiments. The type of supplement did not affect the content of saturated (62.6 g/100 g in Experiment 1; 65.4 g/100 g in Experiment 2) and unsaturated FA (37.5 g/100 g in Experiment 1; 34.6 g/100 g in Experiment 2). Supplementation with supplements differing in the rate and extent of ruminal carbohydrate digestion did not affect the milk FA composition of grazing dairy cows.     

Effect of antioxidants on microscopic semen parameters,lipid peroxidation and antioxidant activities in Angora goat semen following cryopreservation

The aim of this study was to determine the effects of the antioxidants glutamine and hyaluronan and the inclusion of different levels on microscopic semen parameters, lipid peroxidation and the antioxidant activities following the freeze–thawing of Angora goat semen. Ejaculates collected from three Angora goat bucks, were evaluated and pooled at 37 °C. The semen samples which were diluted with a Tris-based extender containing additives including glutamine (2.5; 5 mM) and hyaluronan (500; 1000 μl/ml), and an extender containing no antioxidants (control) were cooled to 5 °C and frozen in 0.25 ml French straws and stored in liquid nitrogen. Frozen straws were thawed individually (37 °C) for 20 s in a water bath for microscopic evaluation. Freezing extenders supplemented with 2.5 and 5 mM glutamine led to higher sperm motility and hypo-osmotic swelling test (HOST) values, compared to the control (P < 0.05) following the freeze–thawing process. The addition of 500 μl/ml hyaluronan resulted in a higher HOST percentage, compared to the addition of 1000 μl/ml hyaluronan and the control (P < 0.001). No significant difference was recorded in the percentage acrosome and total sperm abnormalities, following supplementation with antioxidants. The addition of antioxidants did not prevent malondialdehyde (MDA) formation, compared to the controls. Antioxidant treatment however decreased (P < 0.01) the superoxide dismutase (SOD) activity. The maintenance of catalase (CAT) activity was demonstrated to be insignificant following addition of antioxidants. Further studies are required to obtain more repeatable results regarding the characterization of the enzymatic and non-enzymatic antioxidant systems in cryopreserved goat sperm.     

Short term effects of dexamethasone on hyaluronidase activity and sperm characteristics in rams

The aim of this study was to determine the effects of dexamethasone on sperm characteristics and hyaluronidase activity of serum and semen. In this investigation, 14 healthy Akkaraman rams, at the age of 2 years and weighing between 50–60 kg, were used. The rams were randomly divided into two groups. After the last administration of dexamethasone intramuscularly at a dose of 0.25 mg/kg, semen and blood samples were taken at different times. The results showed that the serum hyaluronidase activity was increased significantly (p < 0.001) in the treatment group when compared with the control group except for the 1st hour. There was a significant difference (p < 0.001, 0.01, 0.05) in the hyaluronidase activity of semen between the treatment group and the control group. Furthermore, there was a significant difference (p < 0.01) in sperm concentration between both groups at all the times except the 96th hour. There were statistically significant (p < 0.05) differences in semen volume between the treatment and control groups. There were also significant differences (p < 0.05) in sperm motility between the treatment and control groups except for the 72 and 96th hours.These findings indicate that dexamethasone increases hyaluronidase activity of serum and semen, but it decreases sperm concentration, semen volume and sperm motility in rams. Therefore the use of these drugs in breeding rams during breeding season is not suitable.     

Objective assessment of the cryoprotective effects of dimethylformamide for freezing goat semen

The aim of this work was to assess the cryoprotective effects of dimethylformamide (DMF) for freezing goat semen, using an objective analysis by computer-assisted sperm analysis (CASA). Twenty-one ejaculates (seven per animal) were collected from three stud bucks with the aid of an artificial vagina and immediately evaluated for gross and microscopic characteristics. The semen was diluted in two steps with a Tris–egg yolk extender containing 6% glycerol or 6% DMF, frozen in 0.50-mL straws, and stored in liquid nitrogen. Samples were accessed for sperm morphology, sperm membrane structural and functional integrity, and by CASA, immediately after thawing. There were differences (P < 0.05) between glycerol and DMF with regard to subjective progressive motility (23.9 ± 2.2% vs. 16.6 ± 2.0%), objective progressive motility (3.5 ± 0.4% vs. 1.8 ± 0.3%), linearity (53.9 ± 1.6% vs. 48.1 ± 1.4%) and amplitude of lateral head (2.3 ± 0.1 vs. 2.9 ± 0.1 mm), which confirmed the efficiency of glycerol. In conclusion, dimethylformamide could be used as an alternative cryoprotectant for goat semen freezing. However it was showed that no benefits were derived by using dimethylformamide to replace glycerol at an equal 6% concentration.     

Determination of prediction equations for estimating body weight of Zulu (Nguni) sheep

Data on linear body measurements (LBM) of 403 sheep collected in three areas of KwaZulu-Natal were utilized to develop a prediction equation for live body weight of Zulu sheep. Data were collected on live weight (LW), heart girth (HG), wither height (WH) and scrotum circumference (SC) on sheep of all ages. The age of sheep was estimated by dentition. The analysis of variance showed that age and sex were important factors contributing to variation in LW of Zulu sheep. Phenotypic correlation coefficients and regression equations of LW on HG, WH and SC were computed within different age groups (milk set of teeth, one pair, two pairs and the three and four pairs of incisors). Low correlation coefficients (r = 0.21–0.48) between LW, HG and WH were found among the pregnant ewes. The relationship between LBM and LW was stronger (r = 0.66–0.86) for males than among females (r = 0.42–0.75). The cubic polynomial of HG was the best fit (R² = 0.76) for the live weight prediction of young sheep with milk set of teeth. The combination of HG and WH produced the best fit for the two tooth and above males and non-pregnant females. The LW prediction equations for pregnant females were not reliable (R² = 0.05–0.26). The SC was more precise (R² = 0.61–0.80) when estimating the live weight of young males (<15–22-month-old) than of the older rams (R² = 0.23–0.56). It was concluded that LW of Zulu sheep can be reasonably estimated using the HG and WH. A table could be constructed for the farmers to estimate the LW of their animals.     

Effects of Nigella sativa L. seed oil on abnormal semen quality in infertile men: A randomized,double-blind,placebo-controlled clinical trial

In recent years, wide utilization of herbal drugs has encouraged scientists to determine their impressive effects on health. Since Nigella sativa L. seed (N. sativa) has many uses including infertility in traditional medicine, the effects of Nigella sativa L. seed oil on abnormal semen quality in infertile men with abnormal semen quality are of interest. This study was conducted on Iranian infertile men with inclusion criteria of abnormal sperm morphology less than 30% or sperm counts below 20 × 10⁶/ml or type A and B motility less than 25% and 50% respectively. The patients in N. sativa oil group (n = 34) received 2.5 ml N. sativa oil and placebo group (n = 34) received 2.5 ml liquid paraffin two times a day orally for 2 months. At baseline and after 2 months, the sperm count, motility and morphology and semen volume, pH and round cells as primary outcomes were determined in both groups. Results showed that sperm count, motility and morphology and semen volume, pH and round cells were improved significantly in N. sativa oil treated group compared with placebo group after 2 months. It is concluded that daily intake of 5 ml N. sativa oil for two months improves abnormal semen quality in infertile men without any adverse effects.     

Reproductive responses of ram lambs under short-term exposure to endophyte-infected tall fescue seed

Our objective was to determine the influence of short-term exposure to endophyte-infected tall fescue on reproductive function of ram lambs. Rams (214 days of age) were fed a diet free of endophyte-infected fescue seed (EF; n = 8) or endophyte-infected fescue seed (EI; n = 9; 34% of diet; 4.8 μg g⁻¹ ergovaline) for 6 weeks. Feed offered to EF rams, individually fed, was reduced to the average intake of EI lambs from previous day so that intake was similar between treatments and averaged 2.4% BW (DM basis), leading to daily intake of 33.7 μg ergovaline kg⁻¹ BW for the EI fed lambs. Daily high ambient temperature for the trial ranged between 16 and 26 °C. Respiration rate and rectal temperature were measured at 14:00 daily. Blood was collected for serum concentrations of prolactin (weekly) and testosterone (twice weekly). Body weight and body condition scores (BCS; 1 = thin; 5 = fat) were determined every 14 days. Scrotal circumference, scrotal skin temperature, and semen characteristics were determined weekly. Rams were slaughtered after 6 weeks of feeding. Signs of fescue toxicosis in EI fed rams included increased rectal temperature (P < 0.001, R² = 0.11) and respiration rate (day, P < 0.001, R² = 0.25) when high ambient temperature exceeded 22 °C and reduced serum concentrations of prolactin (diet × day, P < 0.001). Body weight of EI fed rams tended to decrease after 36 days of feeding compared with EF fed rams (−3.0 kg versus 0.51 kg; P < 0.07) and BCS was similar between treatment throughout the trial. Serum concentrations of testosterone were greater in EI compared with EF fed rams (diet × day, P < 0.005, R² = 0.08). Scrotal skin temperature, scrotal circumference, semen volume, percent sperm motility, and percent abnormal sperm were similar between treatments. Spermatozoa concentration tended to be greater in EF compared with EI fed rams after 43 days of feeding (P < 0.10; R² = 0.15). Rate of forward movement of spermatozoa tended to increase at a greater rate between Days 8 and 29 in EF compared with EI fed rams (diet × day, P < 0.08). Feeding endophyte-infected fescue seed to ram lambs was associated with potential decreased fertility and increased serum concentrations of testosterone. Short term exposure of endophyte toxins to male ruminants may negatively impact reproductive responses. Feeding for longer periods may further reduce fertility and merits further research.     

Effect of a single subcutaneous injection of melatonin on estrous response and conception rate in goats

The objectives of this study were to evaluate the effect of a single subcutaneous injection of melatonin, on estrous induction and conception rate during the non-breeding season at different times of the year. In Experiment 1 the melatonin powder was dissolved in an oily vitamin A, D, E solution and injected subcutaneously randomly to goats in two dose treatment groups of 20 mg (MLT-20; n = 20) and 40 mg (MLT-40; n = 20) in January (winter). Twenty does were injected with 1 ml vitamin A and served as the control. In the MLT-20 treated goats 70% of the does were in estrus within 20.0 ± 2.0 days, whereas in the MLT-40 group 85% of the does were in estrus within 15.5 ± 2.5 days and 100% and 80% of the does, respectively, conceived on mating with the bucks. Only 10% of the untreated control does exhibited estrus, but none conceived. The breeding season was thus initiated earlier by 1–1.5 months in the treated goats. In Experiment 2, goats were treated with similar MLT-20 and MLT-40 treatments in May (spring), with 20 goats in each treatment group and 20 control goats. The proportion of goats that responded to the melatonin treatments was 80% and 90% in the MLT-20 and MLT-40 treatments, respectively, with no significant differences recorded regarding the estrous response. However, in the MLT-20 treatment group the estrous induction interval was significantly longer (P < 0.05), compared to the MLT-40 treatment. The pregnancy rates were not significantly different for the MLT-20 and MLT-40 treatments, with melatonin resulting in significantly higher pregnancy rates than in the control (88.4% versus 33.3%) and the breeding season initiated 2 months earlier. It could be concluded that a single subcutaneous injection of melatonin can initiate the breeding season (irrespective of the season of the year) earlier by 1–2 months in goats and this could be advantageous when using accelerated breeding systems.     

Combined effect of probiotics and specific immunoglobulin Y directed against Escherichia coli on growth performance,diarrhea incidence,and immune system in calves

Enterotoxigenic Escherichia coli (ETEC) K99 is one of the major pathogens associated with calf diarrhea. The induction of passive immunity in animals by immunoglobulin Y and using probiotics are inexpensive alternatives to antibiotics for the prevention and treatment of a number of bacterial infections, including diarrhea. Hence, the aim of this research was to evaluate the impact of dietary probiotics and ETEC K99-specific egg yolk antibody supplements, alone and in combination with each other, on health and growth parameters, diarrhea incidence and immune stimulation in newborn Holstein calves. One hundred and twenty neonatal calves were allocated randomly into 4 dietary groups (n = 30 per group) received colostrum/milk without any additives (control group), or supplemented with egg yolk powder contained E. coli K99-specific antibody (Ab group; 1 g/day), a commercial probiotic, Hypro-calves (Pro group; 3 g/day), and their combination (Ab + Pro group), from day (d) 1 to d28 of age. Analyses of the growth parameters, feed efficiency, fecal score, and microbiota and immune function were carried out on d0, 14, 21, and 28 of the experiment. Calves in Ab or Ab + Pro group had higher (P < 0.05) average daily gain compared to control and Pro groups during 0–14d. Feed efficiency of calves in Ab and Ab + Pro groups was significantly higher than that in control group during the period of 0–14d; however, no significant differences were observed in 0–28d period. Diarrhea prevalence and fecal score in Ab + Pro group were lower than control group (P < 0.05). Calves in Ab + Pro group had the lowest number of fecal E. coli in comparison to other groups on d28 (P < 0.05). Feeding Ab + Pro supplement increased (P < 0.05) concentrations of blood IgA and serum CD4 compared to the control group. Likewise, calves in Pro group had higher CD4 levels as compared to the control calves (P < 0.05). Serum concentration of interferon-gamma in control group was lower than other groups (P < 0.05). Overall, these data suggest that feeding a combination of probiotic and specific antibody against ETEC to neonate Holstein calves enhances feed efficiency, boosts immunity, and reduces diarrhea prevalence.     

Growth,carcass and cooked meat characteristics of lambs sired by Dorset rams heterozygous for the Callipyge gene and Suffolk and Texel rams

Dorset (D) rams heterozygous for the Callipyge gene were single—sire mated to non-carrier ewes to produce Callipyge heterozygous (CLPG, n = 49) and normal (D, n = 33) lambs. Suffolk (S) and Texel (T) rams were mated to similar ewes to produce non-carrier crossbred S (n = 55) and T (n = 52) lambs. Lambs were finished on a high-energy diet to a target live weight of 57 kg. Pre-slaughter weight was recorded for each lamb prior to its transfer and slaughter through a commercial facility. Hot carcass weight and kidney and pelvic fat (KPF) were recorded at slaughter. Chilled carcasses were measured then fabricated into trimmed retail cuts by plant personnel. Each cut was weighed, and two loin chops were collected from each carcass for later cooking. CLPG lambs had the highest dressing % (53.6 versus 49.8–50.6; P < 0.05). At the same cold carcass weight, CLPG lambs had larger longissimus muscle areas (19.5 cm² versus 14.0–15.2 cm² for the rest; P < 0.05), less KPF (0.9 kg versus 1.04–1.13 kg; P < 0.05), less carcass fat (P < 0.05 for all measures), shorter carcasses (60.7 cm versus 61.8–64.7 cm; P < 0.05), and heavier trimmed sirloins, legs, and shoulders than any other group (a11 P < 0.05). They were similar to S lambs in receiving the lowest mean USDA yield grade. CLPG carcasses had the highest proportion of carcass weight represented by trimmed cuts (70% versus 65.7–67.8% for the rest; P < 0.05), the highest proportion of trimmed cuts (62.2% versus 59.7–60.6% for the rest; P < 0.05) represented by the most valuable cuts (leg + loin + rack + sirloin), and the highest composite carcass value ($135.8 versus $125–129 for the rest; P < 0.05). CLPG lambs also produced loin chops with the highest mean Warner–Bratzler shear values (5.4 kg versus 2.8–2.9 kg for the rest; P < 0.05) and the highest % cooking loss (31% versus 29–29.6% for the rest; P < 0.05).