Effects of Tasco (a seaweed extract) and heat stress on N metabolism and meat fatty acids in wether lambs fed hays containing endophyte-infected fescue

Wether lambs (n = 27, average BW = 40 kg) were used to test response to forage treated with Tasco-Forage (an extract of the brown kelp Ascophyllum nodosum) prior to conserving, or to direct feeding of the extract (Tasco-EX). Hays made from endophyte (Neoyphodium coenophialum)-infested tall fescue (Festuca arundinacea)-based pasture received 0 or 3 kg of Tasco/ha prior to harvest. Lambs, blocked by weight, were randomly allotted to three diets: (1) control hay, (2) treated hay, and (3) #1 + Tasco-EX fed at 1% of the diet. Hays were low in CP (<7%) so all lambs were fed soybean meal (12% of the diet) in addition to trace mineralized salt. Diets were fed at 1.5% BW to prevent refusals. Total collections (7 d) were made during periods without or with applied heat stress. After each period, rumen contents were obtained to determine pH, NH₃ and VFA. Lambs were sacrificed post-trial. A subset was used to evaluate sensory traits and muscle fatty acids. Lambs were in negative N balance during the study and Tasco treatments did not affect N metabolism. Fecal N tended (P < 0.10) to increase with short duration heat stress causing a concomitant decrease (P < 0.05) in apparent N digestibility (58.6 versus 56.1%; S.E. = 0.7). Urinary N loss decreased (P < 0.001) with heat stress (8.0 versus 5.9 g/d; S.E. = 0.2), resulting in increased (P < 0.001) N retention (−2.1 versus −0.3 g/d; S.E. = 0.2). Apparent OM digestibility was not affected by heat stress but was greater (P < 0.05) for lambs fed Tasco-EX treatment than those fed treated hay. Treatment diets decreased (P < 0.05) ruminal butyrate. Heat stress increased (P < 0.05) acetate and total VFA and decreased (P < 0.01) ruminal pH. A tendency (P < 0.11) of increased 14:1ω5, decreased (P < 0.05) 18:0 and total saturated fatty acids in muscle was observed with Tasco diets. Meat sensory characteristics were not affected by treatment. Tasco may alter some aspects of rumen or lipid metabolism but has no effect on N metabolism or meat sensory characteristics of sheep fed restricted, low-quality diets.     

Effects of ileal endogenous nitrogen losses and dietary amino acid supplementation on nitrogen retention in growing pigs

The relationship between ileal endogenous nitrogen (N) losses and N retention was studied in two experiments with growing pigs of 40 to 60 kg. In Experiment 1, 13 ileal cannulated castrated males were fed diets based on maize starch, containing either soyabean meal (SBM) with a low trypsin inhibitor activity (TIA), a mixture of toasted and untoasted soyabean meal with a high TIA (mSBM), a commercial batch of peas, or rapeseed expeller cake (RC). Ileal endogenous N recovery was measured using the ¹⁵N-isotope dilution technique. Apparent ileal digestibility of crude protein (CP) for the SBM, mSBM, pea and RC diets were 82.8, 72.0, 76.7 and 68.7% (P < 0.05). True ileal CP digestibility for the diets was 96.5, 93.0, 94.0 and 87.5% (P < 0.05), and the recovery of ileal endogenous N was 3.08, 6.01, 4.55 and 5.36 g/kg DMI (P < 0.05). In Experiment 2, sixteen castrated males were used to determine N retention, using almost similar diets as in Experiment 1. The diets contained either SBM, mSBM or peas and were balanced for the contents of apparent ileal digestible (ID) CP (96 g/kg) and ID essential amino acids (EAA; at least 85% of requirement values). The fourth treatment was a diet with mSBM as protein source, but supplemented with EAA to the level of 95% of the requirement values (diet mSBMs). Apparent faecal CP digestibility for the SBM, mSBM, pea and mSBMs diets was 88.6, 87.2, 86.1 and 86.0% (P < 0.05). Urinary N excretion and N retention for these treatments were 0.39, 0.59, 0.40, 0.53 (P < 0.05) and 0.87, 0.80, 0.85, 0.84 g/kg^0.75/day (P < 0.05), respectively. Utilization of dietary ID N for N retention were 79.8, 73.3, 78.2 and 77.6% (P < 0.05), respectively. The study showed that increased ileal endogenous N losses are associated with higher losses of urinary N and with a lower N retention. Supplementation of extra essential AA to a diet causing a relatively high flow of ileal endogenous N, may compensate for the lower N utilization under these conditions, and thus limit effects on N retention.     

Effects of ensiled forage legumes on performance of store finishing lambs

Male Beulah speckled face lambs (initial live weight (LW) 28.8 ± 0.31 kg) were allocated to three dietary treatments to evaluate the performance of store lambs of a hill breed when offered ensiled lucerne (Medicago sativa), red clover (Trifolium pratense) or ryegrass. Second-cut silage bales (wilted and inoculated) were prepared from 3-year old lucerne and red clover stands and a 1-year old ryegrass sward. All the lambs were group-housed and offered ad libitum ryegrass silage during a 3-week co-variate period. This was followed by a week of dietary changeover period, after which the lambs were housed individually and offered their treatment diet ad libitum. All the lambs received a flat rate supplement of pelleted molassed sugarbeet (250 g fresh weight/day). Individual intakes were determined daily, and weekly measurements of LW and body condition score (CS) were made. Additional measurements were taken by scanning the lambs for depth of Longissimus dorsi (LD) muscle and subcutaneous fat. Over an experimental period of 7 weeks, the lambs offered red clover silage had a higher voluntary silage dry matter (DM) intake, total DM intake and metabolisable energy (ME) intake (P < 0.001) than lambs offered either lucerne or ryegrass silage. This resulted in a faster (P < 0.001) growth rate and increase (P < 0.001) in CS, with no difference between lucerne and ryegrass silages. The feed conversion efficiency (FCE) was 8.0 ± 0.61 kg feed/kg gain for lambs fed red clover silage, compared with 16.6 ± 2.82 and 10.6 ± 1.94 kg feed/kg gain for lucerne and ryegrass silage, respectively. The CP intake was higher (P < 0.001) for lambs fed the lucerne and red clover silages than for the ryegrass silage treatment. The concentration of plasma total protein (TP) was higher (P < 0.05) for lambs offered ryegrass silage versus lucerne and red clover silage. Urea concentrations were highest for lambs fed lucerne silage and lowest for those fed ryegrass silage (P < 0.05). The glucose concentration was higher (P < 0.05) for lambs offered red clover silage, whereas non-esterified fatty acids (NEFA) concentration was higher (P < 0.05) for lambs offered lucerne silage. Substituting ryegrass silage with red clover silage has the potential to improve the performance of finishing store lambs.     

Apparent protein digestibility and recovery of endogenous nitrogen at the terminal ileum of pigs fed diets containing various soyabean products, peas or rapeseed hulls

Effects of the use of three different soyabean products (soya concentrate and two different soyabean meals), peas or rapeseed hulls in the diet on the apparent ileal digestibility of CP (N × 6.25) and recovery of ileal endogenous nitrogen (N) in weanling pigs were investigated. Ileal endogenous N was measured using the ¹⁵N-isotope dilution method. Thirteen castrated male pigs (BW of 12–23 kg) were fed maize starch-based diets containing either soya concentrate (SC), purified rapeseed hulls (pRH) and SC (SRH diet), soyabean meal (SBM), a mixture of toasted and untoasted soyabean meal (mSBM) or peas. The apparent ileal digestibility (AID) of dry matter (DM) for the SC, SRH, SBM, mSBM and pea diets was 82.1, 74.3, 83.3, 80.0 and 74.9% (P < 0.05), respectively. The AID of CP for these diets was 82.4, 67.6, 81.6, 68.0 and 76.9% (P < 0.05), respectively. Similar differences in the AID for amino acids (AA) in the diets were found. The AID for CP and for the sum of AA in the pRH, as calculated by the difference between the SC and SRH diet, were 26 and 41%, respectively. For the SC, SRH, SBM, mSBM and pea diet, ileal recovery (g/kg of DM intake) for endogenous N were 2.79, 3.46, 2.73, 4.89 and 3.29 (P < 0.05), respectively, and for dietary N 1.16, 4.11, 1.64, 4.15 and 2.53 (P < 0.05), respectively. For the SC, SBM and mSBM diets, differences in AID of CP and AA were associated with differences in both the ileal recovery of endogenous N and the recovery of undigested dietary N. Differences in trypsin inhibitor activity (TIA) of the soya products were likely associated with these observations. It was also concluded that fibre (Neutral Detergent Fibre; NDF) in pea could be at least in part responsible for the relatively low AID of CP and AA and the high recovery of ileal endogenous N in the pea diet. The low AID of CP and AA of pRH was likely related to the association of protein to the fibre matrix in the fibre-rich rapeseed hulls.     

The effects of barley, unmolassed sugar-beet pulp and molasses supplements on organic matter, nitrogen and fibre digestion in the rumen of cattle given a silage diet

In a 4 × 4 Latin-square experiment with a 2 × 2 factorial arrangement of treatments, 4 cattle fitted with a rumen and duodenal cannula were given four grass-containing diets [480 g kg⁻¹ of the total dry matter (DM) intake] and barley (BU), barley + molasses (2:1) (BM), sugar-beet pulp (SU) or sugar-beet pulp + molasses (SM). Duodenal flow was estimated using Cr-mordanted straw and CoEDTA as markers, and microbial nitrogen entering the small intestine using purine bases of nucleic acids.

Molasses-containing diets had a higher (P < 0.01) organic matter (OM) digestibility. The proportion of digestible OM apparently disappearing in the rumen averaged 0.72 and was not significantly affected by the diet. When cattle received molasses, the quantity of microbial N entering the small intestine was higher (P < 0.05) and there was a trend towards a higher efficiency of microbial N synthesis (28.8 vs. 25.6 g N kg⁻¹ OM apparently digested in the rumen). When S diets were consumed, total non-ammonia N flow at the duodenum exceeded N intake by 7.0 g day⁻¹ and when B diets were consumed, it was 0.7 g day⁻¹ less than N intake. Feed N degradability in the rumen and apparent N digestibility of S diets were lower (P < 0.05; P < 0.001) than those of B diets.

Rumen (P < 0.05) and total (P < 0.001) digestibility of neutral detergent fibre (NDF) and acid detergent fibre (ADF) was higher when S diets were given. The proportion of digestible fibre disappearing in the rumen was not affected by the diet. The rate and extent of silage and hay DM degradation were not significantly affected by the diet. However, dietary inclusion of molasses decreased (P < 0.05) the lag time of both hay and silage DM degradation.

The rumen dilution rate of liquid averaged 0.097 and that of particles, 0.049; neither was significantly different for either B and S diets or U and M diets. Duodenal liquid flow was higher (P < 0.05) for M diets.

Average rumen pH was not affected by the diet, but the molasses diets increased (P < 0.05) the range in rumen pH. The BM diet was associated with higher (P < 0.01) rumen ammonia concentration than the other diets. Low rumen ammonia concentrations (< 2 mM) were observed for long periods between feeds. The molar proportion of butyrate was higher on B diets and there was a trend towards a higher proportion of acetate and propionate on S diets. Molasses tended to increase the molar proportion of propionate and butyrate.     

Influence of stock density and rate and temporal patterns of forage allocation on the diet mixing behavior of sheep grazing sagebrush steppe

An animal's ability to select a diet depends on forage availability, the density of herbivores, and the allocation of forage resources. We hypothesized that the temporal and spatial availability of forages in sagebrush steppe vegetation both influence food selection and may encourage lambs to learn to use sagebrush, a shrub that contains high levels of terpenes that limit food intake. We conducted a field study with three treatments of 20 lambs each. Forage resources were manipulated by restricting grazing areas. Lambs in treatment H grazed at a high stock density, whereas lambs in treatment L grazed at a low stock density; both groups were moved to fresh pasture daily. Lambs in treatment H3 had three times the area of treatment H, but they were moved every 3 days, making the total area grazed by H and H3 equal, but with a different temporal allocation of forage. Scan sampling was used to record the incidence of consumption among sagebrush and understory herbs. During 24 days of conditioning, stock density and temporal patterns of forage allocation both influenced the behavior of lambs. Lambs in H spent more time foraging on sagebrush (25%) than lambs in H3 (16%), and lambs in both H and H3 spent more time foraging on sagebrush than lambs in L (1%) (P < 0.05). For lambs in H3, foraging on sagebrush was cyclic and depended on the daily availability of herbs. Use of sagebrush, expressed as a percentage of total foraging time, was <1% for day 1, 13% for day 2, and 37% for day 3 (P < 0.0001). Importantly, use of sagebrush by H3 and H increased steadily as the trial progressed, whereas use of sagebrush by L was consistently low (P < 0.05). Following conditioning, when lambs were tested at low stock densities during preference test 1, use of sagebrush did not differ by groups, but at higher stock densities in preference test 2, their use of sagebrush varied by treatments: H > H3 > L (P < 0.005). Thus, the availability of alternative foods, manipulated through animal density and the temporal allocation of those resources, both affected how readily lambs learned to use sagebrush.     

Surgical castration of pigs affects the behavioural response to a low-dose lipopolysaccharide (LPS) challenge after weaning

The objective of the present study was to evaluate the effect of an acute stressor in the early postnatal life of pigs, surgical castration, on post-weaning behaviour, and on the behavioural, endocrine and immune responses elicited by a low-dose lipopolysaccharide (LPS) challenge after weaning. At 5-days-of-age, 64 male piglets were randomly assigned to undergo surgical castration or were left untreated (treatment). Pigs were weaned at 28 days-of-age. Behaviour post-weaning and mixing was assessed during a 1-h period, during which agonistic interactions were recorded. One day post-weaning, pigs were injected intraperitoneally with a single dose of 0 or 5 μg/kg of BW of LPS from Escherichia coli (challenge). Sickness behaviour was studied by scan sampling every 5 min for 45 min at 0, 1, 2, 3, 4, 6 and 8 h after the challenge. Blood samples were taken at 0, 2, 12 or 24 h after injection and were analysed for plasma concentrations of tumor necrosis factor-alpha (TNF-), interleukin-1beta (IL-1β), C-reactive protein (CRP), serum amyloid A (SAA) and cortisol. Results showed that non-castrated pigs were more aggressive than castrated pigs immediately after weaning (P < 0.05). Administration of LPS provoked behaviours characteristic of sickness including a reduction in general activity, as well as decreased eating and exploratory behaviours (P < 0.05). These altered behaviours occurred predominantly 3-h post injection (P < 0.05). Significant treatment by challenge interactions showed that castration reduced the occurrence of sickness behaviours induced by LPS, such as depressed general activity (P < 0.01), anorexia (P < 0.01) and reduced exploratory behaviours (P < 0.05). LPS administration increased TNF- levels (P < 0.05), with peak concentrations 2 h after injection (P < 0.01). CRP levels of LPS-treated pigs were higher than saline-treated animals at 12 h (P < 0.05). LPS administration tended to increase plasma SAA levels (P < 0.1), but did not increase cortisol levels (P > 0.1). However, castration did not affect the response of pro-inflammatory cytokines, acute phase proteins and cortisol to the challenge. These results show that surgical castration reduces aggressiveness at weaning and affects specific sickness behaviours but not the endocrine and immune responses elicited by low-dose endotoxin challenge in weaned pigs.     

Control of postpartum anestrous with an intra-vaginal progesterone device plus eCG or calf removal for 120 h in suckled crossbred cows managed in a pasture-based system

To control postpartum anestrus and reduce calving to conception interval, 167 crossbred non-pregnant cows that were 90–130 days postpartum were allotted randomly to one of the following treatments: PH (n = 59), intra-vaginal sponge with 250 mg of medroxyprogesterone acetate (MAP) for 7 days plus 50 mg of MAP and 5 mg 17-β estradiol (17β-E) in the first day of treatment (day −8), 500 UI eCG (day −3) and 1.5 mg 17β-E in 24 h after sponge removal (day 0); CR (n = 57), temporary calf removal for 120 h; CG (n = 51), control group without treatment. Estrus rate differed among treatments (P < 0.01) being greater in PH (78.2%), followed by CR (52.0%) and CG (22.9%). A greater proportion of cows in the PH (80.0%) and CR (54%) groups had ovulations when compared to CG (35.4%). Intervals to first estrus were 13.5 ± 6.3 days, 26.1 ± 6.4 days and 52.5 ± 7.5 days for the PH, CR and CG groups, respectively. First insemination conception was similar in the three groups. Postpartum intervals to first breeding (PFS) and to conception (PCI) were longer in CG than PH and CR groups (P < 0.05; P < 0.01). The PH and CR groups had a similar PFS but PCI was different (P < 0.02). Accumulated pregnancy rate at 30 and 60 but not at 90 days were different (30 days: P < 0.09; P < 0.01; P < 0.09; 60 days: P < 0.06; P < 0.01; P < 0.03) among treatments. After 90 days post-treatment, 9%, 18% and 33% of cows from the PH, CR and CG groups had not conceived. Similarly, 5.4%, 6.0% and 12.5% of cows from the PH, CR and CG groups, respectively, were culled from the herd because of lack of pregnancy after 180 days post treatment. In the group of cows evaluated by ultrasonography, only those cows having larger ovaries and dominant follicles had ovulations. It was concluded that the hormonal treatment was more efficient in inducing a fertile estrus and reducing calving to conception interval followed by the calf removal for 120 h. Each method can be considered as an important tool to reduce the postpartum anestrous period in dual purpose herds when AI is conduct in the tropics.     

Effect of feeding tree leaves as supplements on the nutrient digestion and rumen fermentation pattern in sheep grazing on semi-arid range of India – I

A study was carried out to determine the effect of feeding different tree leaves as supplements on nutrient digestion, rumen fermentation and blood parameters of sheep grazing on a semi-arid rangeland. Thirty adult Malpura rams of uniform body weight (39.0 ± 0.75) were divided into five groups of six each. They were grazed as a single flock from 08.00 to 17.00 h on a semi-arid rangeland. After the end of the grazing period, the first group (G1), which was not provided with any supplementation, served as the control. The second group (G2) was supplemented with 200 g of a concentrate mixture per head per day, whereas the third, fourth and fifth groups (G3–G5) were provided with approximately 200 g DM d⁻¹ of freshly cut foliage from Prosopis cineraria, Acacia nilotica and Albezia lebbek. The foliage from P. cineraria contained 133.4 g kg⁻¹ DM condensed tannin (CT) with protein precipitating capacity (PPC) of 66 g kg⁻¹ DM, whereas A. nilotica contained 18.9 g kg⁻¹ DM hydrolysable tannin (HT) with PPC of 11.5 g kg⁻¹ DM. However, A. lebbek did not contain any tannin. The protein contents were 119, 139 and 194 g kg⁻¹ DM, respectively. The DMI (g d⁻¹) was 688, 916, 1024, 1003, 999 in G1, G2, G3, G4 and G5, respectively. Digestible crude protein (DCP) and metabolizable energy (ME) intakes in supplemented groups G2–G5 were higher (P < 0.05) than in the control (G1). Supplementation improved the DM digestibility in all groups, whereas CP digestibility was lower (P < 0.05) in G3 compared to G2, G4 and G5. Rumen fermentation study conducted 6 h after supplementation revealed that total N, ammonia N, and total VFA levels were lower (P < 0.05) in G3 compared to the other supplemented groups. Although the haemoglobin (Hb) levels were similar among groups, blood urea N (BUN) was lowest in G3 compared to the other groups. The initial body weights were similar among groups (mean 39 kg). After 60 days of experimental feeding, all groups maintained their body weight, except the control group (G1), which lost body weight. It was observed, that supplementation with tree leaves containing CT like P. cineraria helps in better rumen fermentation pattern by preventing excessive loss of nitrogen. It was concluded that maximum nutritional benefits of tree leaves could be harvested, if used as supplement rather than as a sole feed.     

Relationship between male-male and male-female sexual behavior in 5-6-month-old male lambs

To characterize male–male sexual behavior during lamb development, to relate it with lamb body and testicular growth, and with sexual behavior toward estrual ewes, 40 Milchschaf male lambs, weaned at 45 days of age, were kept with ewes that were nursing younger lambs. Experimental lambs were weighed and scrotal circumference was measured every 2 weeks. Male–male sexual behavior was observed during 1–2 h every 2 weeks after birth until 7 months of age. Observations were recorded more intensively (3–4 h on five different days) for 2 weeks (5–6 months of age) as male–male sexual behavior increased during that period. Both mounting and mounted lambs were identified. An individual mounting index (MI) was calculated. To study male–female sexual behavior, lambs were individually located with two estrual ewes, and during 5 min the number of ano-genital sniffing, lateral approaches, mounts, and mounts with ejaculation were recorded. From those data, a libido index was also calculated. Male–male mounts (n = 308) were observed. Courtship behavior was displayed in 25% of interactions; mounts were accepted in 72.1% of attempted mounts. Mounts without previous courtship were accepted more frequently than mounts with previous courtship (P = 0.002). Lamb weight and scrotal circumference were not different according to MI groups. Lambs that mounted more times estrual ewes (first tertile) had greater (P = 0.04) MI (0.61 ± 0.10) than lambs with medium (0.27 ± 0.09) and less (0.30 ± 0.10) MI. The regression between MI and heterosexual libido index was r = 0.33 (P < 0.05). In summary, intensive male–male sexual activity during a short period of male lamb development was observed. There was a positive relationship between sexual behavior of male lambs towards other male lambs and towards estrual ewes.     

Effect of strategic supplementation with multi-nutrient urea molasses blocks on body weight and body condition score of Lohi sheep owned by tenants of Pakistan

The effect of strategic supplementation with multi-nutrient urea molasses blocks (MNUMB) on BW and body condition score (BCS) in Lohi ewes (treated, n = 514) during late gestation and lactation was compared with those (control, n = 391) grazing on only post-harvest crop residues and road side in the irrigated district of Okara in central Punjab (Pakistan). Analysis of variance revealed highly significant (P < 0.01) differences in body weight (BW) and body condition score (BCS) of ewes of various ages with different reproductive status and seasons under both flocks. Analysis of variance also revealed a significant interaction (P < 0.05) between reproductive status and seasons in favor of BCS. Ewes aged 48 months in average constituted the highest (34.5% and 35.6%), whereas those aged 60 months had the smallest (10% and 4%) proportion in the control as well as in the treated flock. Mean BW and BCS in ewes of control flock was 33.5 and 2.08 kg, and lower (P < 0.05) than 35.0 and 2.31 in ewes in the treated flock, respectively. Ewes aging 12, 24 and 36 months treated with strategic supplementation of MNUMBs were not only heavier (P < 0.01) but also had highest BCS of 2.34. Lactating ewes constituted highest proportion (39%, 51%) followed by pregnant (35%, 32%) ewes in both flocks, respectively. Proportion of dry (16%) and freshly conceived (9.5%) ewes tended to be higher in the control than in the treated flock. BW was 8–11% higher (P < 0.01) in pregnant than in lactating or dry ewes in both flocks with similar BCS. Seasons of autumn and summer were found to affect BW more (P < 0.01) than BCS. Pregnant ewes in treated flocks had gained highest BW, 10–12% higher than ewes under control (P < 0.01) or than non-pregnant ewes (P < 0.05) but lost at a rate of 5–6% at lambing. BW in lactating ewes in treated flock was higher (P < 0.01) than ewes in control. Lambs suckling ewes with strategic supplementation of MNUMBs grew at a faster rate (122 g/day) with 10–15% higher survival rate than those (97 g/day) in the control flock during lactation of 16 weeks but non-significantly. Based on this improvement it can be concluded that supplementation with appropriate sources of energy and N exerts desirable effects on the traits of economic importance in sheep.     

The relationship between heart rate and energy expenditure in Alpine, Angora, Boer and Spanish goat wethers consuming different quality diets at level of intake near maintenance or fasting

Six Alpine (AL; 38.4 ± 3.0 kg), Angora (AN; 23.1 ± 2.7 kg), Boer (BO; 40.8 ± 4.5 kg) and Spanish (SP; 33.6 ± 2.2 kg) wethers (1.5 yr of age) were used to determine the effects of time of the day and potential interactions between time, genotype and diet quality on energy expenditure (EE), heart rate (HR) and EE:HR when fed near maintenance and fasting. The experiment consisted of four simultaneous crossovers, with 21 d for adaptation before measures. Diets were 60% concentrate (CON: 15% CP) and ground alfalfa hay (FOR: 23% CP), offered in two meals at 8:00 and 16:00 h. Energy expenditure was determined from O₂ consumption and production of CO₂ and CH₄ over 2-day periods in fed and fasting states (total 4-day fasting period). Fasting EE was higher during the day than night, with values generally highest at 16:00–17:00 h. Animal within breed affected EE, HR and EE:HR (P < 0.05). The diurnal pattern in EE varied with diet (P < 0.05), although total daily EE was not different between diets. Before the morning meal, there were a number of hours during which EE was greater for CON than for FOR. However, at both meals the rise in EE was considerably greater for FOR versus CON, lasting for 3–4 h. The same general pattern in HR was observed, although the period of time when there was a dietary difference after the afternoon meal was shorter. For both fed and fasted goats, EE:HR differed among hours of the day (P < 0.05). EE:HR tended (P < 0.09) to differ between diets (5.99 and 6.21 for CON and FOR, respectively) and to be affected (P < 0.09) by an interaction between breed and diet (AL: 5.84 and 6.38; AN: 5.91 and 5.73; BO: 6.05 and 6.58; and SP: 6.17 and 6.15 kJ/(kg BW^0.75 × day):heart beats/min) for CON and FOR, respectively. In conclusion, for use of HR to predict EE by goats, it appears desirable to determine the ratio of EE:HR with a diet similar to that consumed during prediction and over an extended period of time.     

Evaluation of Florina (Pelagonia) sheep breed for growth and carcass traits

Two experiments were conducted to evaluate the performance of growing Florina (Pelagonia) lambs fed a high concentrate diet, as well as the effect of slaughter weight on carcass characteristics. The assessment of the growth used 12 male and 12 female individually penned weaned lambs until they reached 60% of their mature body weight (BW), while assessment of the effect of slaughter weight at weaning (42 days of age), and at 30%, 45% and 60% of the mature BW, on carcass characteristics used 40 male and 40 female weaned lambs. In experiment 1, results showed that Florina lambs have good growth. Male lambs grew faster (P < 0.001) than female lambs, resulting in a lower (P < 0.001) feed conversion ratio (FCR) for males. Rate of gain, feed consumption and FCR increased (P < 0.001) as the experiment progressed. In experiment 2, results showed that degree of maturity affected (P < 0.001) fasted body weight and carcass weight, as well as all carcass characteristics and commercial cuts, except the steaks cut which did not differ. Florina lambs can be slaughtered in heavier carcass weights, heavier than the 15 kg as the present practice. The heavier carcasses can appeal to wider range of consumers due to the excellent muscle development and the reduced visible fat cover. Florina sheep raised for heavy carcass meat production may be more economically beneficial for the breeders and the increased meat produced locally can help reduce need for importing meat from abroad.     

Examination of cyclic changes in bovine luteal echotexture using computer-assisted statistical pattern recognition techniques

B-mode sonography is a well-established diagnostic tool for determination of cycle stage in gynaecology. The aim of this study was to determine whether computer-assisted texture analysis of B- mode sonographic images of bovine luteal glands provides further information about the animal's plasma progesterone concentration and cycle stage. Four Simmenthal cows were examined during two consecutive estrous cycles with an ultrasound device equipped with a 7.5 MHz microconvex probe. During each examination three B-mode images of the corpus luteum (CL) were digitized and analyzed off-line using a computer-assisted texture analysis program. Size, echogeneity, and echotexture of the CL were characterized by the following texture parameters: area of cross-sectional planes of the CL (A), mean gray level (MGL), correlation (CORR), run percentage (RPERC), and long-run emphasis (LREM). Plasma progesterone levels (P4) were also determined. All parameters showed characteristic changes during the estrous cycle (P < 0.05). Variance component estimates for the effect of Day of estrous cycle on A, MGL, CORR, RPERC, and LREM were 56.6%, 64.6%, 77.6%, 89.9%, and 86.0%, respectively, and 20.6%, 24.5%, 7.2%, 0.0%, and 14.0% for the influence of the individual cow. The factor estrous cycle within cows was responsible for 22.8%, 10.9%, 15.2%, 10.1%, and 0.0% of the variability of A, MGL, CORR, RPERC and LREM values, respectively. Cyclic changes were similar in A and P4. In contrast to P4, which decreased already between Days –5 and –3 (Day 0 = ovulation), A stayed at constant high values until Day –3. Mean MGL values were higher (P < 0.05) on Days 7, 9, and 13 compared to Days 3 and –3. Mean CORR values were constantly high (P > 0.05) during the first days after ovulation and decreased continuously (P < 0.05) between Days 5 and 13. Thereafter, mean CORR values remained low (P < 0.05) until the next ovulation, except on Day –3 (P < 0.05). Mean RPERC rose between Days 1 and 9 from low to high values (P < 0.0001) remained at these high values (P > 0.05) between Days 9 and 15, and decreased (P < 0.05) afterwards to baseline values on Day –1. Mean LREM inclined steeply (P < 0.0001) from minimum to maximum between Days 1 and 5. From Days 7 to –3, mean LREM remained (P > 0.05) at a constant level close below the maximum value, and decreased to baseline values on Day –1. The results of this study show that statistical pattern recognition techniques provide new information about the luteal glands, thus facilitating a more accurate differentiation between different cycle stages in cows.     

Effect of monensin, fish oil or their combination on in vitro fermentation and conjugated linoleic acid (CLA) production by ruminal bacteria

An in vitro study was conducted to examine the effect of adding monensin, fish oil, or their combination on rumen fermentation and conjugated linoleic acid (CLA) production by mixed ruminal bacteria when incubated with safflower oil. Concentrate (1 g/100 ml) with safflower oil (0.2 g/100 ml) was added to a mixed solution (600 ml) of strained rumen fluid and buffer (control). Monensin (10 ppm), fish oil (0.02 g/100 ml), or monensin plus fish oil was also added into control mixture. All the culture solutions prepared were incubated anaerobically at 39 °C for 12 h. A higher pH and ammonia concentration were observed from the culture solution containing monensin at 12 h of incubation than those from the control or the culture containing fish oil. Monensin increased (P < 0.007) the C₃ content over all the collection times of culture solution while reducing the C₄ content at 6 h (P < 0.018) and 12 h (P < 0.001) of incubations. Supplementation of monensin, fish oil or their combination changed the content of C₁₈-fatty acids of ruminal culture. Monensin alone reduced (P < 0.021) the content of cis-9, trans-11 CLA compared to fish oil at all sampling times, but increased (P < 0.041) the trans-10, cis-12 CLA production compared to fish oil addition and the control which were similar at incubation for 12 h. The combination of monensin and fish oil increased the content of cis-9, trans-11 CLA (P < 0.023) and transvaccenic acid (TVA, P < 0.018) significantly compared to the control or monensin alone at incubation for 12 h.     

Effects of Acacia nilotica, A. polyacantha and Leucaena leucocephala leaf meal supplementation on performance of Small East African goats fed native pasture hay basal forages

Optimal utilisation of tannin-rich browse tree fodders including Acacia spp. foliages as crude protein (CP) supplements to ruminants in the tropics is limited by less available information on their feed nutritive potential. Two studies were conducted to: (1) determine rate and extent of ruminal dry matter (DM) degradability (DMD) and (2) investigate effect of sun-dried Acacia nilotica (NLM), A. polyacantha (PLM) and Leucaena leucocephala leaf meal (LLM) supplementation on growth performance of 20 growing (7–9 months old) Small East African male goats (14.6 ± 0.68 kg) fed on native pasture hay (NPH) basal diet for 84 days in a completely randomised design experiment in north-western Tanzania. The goats were randomised into four treatment groups consisting of five animals each. Three supplement diets: 115.3 g NLM (T₂), 125.9 g PLM (T₃) and 124.1 g LLM (T₄), which was used as a positive control, were supplemented at 20% of the expected DM intake (DMI; i.e., 3% body weight) to the three animal groups fed on NPH (basal diet) compared to the animals in a control group that were fed on NPH without browse supplementation (T₁).

NPH had significantly the lowest (P < 0.05) CP of 45.5 g kg⁻¹ DM compared to NLM, PLM and LLM (159, 195 and 187 g kg⁻¹ DM, respectively). NPH had higher (P < 0.05) fibre fractions; lower ruminal DM degradability characteristics and ME than NLM, PLM and LLM. Supplementation of the animals with browse resulted to (P < 0.05) higher average daily weight gains (ADG) of 157.1 g day⁻¹ in T₄ than the animals fed on T₂ (114.3 g day⁻¹) and T₃ (42.9 g day⁻¹), and even to those fed on T₁ (control), which lost weight (−71.4 g day⁻¹). Improved weight gains were mainly due to corrected feed nitrogen (N) or CP due to supplementation of the animals with browse fodder. Too low CP of the NPH would not meet the normal requirements of CP (80 g CP kg⁻¹ DM) for optimal rumen microbial function in ruminants. Higher ADG due to LLM (T₄) and NLM (T₂) supplementation suggest optimised weight gains due to browse supplementation (20% of expected DMI); while lower weight gains from supplementation with PLM (T₃) indicate the possible utilisation of A. polyacantha leaves to overcome weight losses especially during dry seasons.     

Parity of female goats does not influence their estrous and ovulatory responses to the male effect

The objective of the present study was to determine whether parity is a factor that influences the estrous and ovulatory responses of female goats when they are stimulated by males that show increased sexual activity. To stimulate sexual activity, four adult male goats were subjected to photoperiodic treatment for 2.5 months comprising long days, with the treatment commencing on 1 November. On 14 April at 1900 h, a group of multiparous females (n = 21) and a group of 16 months-old nulliparous females (n = 19) were exposed to four bucks (two per group) for 15 days. Throughout the study period, the estrous behavior of these female goats was detected twice on a daily basis. Ovulations of the female goats were determined by ecography on days 7 and 18 after exposure to males. The sexual behavior of males was recorded twice every day from 0800 to 0900 h and from 1730 to 1830 h during the first 4 days after introduction in the pen of females. The total cumulative proportion of multiparous females that had ovulations (100%) and displayed estrous behavior (100%) during the 15 days of exposure to males did not differ (P > 0.05) from that of nulliparous females (100% and 95%, respectively). The interval between introduction of males and onset of estrous behavior did not differ (P > 0.05) between multiparous (1.9 ± 0.1 days) and nulliparous (1.7 ± 0.2 days) females. The proportion of females displaying a short estrous cycle was greater (P < 0.05) in multiparous (13/21, 62%) than in nulliparous (5/19, 26%) females. Duration of these shorter than typical estrous cycles did not differ (P > 0.05) between groups (multiparous: 5.2 ± 0.3 days, nulliparous: 4.5 ± 0.1 days). The number of anogenital sniffings was greater (P < 0.001) in males exposed to nulliparous than in those exposed to multiparous females. In contrast, the number of mounting attempts was greater (P < 0.01) in males that were introduced to multiparous than in those that were introduced to nulliparous does. The number of flehmen, nudging, self-marking with urine, and mounts was not different (P > 0.05) between males that were in contact with multiparous and nulliparous females. These results indicate that regardless of parity, female goats respond to male introduction if they are stimulated by males that were previously exposed to artificial long days to increase their sexual behavior.     

Serum concentrations of Cu, Zn, Fe, Mo and Co in newborn lambs following systemic administration of Vitamin E and selenium to the pregnant ewes

This study was conducted to determine the effects of systemic administration of Vitamin E and selenium to pregnant ewes at the late stage of gestation on serum concentrations of Cu, Zn, Fe, Mo and Co in their offspring's. Pregnant Lori–Bakhtiari ewes (n = 14) were randomly assigned to receive Vitamin E and selenium (treatment group; n = 7) or distilled water (control group; n = 7), once 3 weeks and again 1 week before parturition. Blood samples were taken from jugular vein of lambs at parturition and once a week during the 4 week of age. Serum concentration of Fe, Cu, Zn, Mo and Co was determined by atomic absorption spectrophotometery.

At parturition, serum concentration of Cu, Zn, Mo and Co were identical in lambs of both groups, while the serum concentration of Fe (mean ± S.E.) was significantly higher in lambs of control (210.83 ± 9.05 μg/dl) than treatment group (140.71 ± 17.8 μg/dl).

From parturition to the forth weeks of age the serum concentrations of Fe and Cu were increased (P < 0.05) in lambs of treated group which was concomitant with a reduction in Zn concentration.

In conclusion, increase in serum concentrations of Cu and Fe during the first 4 weeks of age in lambs of ewes given vitamin E and selenium compound, could disturb the Zn:Cu and Zn:Fe ratios which in turn lead to zinc deficiency.     

The utilization of canola and its constituents by lactating dairy cows

Three feeding trials and one nylon bag trial were conducted to determine the effect of supplementing a barley-based control diet with 3.5% canola oil (CO), 22% presscake (CPC) or 9% whole seed (WCS) on feed intake, digestibility, milk yield and composition of lactating dairy cows. Ruminal utilization of canola meal (CM), CPC and WCS was also determined. Increasing the level of fat in the diet had no significant effect on intake of concentrate or digestible energy, or on total tract digestibility of dry matter (DM), crude protein (CP) and acid detergent fibre. Addition of canola in the form of CPC and WCS gave greater energy and ether extract digestibility than C and CO (P < 0.05). Diet had no significant effect on milk production, yield of milk CP, milk lactose + ash, gross energetic efficiency of milk production, milk urea or minerals. Milk fat and 4% fat corrected milk (FCM) yield were similar with the C and CPC diets, and with the CO and WCS diets. But the CO and WCS diets gave less milk fat and FCM than the C diet (P < 0.05). Milk crude protein was higher (P < 0.05) on the WCS diet than on the C, CO and CPC diets, which were similar. Diets WCS, C and CO promoted similar levels of blood urea (BU) but BU levels with CPC and CO were lower than with the C diet (P < 0.05). Ruminal DM and CP disappearance of CM was lower than for WCS and CPC at all incubation times (P < 0.05).     

Prolactin regulation of testicular development and sexual behavior in yearling Suffolk rams

The aim of this study was to determine how the yearly prolactin rhythm might affect the sexual development of Suffolk rams (latitude 50°N). Five rams were injected daily with bromocriptine (35–45 μg kg⁻¹ body weight) for 1 year, beginning in January (early winter) when rams were 11 months of age. Five control rams each received daily injections of the vehicle. In the controls, blood prolactin was <7.5 ng ml⁻¹ in winter, increased (P < 0.01) to a peak of 172.6 ± 11.9 ng ml⁻¹ after the spring equinox, and remained high during summer before declining (P < 0.01) to 29.6 ± 6.6 ng ml⁻¹ at the autumn equinox. Suppression of the seasonal rise in prolactin secretion with bromocriptine slowed testicular growth (50%; P < 0.05) in April and May (spring), thus delaying the time of peak testis size and sperm production by 1 month. Serum testosterone level was lower (50%; P < 0.01) in the treated rams than the controls in June and July (early summer), due mainly to reduced stimulation of the testes by smaller (P < 0.01) LH pulse releases or to smaller (P < 0.01) testosterone responses to LH releases, respectively. Suppression of prolactin also seemed to disrupt the central activation of gonadotropin secretion in that seasonal increases in serum FSH level and LH pulse amplitude and frequency were unusually slow (P < 0.05). These anomalies did not affect testis growth, which was normal from June until development was complete. Rams were sexually inexperienced when libido was first tested in July (non-breeding season). Both groups were equally capable of learning and expressing sexual behavior (i.e. normal mounting and ejaculation frequencies), which was more intense in September (breeding season; P < 0.05). Results support the hypothesis (based on the location of prolactin receptors) that the spring increase in prolactin secretion could target both the testes and the hypothalamic–pituitary system and be involved in the seasonal regulation of sexual function in the young adult Suffolk ram.