Blood and Colostrum/Milk Serum γ‐Glutamyltransferase Activity as a Predictor of Passive Transfer Status in Lambs

The importance of blood and colostrum/milk serum γ‐glutamyl transferase (γ‐GT) enzyme activity was evaluated to assess passive transfer status in healthy lambs. Thirty Akkaraman sheep (3–6 years old) were used which had normal pregnancy period and the same conditions, and the age of the lambs ranged between 0 and 15 days. Blood and colostrum/milk samples were collected from sheep and lambs after birth, before suckling (0) and after on 1st, 3rd, 7th and 15th days. Serum immunoglobulin G (IgG) concentration was determined by the use of Single Radial Immunodiffusion method. Serum γ‐GT activity was measured, using a commercially available kit in blood and colostrum/milk samples. Correlations were carried out between immunoglobulin and γ‐GT levels. Regression models (simple and multiple) were calculated with significant data. Linear correlation was determined between colostrum/milk γ‐GT activity and IgG concentrations and between serum γ‐GT activity and IgG concentrations in lambs on the 0 day. (r: 0.607, P: 0.001), 1st (r: 0.768, P: 0.001) and the 3rd (r: 0.603, P: 0.001) days and on the 1st (r: 0.637, P: 0.001) and 3rd (r: 0.478, P: 0.012) days in the experiment, respectively. Multivariate regression models were developed to estimate sample IgG concentration. Serum and colostrum/milk IgG concentration could be predicted using the formula: lamb serum IgG = 825 + 0.688 (lamb γ‐GT) + 52 (days); colostrum/milk IgG = 832 + 0.505 (colostrum/milk γ‐GT) ? 167 (days). The regression models were moderately accurate in predicting serum IgG concentration (R² = 0.51) and colostrum/milk IgG concentration (R² = 0.55). Test sensitivity and positive predictive values for serum γ‐GT enzyme activity were found to be 96 and 100% and for colostrum/milk γ‐GT enzyme activity were found to be 100 and 68% to prediction IgG concentration. Serum and colostrum/milk γ‐GT activity can be used to assess passive transfer status of lambs. Along with this, regression models used to calculate serum and colostrum/milk γ‐GT activities found to be useful to estimate sample IgG concentration. The use of serum and colostrum/milk γ‐GT enzyme activity was found useful especially after birth on the 0, 1st and 3rd days.     

The effect of high calcium intake by pregnant Awassi ewes at late gestation on minerals status and performance of ewes and newborn lambs

Calcium (Ca) requirement increase rapidly by pregnant ewes at late gestation as a result of high fetal growth. Furthermore, Ca deficiency results in poor growth and bone development in growing newborn lambs. The aim of this study was to evaluate the effect of calcium supplementation (Calcium carbonate–CC) and vitamin AD₃E injection (75,000 IU/shot) to pregnant Awassi ewes at late gestation (− 45 days prepartum) on their mineral levels and performance of their newborn lambs. Forty pregnant Awassi ewes at late gestation (65 ± 6.1 kg) were selected before parturition (− 45 days; using hormonal sponges for estrus synchronization) and randomly divided to 4 dietary treatments. The treatments were: group 1 Control (1.4% CC); group 2 (2.4% CC); group 3 (1.4% CC + 2 shots vitamin AD3E at − 45 and − 21 days prepartum); group 4 (2.4% CC + 2 shots vitamin AD3E at − 45 and − 21 days prepartum). Blood samples were collected from ewes (− 45, 0 days prepartum: 30 and 60 days postpartum) and lambs (0, 30 and 60 days old). Average milk yield and samples were collected. Body weights of lambs were taken at birth, 30 and 60 days old. Blood serum and milk samples were prepared and analyzed by AAS for Ca, Mg, Co, Mn and Cu concentrations.Calcium concentrations in bloods serum of ewes, 0 and 60 days postpartum, and lambs at weaning (60 days old) from group 4 were significantly (P < 0.05) higher compared to other groups. No significant effect (P > 0.05) of treatment on Co, Mg and Cu in blood serum of ewes and lambs except for Cu concentration in ewes. Moreover, a significant increase (P < 0.01) in milk inorganic% (30 and 60 days samples) in ewes from group 2 when compared with other groups. The average milk yield (AMY) of ewes from group 2 and 4 at late stage of lactation (45–60 days) were significantly higher (P < 0.05) compared to groups 1 and 3. In addition, Ca% in colostrums samples from ewes in groups 2 and 4 were significantly higher (P < 0.01). The average daily gain (ADG) and total body gain for lambs up to weaning (60 days old) were significantly higher (P < 0.05) in groups 1 and 2 compared with the other groups.In conclusion, increasing level of Ca intake in feed of Awassi ewes at late gestation, with or without vitamin AD₃E injections, improve the calcium concentration in colostrums and blood serum of ewes and their lambs without negative effect in their health and performance.     

Effect of aflatoxin on performance, hematology, and clinical immunology in lambs.

Twenty-four female lambs were intoxicated with a diet contaminated with 2 ppm aflatoxin for a period of 37 d. Twelve lambs were maintained as the control group. After this period, the lambs were left for 35 d without aflatoxin in their feed. Performance, hematology and clinical immunology were examined in the intoxicated lambs. A non-significant decrease in body weight was observed in the intoxicated lambs during the intoxication period, whereas a significant decrease (P<0.001) in average daily gain was noted on the last day of intoxication and during the clearance period. No significant differences were observed in erythrocyte count, white blood cell count or differential leukocyte count between the groups. Bacteriostatic activity of the serum was lower in the intoxicated lambs, however, there was no effect on serum opsonic activity. Phagocytosis by the neutrophils was higher during the intoxication period and the levels of IgG were elevated in the intoxicated lambs. In vivo cellular immunity was assessed by intradermal injection of phytohemagglutinin; the response was lower during intoxication period. These results indicate that a lowering in the average daily gain was the most sensitive indicator of aflatoxicosis in lambs, and that the immune response was altered, which could render the animals more susceptible to infectious diseases.     

Growth and carcass characteristics of lambs in relation to plasma IGF-I and some histological traits of Longissimus lumbarum and Biceps femoris as affected by breed and age at slaughter

Ten male lambs of each of Rahmani (R) and Ossimi (O) were used to study the growth and carcass characteristics within their first year of age (360 days). After suckling period (4 months), lambs were fed on the regular ration. During the course of the experiment, body weight (BW) was recorded monthly accompanied by blood sampling to determine IGF-I. Four lambs from each breed were slaughtered at 270 and 360 days of age, and Longissimus lumbarum (L. lumbarum) at the 9th, 10th and 11th ribs and Biceps femoris (B. femoris) muscles were separated to be used for chemical analysis and histological study.Breed had no effect on the growth curve of the two studied breeds. Chemical analysis indicated that (O) had higher fat (0.9%, P < 0.0001) and lower (0.3%, P < 0.01) moisture compared to (R), with no difference in protein and ash contents. The concentration of IGF-I was almost similar in both breeds up to day 270 of age, and then it was higher in (R). Number of fibers per bundle was higher (P < 0.05) in (O) than in (R) by 6.1%, while, the other histological traits were similar in the two studied breeds.Chemical analysis indicated that lambs slaughtered at 360 days of age had lower (0.7%, P < 0.0006) moisture and higher fat (17.3%, P < 0.0001) compared to day 270. Up to day 270 of age, IGF-I concentration was < 500 ng/ml before increasing to > 500 ng/ml up to the end of the experiment. No effect of age was observed on the studied histological traits.L. lumbarum muscle contained higher protein (4.2%, P < 0.0001), fat (104%, P < 0.0001) and ash (10%, P < 0.001), while moisture was less (5.6%, P < 0.0001) compared to B. femoris muscle. B. femoris muscle was higher (P < 0.0001) in number and diameter of fibers, bundle and stroma sectional areas relative to L. lumbarum by 38.2, 78.8, 53.2 and 23.8%, respectively.     

Effects of Ca salt supplementation on milk yield and composition and on lamb growth rate of Awassi ewes

An experiment was conducted to evaluate the effect of a Ca salt supplement on lactating Awassi ewes and their lambs. Ninety Awassi ewes (average BW = 55 kg ± 1.13) were allocated into three treatment groups of 30 each; 0%, 3%, or 5% Ca salt supplemented groups. The experiment started at lambing and lasted for 60 d. During this period, milk production and composition, final body weights, total feed intake, serum cholesterol and triglycerides, weaning weights of lambs, and milk fatty acid profile were tested. Milk production and energy corrected milk increased (P < 0.05) with Ca salt level in the diet. Milk fat content was higher (P < 0.05) at 3% treatment group compared to 0% and 5% treatment groups. However, no differences were detected in content of crude protein and total solids, and milk energy value. Milk fat yield (g/d) increased (P < 0.05) as Ca salt in the diet increased. Final body weight was higher (P < 0.05) for 5% group when compared to the 0% group with no differences between the 3% group when compared to 0% and 5% groups. No differences were observed in feed intake of ewes. Metabolizable energy intake was greater (P < 0.05) for the 3% and the 5% treatment groups when compared to the 0% treatment group. Feed to milk ratio increased (P < 0.05) when increasing the level of Ca salt in the diet. Serum cholesterol was greater (P < 0.05) in the 5% treatment group than the 0% and 3% treatment groups for ewes and lambs. Serum triglyceride was similar among treatment groups in ewes whereas serum triglyceride was greater (P < 0.05) for lambs in 5% treatment group than 0% and 3% treatment groups. However, serum triglyceride was similar in ewes among treatment groups. Weaning weights and average daily gain of male lambs were higher (P < 0.05) in lambs fed Ca salt (3% and 5%) when compared to 0% treatment group. No differences were detected in weaning weights and average daily gain of female lambs among treatment groups. However, milk conversion ratio was better (P < 0.05) for the 5% group lambs than the 0% and 3% treatment groups. Ca salt reduced (P < 0.05) short and medium-chain milk fatty acids and increased (P < 0.05) content of long chain and unsaturated ones. These results of this indicate that Ca salt supplementation can improve milk production of lactating ewes, the growth rate of their lambs, and produce healthy quality value milk.     

Protein digestibility of porcine colostrum by neonatal pigs

Colostrum plays an important role in neonatal growth and development. However, little is known about the digestion of macronutrients in colostrum of any species. This study was conducted with the neonatal piglet model to determine the digestibility of proteins in porcine colostrum. Twelve, 1-d-old, male piglets were selected from 3 litters (4 pigs/litter) and housed individually in metabolism crates with heating lamps to maintain a temperature of 35 °C. Colostrum (13 L) was collected from 400 sows (30 to 40 mL/sow) within 12 h postpartum after injection of oxytocin. All piglets were fed colostrum containing 0.25% (DM basis) chromium oxide as an external marker based on the following feeding program: 6 meals/d for an entire 3-d period; with 40 mL/meal for d 1 (240 mL/d), 55 mL/meal for d 2 (330 mL/d), and 70 mL/meal for d 3 (420 mL/d). Colostrum was hand-fed using baby milk bottles. Entire fecal samples with the chromium green color were collected each day after colostrum feeding. Fecal collection was terminated before the fading of the green color. Fecal samples were weighed (10.3 ± 1.0 g/pig), stored in − 20 °C, freeze-dried, and thoroughly ground for chemical analysis. Blood samples were collected at 0900 h of d 3 to obtain plasma samples for amino acid and immunoglobulin (Ig) G analysis. Digestibilities of crude protein and DM in colostrum, defined as the percentage of ingested colostral crude proteins and DM that disappeared in the gut, averaged 96.9 ± 0.4% and 98.3 ± 0.2%, respectively. Digestibility of total amino acids (protein-bound plus free amino acids) in the colostrum was 98.3 ± 0.1%, with the values being 98.5 ± 0.3, 98.2 ± 0.4, and 98.3 ± 0.3%, respectively, for Lys, Thr, and Arg. Plasma and colostral IgG content were 3.4 ± 0.3 and 3.8 ± 0.7 g/L, respectively. In conclusion, protein-bound and free amino acids in porcine colostrum were highly digestible and available to neonatal pigs.     

The physical state and metabolic status of lambs of different birth rank soon after birth

This study investigated the physical state and metabolic status of lambs of different birth ranks soon after birth. The aim was to identify the factors that result in poorer survival rates in triplet than single or twin lambs. Six hundred and twenty one Romney ewes were mated over a 4-day period and 46 of them were observed continually from day 143 of pregnancy until they finished lambing. Blood samples, taken from all lambs within 5 min of birth, were placed on ice, centrifuged and the plasma harvested and subsequently analysed for glucose, fructose, lactate, thyroxine (T4) and gamma-glutamyl transferase (GGT). The rectal temperature of each lamb was recorded at birth and at 1, 2, 3 and 6 h of life. Lambs were weighed and measured at 3 h of age.At birth, triplet lambs were significantly lighter (P < 0.05) and had lower (P < 0.05) plasma fructose and thyroxine than twin and single lambs, higher (P < 0.05) lactate concentrations and a lower rectal temperature (P < 0.05) than twin lambs. These observations suggest that they are subject to placental insufficiency. The packed cell volume was significantly (P < 0.001) higher in twin than triplet lambs. The order at birth of twin or triplet lambs had no effect on birthweight or plasma metabolite concentrations. The smallest triplet was significantly lighter (P < 0.05) and had higher plasma lactate (P < 0.05) concentration than the largest triplet.These physiological limitations found in smaller triplet lambs at birth leave them prone to perinatal mortality. Management techniques, to increase triplet lamb birthweight and thereby improve their survival outcome need further investigation.     

The effects of diet and age on serum complement system activity in goat kids

Thirty new born male kids were allotted into three groups to evaluate the effects of diet and age on complement system activity in serum. After the colostrum feeding period, the control group (C) received a commercial milk replacer; the CLA group received 20 g/kg milk replacer DM of conjugated linoleic acid; and the GMK group was fed with goat milk. The kids were fed colostrum for 2 days and then either milk replacer or goat milk from days 3 to 60. Blood samples were taken at 1, 10, 20, 30, 40, 50 and 60 days of age. The complement system activity was higher (P < 0.05) in the GMK group throughout the whole experiment through alternative pathway. C kids did not present complement activity at any time. CLA group complement activity was statistically higher than that of C kids from 30 to 60 days, through alternative pathways. In conclusion, the milk replacer formula should be reformulated because it did not induce any complement system activity in the first two months of life.     

Colostrum production by primiparous and multiparous Holstein dairy cows and its usefulness as an estimator of full lactation milk yield

This study determined colostrum production of lactating primiparous and multiparous Holstein dairy cows, as well as the predictability of full lactation milk yield based upon this colostrum production. Holstein cows that calved between December 18, 2006 and December 24, 2007 (n = 134) had their first two post-partum milkings weighed and assayed for density. Cows then entered normal production groups and were assessed for milk yield and milk components every 4 or 5 weeks for the duration of their lactation. Primiparous cows produced less colostrum (10.6 versus 13.6 kg; P = 0.02) and density adjusted (DA) colostrum (5.2 versus 8.5 kg; P < 0.01), but there were no differences in estimated 305 day mature equivalent (305ME) milk production (mean = 13,654 kg) or lactation lengths (mean = 301 days) between parities. Colostrum and DA colostrum were poor estimators of subsequent 305ME milk production within primiparous cows (r² = 0.20 and 0.01 respectively) and multiparous cows (r² = 0.18 and 0.12 respectively). Colostrum production of these high producing cows was somewhat lower than expected, highly variable among cows within parity, higher for multiparous versus primiparous cows, and was not a good estimator of subsequent 305ME milk production.     

Influence of colostrum treated by heat on immunity function in goat kids

The aim was to evaluate the influence of goat colostrum treated by heat on immune function in kids. Thirteen newborn kids were fed untreated colostrum (group A) and 13 kids were fed colostrum treated by heat (56 degrees C, 30 min) (group B). Blood samples were obtained at eight time points between the ages of 0 h to 28 days. Serum protein fractions, IgG levels and phagocytic activity of neutrophils were determined. A delayed type hypersensitivity (DTH) test was used, clinical status and body weight was recorded. There were no clinical signs of disease and no differences (P>0.05) on body weight between groups were noted. Kids from group B had less total protein levels and gamma-globulins than kids from group A (P<0.05). A decrease in serum IgG levels (P<0.05) was observed in kids from group B during all experiment. DTH response in kids from group B was lower (P<0.01) than group A, suggesting alteration on cellular immune system. No effects on phagocytic activity of the neutrophils were observed when both groups were compared (P>0.05). These results showed that colostrum treated by heat impaired some immunological parameters in kids, but these changes did not affect on clinical status or performance.     

Carcass tissue composition in light lambs: Influence of feeding system and prediction equations

Fourty-eight Churra Tensina single male lambs were used to evaluate the effect of different feeding systems on carcass composition and predict the carcass tissue composition from joint composition and carcass measurements. Four treatments were studied: GR, unweaned lambs continuously grazing with ewes; GR + S, the same as the previous group, but lambs had free access to concentrate; DRL-GRE, lambs remained indoors with free access to concentrate and ewes grazed for 8 h/day, thereafter remaining with lambs; and DRL, lambs and ewes were kept in confinement, they had free access to concentrate and dry unifeed respectively. In the DRL-GRE and DRL groups lambs were weaned when 45 days old. Lambs were slaughtered at 22–24 kg live weight. Commercial joints from the half left carcass were obtained, recorded and dissected to determine carcass tissue composition.The feeding system had an effect on the proportion of the carcass tissue composition. GR treatment showed higher muscle (M) (p < 0.05) and bone (B) (p < 0.001) percentages, and a lower total fat (F) percentage (p < 0.001) than the rest of treatments. Hence it revealed higher M/F (p < 0.01) and lower M/B (p < 0.05) and subcutaneous fat/intermuscular fat ratios (SF/IF; p < 0.001). Carcass composition predictions were more accurate for grams than for percentages. In predictions from joint composition, pelvic limb was the most accurate joint for grams (R² = 0.84, R² = 0.68, and R² = 0.77 for muscle, bone, and fat, respectively) as well as for percentage (R² = 0.65, R² = 0.56, and R² = 0.73 for muscle, bone, and fat, respectively). Predictions from carcass measurements were greater in muscle and fat grams (R² = 0.87 and R² = 0.86 for muscle and fat, respectively) than in percentage (R² = 0.58 and R² = 0.73 for muscle and fat, respectively). Equations to predict carcass tissue that include carcass measurements are a simple method to assess accurately saleable muscle yield from different lamb feeding systems without involving carcass damage.     

Blood and colostrum/milk serum gamma-glutamyltransferase activity as a predictor of passive transfer status in lambs

The importance of blood and colostrum/milk serum gamma-glutamyl transferase (gamma-GT) enzyme activity was evaluated to assess passive transfer status in healthy lambs. Thirty Akkaraman sheep (3-6 years old) were used which had normal pregnancy period and the same conditions, and the age of the lambs ranged between 0 and 15 days. Blood and colostrum/milk samples were collected from sheep and lambs after birth, before suckling (0) and after on 1st, 3rd, 7th and 15th days. Serum immunoglobulin G (IgG) concentration was determined by the use of Single Radial Immunodiffusion method. Serum gamma-GT activity was measured, using a commercially available kit in blood and colostrum/milk samples. Correlations were carried out between immunoglobulin and gamma-GT levels. Regression models (simple and multiple) were calculated with significant data. Linear correlation was determined between colostrum/milk gamma-GT activity and IgG concentrations and between serum gamma-GT activity and IgG concentrations in lambs on the 0 day. (r: 0.607, P: 0.001), 1st (r: 0.768, P: 0.001) and the 3rd (r: 0.603, P: 0.001) days and on the 1st (r: 0.637, P: 0.001) and 3rd (r: 0.478, P: 0.012) days in the experiment, respectively. Multivariate regression models were developed to estimate sample IgG concentration. Serum and colostrum/milk IgG concentration could be predicted using the formula: lamb serum IgG = 825 + 0.688 (lamb gamma-GT) + 52 (days); colostrum/milk IgG = 832 + 0.505 (colostrum/milk gamma-GT) - 167 (days). The regression models were moderately accurate in predicting serum IgG concentration (R2 = 0.51) and colostrum/milk IgG concentration (R2 = 0.55). Test sensitivity and positive predictive values for serum gamma-GT enzyme activity were found to be 96 and 100% and for colostrum/milk gamma-GT enzyme activity were found to be 100 and 68% to prediction IgG concentration. Serum and colostrum/milk gamma-GT activity can be used to assess passive transfer status of lambs. Along with this, regression models used to calculate serum and colostrum/milk gamma-GT activities found to be useful to estimate sample IgG concentration. The use of serum and colostrum/milk gamma-GT enzyme activity was found useful especially after birth on the 0, 1st and 3rd days.     

Carcass characteristics of Awassi ram lambs slaughtered at different weights

Thirty Awassi ram lambs were used to study the effects of slaughter weight on carcass characteristics. Lambs were slaughtered at three different live weights (20, 30, and 40 kg). Empty body weight, hot and cold carcass weights and non-carcass components increased (P < 0.001) at a steady rate between all slaughter weights. Body length, leg length, maximum shoulder width, width behind shoulders and gigot width increased (P < 0.001) as slaughter weight increased from 20 to 40 kg. Linear dimensions measured on the surface of the M. Longissimus also increased (P < 0.001) with increasing slaughter weight. The ratio between width and depth of the longissimus muscle decreased (P < 0.01) at a steady rate between 20 and 40 kg indicating that the muscle increased more in depth than width. Dressing-out percentage was higher (P < 0.001) for lambs slaughtered at 30 kg live weight compared to other weights. Total lean and total bone decreased (P < 0.05) as a percent of cold carcass weight while total fat, subcutaneous and intermuscular fat percentages increased (P < 0.05) with increasing weight. Subcutaneous fat percentage was not affected by increasing body weight between 20 and 30 kg. Intermuscular fat percent was higher in all cuts except the leg where subcutaneous fat % was higher. Muscle to bone ratio increased (P < 0.001) while muscle to fat ratio decreased (P < 0.001) with increasing body weight in the four major cuts and the whole carcass. In conclusion, slaughtering Awassi ram lambs at weights up to 30 kg resulted in higher dressing-out percentage and better carcass characteristics than ram lambs slaughtered at heavier weights.     

Colostrum yield and litter performance in multiparous sows subjected to farrowing induction

The consumption of colostrum at a low level can compromise the survival and growth of piglets. Therefore, this study aimed to evaluate the effect of farrowing induction on colostrum yield, IgG concentration and the survival and performance of piglets until the weaning. Sows of parity 3 to 7 were assigned into two groups: Control (n = 48), sows with spontaneous farrowing; and induction (n = 48), sows induced to farrow on day 114 of gestation with a PGF₂ analogue. Colostrum and blood samples were collected from the sows, at farrowing and 24 hr later. Blood samples from the piglets were collected at 24 hr after birth. The performance of the piglets was evaluated in a subsample of 28 litters from each group. All piglets were weighed at 7, 14 and 20 days of age. The farrowing length, the number of piglets born alive, stillborn piglets, weight at birth, litter weight at birth and colostrum yield were not significantly affected (p > .05) by farrowing induction. There was no difference between the groups (p > .05) in the percentage of sows with obstetric interventions. Serum IgG concentration, in both sows and piglets, and colostrum IgG concentration were similar between the groups (p > .05). Furthermore, survival rate, piglet weight and litter weight at 7, 14 and 20 days of age were also similar between the groups (p > .05). Therefore, it can be concluded that the farrowing induction performed on day 114 of gestation does not affect the colostrum yield, the IgG concentration in colostrum and serum of piglets, and the litter performance until the weaning.     

Mammary Secretion of IgG in Sows

The IgG-concentration was determined in serum of 3 pregnant sows before and after partus and in colostrum of 7 sows 0–6 days post partum. The IgG-concentration decreased in serum before partus and increased after partus. The lowest value (1.5 g/100 ml) was observed at partus. The results indicate that IgG is transmitted from serum to colostrum.The concentration of IgG in colostrum was found to be 2.1–10.4 g/100 ml at partus. The concentration decreased very fast during the first day post partum. During 3–6 days post partum the IgG concentration was rather constant (0.3–0.5 g/100 ml). The importance of the results for the passive immunization of piglets is discussed.     

Acanthopanax senticosus extract as a dietary additive enhances the apparent ileal digestibility of amino acids in weaned piglets

The present study was conducted to determine the effects of Acanthopanax senticosus (AS) extract as a dietary additive on serum contents and apparent ileal digestibility (AID) of amino acids (AA) in weaned piglets. In Exp. 1, 60 piglets with an average body weight (BW) of 5.64 kg were randomly assigned into 3 treatment groups who received maize-soybean-based diets supplemented with 0 or 1 g/kg of AS extract or 0.2 g/kg of colistin (n = 20 in each group). Blood samples were randomly collected from 5 piglets per group on days 7, 14 and 28 after the initiation of supplementation to determine the serum contents of free AA. In Exp. 2, 12 barrows with an average initial BW of 7.64 kg were also randomly assigned into 3 dietary treatment groups after being surgically fitted with a simple T-cannula at the terminal ileum. Samples of terminal ileal digesta were collected on day 7 for analysis of the AID of AA. The data showed that the serum contents and AID of most AA in the AS extract-supplemented group gradually increased by 15.3–80.8% and 4.1–30.8%, respectively, as the experiment proceeded in comparison with the colistin-supplemented group and/or control group. In conclusion, these findings indicated that AS extract could enhance the digestion and absorption of AA, which may be a potential mechanism of growth promotion.     

Alfalfa as a supplement of dried cornstalk diets: Associative effects on intake, digestibility, nitrogen metabolisation, rumen environment and hematological parameters in sheep

The aim of the current study was to investigate the associative effects of a cornstalk-based diet supplemented with alfalfa (Medicago sativa) hay on intake, digestibility, nitrogen (N) metabolisation, rumen environment and hematological parameters in Xiaoweihan sheep. We also investigated the optimal range of alfalfa hay to achieve positive associative effects and avoid negative effects. Xiaoweihan sheep (n = 5; fitted with rumen T-cannula) were fed five cornstalk-based diets in a 5 × 5 Latin square design. Diets contained 0, 50, 150, 300, 450 g alfalfa, and were supplemented with 100 g concentrate, respectively. Our results suggested that supplementation of 300 g alfalfa hay reduced (P < 0.05) cornstalk intake, but significantly increased dry matter (DM) intake (P < 0.05). Additionally, DM digestibility of 150 g alfalfa hay supplementation was slightly higher than that noted in other diets. Metabolism studies showed 50–150 g alfalfa hay supplementation had a positive associative effect (P < 0.05) on N utilization, with the greatest benefit noted with 150 g per day (P < 0.05) compared to unsupplemented diets. Alfalfa supplementation (50–450 g per day) resulted in an elevated trend of ammonia nitrogen (NH₃–N) with 50 or 150 g of alfalfa hay more likely to promote sheep rumen environment, with a noticeable increase (P < 0.05) in serum urea nitrogen (UREAN) concentrations observed with 300 g alfalfa hay per day. Our data suggested that the optimal range to achieve beneficial effects and avoid negative effects was 150–300 g per day for cornstalk-based diets for sheep.     

Calcium homeostasis, acid–base balance, and health status in periparturient Holstein cows fed diets with low cation–anion difference

Forty multiparous Holstein dry cows on d 21 prepartum were randomly allocated to four blocks of 10 cows to examine the effects of reducing the dietary cation–anion difference (DCAD) on calcium homeostasis, acid–base balance, health status, and subsequent lactation performance. The reduced DCADs (Na + K − Cl − S, mEq/kg DM) of + 150,+ 50, − 50, and − 150 were obtained by addition of anionic salts. Reducing DCAD resulted in mild metabolic acidosis as indicated by the sharp decline in urinary pH, and minor reductions in blood pH and HCO₃⁻ concentration. Greater plasma calcium concentration was observed in cows fed diets of − 50 and − 150 DCAD (P < 0.05) than those on + 50 and + 150 DCAD diets. The nadir of plasma calcium level on the day of calving was lower (P < 0.05) than the highest level on d 14 prepartum (8.33 vs. 9.30 mg/dL). Composite colostrum calcium concentration was decreased (P < 0.05) with time on d 1 relative to d 2 postpartum (0.212 vs. 0.174%), and feeding of diet − 150 DCAD induced higher (P < 0.05) composite colostrum calcium content than other three DCAD diets. No case of milk fever occurred for any diets, but feeding the two negative DCAD diets reduced (P < 0.05) retained placenta incidence compared with diet of + 150 DCAD. Dry matter intake, milk yield and compositions of fat, protein, and lactose were non-significantly affected (P > 0.05) by dietary treatments. In conclusion, urinary pH is an effective indicator of extracellular fluid acid–base balance, and feeding negative DCAD in late gestation period is beneficial for dairy cows in blood calcium homeostasis and improvement of health status.     

Effect of addition of soybean trypsin inhibitor to colostrum on immunological status in goat kids

The aim of the study was to evaluate the influence of soybean trypsin inhibitor (TI) on immunoglobulin G (IgG) serum levels and growth in neonatal goat kids. Twenty‐four newborn kids were fed with natural colostrum (group A), and 24 kids received the same colostrum with 1 g of TI per litre (group B). Blood samples were obtained at birth and on days 1, 2 and 4 of life to analyze serum proteins, IgG and haematological parameters. There were no clinical signs of disease and no significant differences in body weight between the groups. Haematological parameters were not affected by treatment. The peak of serum IgG was reached at 24 h of life, but no effects of soybean TI was observed on serum IgG levels. The apparent efficiency of absorption of IgG was similar in both groups (group A 24.5% vs. group B 25.2%, p > 0.05). The addition of TI to colostrum did not change the concentration of serum proteins and their fractions in goat kids. The correlation between serum IgG and γ‐globulin was positive and significant (p < 0.01, r = 0.64) in group A, but not in group B (p > 0.05, r = 0.08), suggesting a negative influence of soybean TI on γ‐globulin absorption. These results show that addition of soybean TI to colostrum did not improve the performance or immunological status in goat kids.     

Energy balance, milk production and reproduction in grazing crossbred cows in the tropics with and without cereal supplementation

The aim of this work was to study the effect of parity order and reproductive management systems on rabbit production performance. A total of 73 rabbit does (I group) were submitted to a 35-day intensive rhythm [artificial insemination (AI) on day 4 post-partum (pp) and weaning at 25 days of lactation], and 108 rabbit does (SI group) were submitted to a 42-day semi-intensive rhythm (AI on day 11 pp and weaning at 35 days of lactation) during 9 months. Primiparous does had the lowest live body weight at parturition (P < 0.0001) and at 21 days of lactation (P < 0.0001). They also had lower milk production (P < 0.0001) than does with later parities. I group animals needed a higher number of AI than SI group to become pregnant (1.70 ± 0.03 vs. 1.39 ± 0.03; P < 0.0001: especially after the third). Prolificacy was not affected by the management system. Parturition interval (PI) was longer than expected in both groups [56.0 ± 1.4 and 50.9 ± 1.38 days in I and SI groups, respectively (P < 0.05)]. Mean productivity, estimated as number of weaned rabbits per female and year, was 12 kits higher in rabbit does of the SI group (P < 0.05). From the third parturition onward, an increase in live body weight of kits at different ages was observed. At 21 (P < 0.05) and 25 days of age (P < 0.01), kits from the I group rabbit does weighed more than those from the SI group; however, the latter showed a higher weight at 35 (P < 0.05) and 60 days of age (P < 0.05). Rabbit does with two or three parturitions had higher litter size at 21 and 25 days of age (P < 0.0001 and P < 0.001, respectively). Kit mortality between 21 and 25 days of age and between 35 and 60 days of age was not affected by treatments but was higher in the I group between 25 and 35 days (18.2 vs. 5.03% in the I and SI groups, respectively; P < 0.0001) and as age of does increased (P < 0.05). In light of these results, we could conclude that long term doe reproductive performance is negatively affected and litter viability decreased when using intensive compared to a semi-intensive reproductive management.