Negative effects of energy supplementation at peak lactation of sheep can be offset by the addition of Lactobacillus-fermented plant extracts

Energy supplementation may reduce oxidative stress by correcting a negative energy balance, but in some contexts, it has been shown to increase oxidative stress, especially at peak lactation. The current experiment examined if a pelleted energy supplement with or without the addition of Lactobacillus-fermented seaweed or seaweed plus terrestrial plants extracts affected oxidative stress of ewes from late gestation through to weaning and ewe and lamb production from lambing to weaning. Treatments were either no supplement (CON−), a pelleted supplement only (CON+, 100 g/ewe per d), CON+ with seaweed extract only (SWO, 10 mL/ewe per day), or CON+ with seaweed plus an arrangement of terrestrial plant extract (SWP, 10 mL/ewe per d). Ewes (n = 160; mean initial BW = 72.3 ± 9.5 kg [mean ± SD]) were randomized to pastures (n = 4 pastures per treatment with 10 ewes each). After lambing, ewes with twins were reallocated to pastures (n = 3 pastures per treatment with 10 ewes each) according to lambing date. At 4 wk in milk, supplementation tended to reduce total antioxidant status (TAS; P = 0.10) and increased glutathione peroxidase (GPx) activity compared with nonsupplemented ewes (P = 0.04). The addition of seaweed and terrestrial plants extracts to the concentrate, that is, SWO and SWP, increased TAS and reduced GPx activity compared with CON+ (P < 0.01). Supplementation increased milk yield at weeks 4, 6, and 8 of lactation, and protein, lactose, and total milk solids yield at peak lactation (week 4; P < 0.05). The CON− ewes had greater somatic cell count than the supplemented ewes at weeks 4, 8, and 10 of lactation (P = 0.03). Our results suggest that energy supplementation, alone, increases oxidative stress of lactating ewes, which may relate to increased oxidative phosphorylation. Most importantly, these results indicate that in situations where energy supplementation is needed to increase animal performance, negative effects of energy supplementation around peak lactation can be offset by the addition of Lactobacillus-fermented plant extracts (SWO and SWP) to improve antioxidant status.     

Comparison of performance of F1 Romanov crossbred ewes with wool and hair breeds during fall lambing and body weight and longevity through six production years

The objective of this study was to evaluate wool (Dorset and Rambouillet) and hair (Dorper, Katahdin, and White Dorper) breeds for their ability to complement Romanov germplasm in an annual fall lambing system by estimating direct maternal grandsire and sire breed effects on economically important lamb and ewe traits. After 3 yr of evaluation under spring lambing, ewes of the five F1 types were transitioned to spring mating, exposed to composite terminal sires, and evaluated under a barn lambing system at 4, 5, and 6 yr of age. A total of 527 first generation crossbred (F1) ewes produced 1,151 litters and 2,248 lambs from 1,378 May exposures. After accounting for differences in dam age, birth type, and sex, lamb survival to weaning was unaffected by maternal grandsire breed (P = 0.30). However, lambs born to 50% Dorset (16.8 ± 0.21 kg) or 50% White Dorper ewes (16.8 ± 0.28 kg) were heavier at weaning than those born to 50% Katahdin dams (13.8 ± 0.32 kg; P < 0.001). Additionally, lambs born to 50% Dorset ewes were heavier than those born to 50% Rambouillet (16.0 ± 0.22 kg) and 50% Dorper ewes (15.7 ± 0.33; P ≤ 0.03), but no other pairwise maternal grandsire breed differences were observed (P ≥ 0.06). Ewe body weight (n = 3,629) was recorded prior to each of six possible mating seasons and, across ages, was greatest for Dorset- and Rambouillet-sired ewes (56.7 ± 0.44 and 56.5 ± 0.45 kg, respectively), intermediate for Dorper- and White Dorper-sired ewes (54.7 ± 0.78 and 54.1 ± 0.64 kg, respectively), and least for Katahdin-sired ewes (51.5 ± 0.45 kg). Fertility after spring mating (0.80 ± 0.03 to 0.87 ± 0.02), litter size at birth (1.46 ± 0.09 to 1.71 ± 0.07), and litter size at weaning (1.25 ± 0.06 to 1.46 ± 0.06) were not impacted by sire breed (P ≥ 0.16). Ewe longevity, assessed as the probability of being present after 6 production years, was also not affected by sire breed (0.39 ± 0.03 to 0.47 ± 0.03; P = 0.44). Rambouillet-sired ewes weaned more total weight of lamb (21.5 ± 0.94 kg) than Katahdin-sired ewes (17.8 ± 0.94 kg; P = 0.05), but no other sire breed differences were detected (P ≥ 0.07). Results demonstrated that incorporating the Romanov into a crossbreeding system is a practical means of improving out-of-season ewe productivity.     

Evaluation of Awassi genotypes for improved milk production in Syria

A performance evaluation, conducted between 2003 and 2005, compared the milk production of three genotypes of Awassi ewes: Turkish (T), Syrian (S) and the F1-cross between the Turkish and Syrian ewes (TS), at the International Center for Agricultural Research in the Dry Areas (ICARDA) experimental farm in Tel Hadya (northern Syria). After weaning, which occurred at 56days, milk yield and milking length were measured weekly during the milking period (n = 381). Milk yield of TS and T ewes were 12% and 30% higher, respectively, than S ewes. Milk yield and milking length of TS ewes reflected additive inheritance and did not differ from the parental genotypes' average (p ≥ 0.199). Culling of low producing ewes in 2003 and 2004 also resulted in increased milk yield. Dams of all genotypes displayed similar weights at birth (p = 0.898) and weaning (p ≥ 0.677). The latter suggests dams of the different genotypes olerated equally the pre-weaning lactation load. Performance tended to improve as ewes aged, with milk yield and milking length peaking at 3years of age (p > 0.05). Ewe lambing weight, birth–weaning ewe weight decline, litter size, and litter weight weaned peaked at 4–5years of age (p ≤ 0.016). With the exception of birth–weaning ewe weight decline, year effects influenced the traits under study (p ≤ 0.035). Excluding litter size, the best performance was in 2005, followed by 2003 and 2004. Milk yield increased with litter size at weaning (b = 18.7; p = 0.024). The lambing–weaning ewe weight decline (3.6kg) and ewe productivity (0.46kg litter weaned weight per kg ewe weight) did not differ between genotypes (p ≥ 0.178). Average litter size was 1.15, with the TS ewes displaying the largest litter size (1.23; p = 0.026). Single lambs were 25% heavier than twins at birth averaging 4.73kg and 3.8kg, respectively. Male lambs were 4% heavier than female lambs at birth (p < 0.0001) and 9.3% heavier at weaning (p < 0.0001). Lamb birth weights, weaning weights and daily weight gains were similar for all genotypes (p ≥ 0.210). The average proportion of fat (5.95%), crude protein (5.19%) and solids non-fat (11.29%) in the milk varied across genotypes where S < TS < T (p ≤ 0.0037). F1 crosses with T increased the productivity of S ewes by 12.2%. It is noteworthy that this occurred under improved feeding and may not be recommended for other conditions. Culling low producing ewes led to a 12.8% increase in milk yield, which could translate into a substantial boost in revenue for farmers rearing traditional sheep flocks in milk producing areas.     

Effect of divergence in residual methane emissions on feed intake and efficiency,growth and carcass performance,and indices of rumen fermentation and methane emissions in finishing beef cattle

Residual expressions of enteric emissions favor a more equitable identification of an animal’s methanogenic potential compared with traditional measures of enteric emissions. The objective of this study was to investigate the effect of divergently ranking beef cattle for residual methane emissions (RME) on animal productivity, enteric emissions, and rumen fermentation. Dry matter intake (DMI), growth, feed efficiency, carcass output, and enteric emissions (GreenFeed emissions monitoring system) were recorded on 294 crossbred beef cattle (steers = 135 and heifers = 159; mean age 441 d (SD = 49); initial body weight (BW) of 476 kg (SD = 67)) at the Irish national beef cattle performance test center. Animals were offered a total mixed ration (77% concentrate and 23% forage; 12.6 MJ ME/kg of DM and 12% CP) ad libitum with emissions estimated for 21 d over a mean feed intake measurement period of 91 d. Animals had a mean daily methane emissions (DME) of 229.18 g/d (SD = 45.96), methane yield (MY) of 22.07 g/kg of DMI (SD = 4.06), methane intensity (MI) 0.70 g/kg of carcass weight (SD = 0.15), and RME 0.00 g/d (SD = 0.34). RME was computed as the residuals from a multiple regression model regressing DME on DMI and BW (R² = 0.45). Animals were ranked into three groups namely high RME (>0.5 SD above the mean), medium RME (±0.5 SD above/below the mean), and low RME (>0.5 SD below the mean). Low RME animals produced 17.6% and 30.4% less (P < 0.05) DME compared with medium and high RME animals, respectively. A ~30% reduction in MY and MI was detected in low versus high RME animals. Positive correlations were apparent among all methane traits with RME most highly associated with (r = 0.86) DME. MY and MI were correlated (P < 0.05) with DMI, growth, feed efficiency, and carcass output. High RME had lower (P < 0.05) ruminal propionate compared with low RME animals and increased (P < 0.05) butyrate compared with medium and low RME animals. Propionate was negatively associated (P < 0.05) with all methane traits. Greater acetate:propionate ratio was associated with higher RME (r = 0.18; P < 0.05). Under the ad libitum feeding regime deployed here, RME was the best predictor of DME and only methane trait independent of animal productivity. Ranking animals on RME presents the opportunity to exploit interanimal variation in enteric emissions as well as providing a more equitable index of the methanogenic potential of an animal on which to investigate the underlying biological regulatory mechanisms.     

Environmental factors that influence milk production of Pantaneiro ewes and the weight gain of their lambs during the pre-weaning period

The main objective of this research was to conduct an exploratory study of the lactation curve in order to characterize the productive potential of Pantaneiro ewes and lambs. Fifty ewes were bred using four rams in two different mating seasons. The ewes were kept with their lambs on pasture of Brachiaria brizantha. Ewe body score, ewe weight, and lamb weight were evaluated. Milk sampling was performed every week. In the morning for milk collections, the ewes were treated with 1 UI of oxytocin (intramuscular) for complete milking. Lambs were separated from the ewes for 4 h and milk collections were performed. The total milk production over 24 h was estimated by multiplying the production of this period (4 h) by 6. The data were analyzed using the MIXED procedure (P?<?0.05) in SAS. Milk production data were fitted to the curve using the incomplete gamma function of Wood, and lamb growth data were fitted using the Gompertiz equation. The average milk production of the ewes was 1.03 kg/day^?1. Younger ewes had the lowest milk production (18?=?798?±?330, 24?=?1001?±?440, 36?=?1100?±?490, and 48?=?1106?±?490 g/day^?1). Ewe body score at lambing affected initial milk production (1.0?=?816?±?660, 1.5?=?1089?±?105, and 2.0?=?1424?±?1600 g/day^?1). Lambs were weaned with an average weight of 20.3 kg. Daily weight gain from birth to weaning was 181 g. Locally adapted Pantaneiro ewes showed a linear decreasing lactation curve, with reduced production from the second week of lactation. Overall, evaluation of the dairy production and lamb performance revealed great variation, denoting potential for selection.     

Effects of serine palmitoyltransferase inhibition by myriocin in ad libitum-fed and nutrient-restricted ewes

The fungal isolate myriocin inhibits serine palmitoyltransferase and de novo ceramide synthesis in rodents; however, the effects of myriocin on ceramide concentrations and metabolism have not been previously investigated in ruminants. In our study, 12 non-lactating crossbred ewes received an intravenous bolus of myriocin (0, 0.1, 0.3, or 1.0 mg/kg/body weight [BW]; CON, LOW, MOD, or HIGH) every 48 h for 17 d. Ewes consumed a high-energy diet from day 1 to 14 and were nutrient-restricted (straw only) from day 15 to 17. Blood was collected preprandial and at 1, 6, and 12 h relative to bolus and nutrient restriction. Tissues were collected following euthanasia on day 17. Plasma was analyzed for free fatty acids (FFAs), glucose, and insulin. Plasma and tissue ceramides were quantified using mass spectrometry. HIGH selectively decreased metabolizable energy intake, BW, and plasma insulin, and increased plasma FFA (Dose, P < 0.05). Myriocin linearly decreased plasma very-long-chain (VLC) ceramide and dihydroceramide (DHCer) by day 13 (Linear, P < 0.05). During nutrient restriction, fold-change in FFA was lower with increasing dose (P < 0.05). Nutrient restriction increased plasma C16:0-Cer, an effect suppressed by MOD and HIGH (Dose × Time, P < 0.05). Myriocin linearly decreased most ceramide and DHCer species in the liver and omental and mesenteric adipose, VLC ceramide and DHCer in the pancreas, and C18:0-Cer in skeletal muscle and subcutaneous adipose tissue (Linear, P ≤ 0.05). We conclude that the intravenous delivery of 0.3 mg of myriocin/kg of BW/48 h decreases circulating and tissue ceramide without modifying energy intake in ruminants.     

Effects of birth weight and dietary fat on intake,body composition,and plasma thyroxine in neonatal lambs

Intrauterine growth restriction (IUGR) is often observed in one of the fetuses carried by well-fed prolific ewes. This condition is the result of an insufficient placental size to cover the nutritional needs of the fetus during the near exponential growth phase of the last trimester. After birth, these IUGR offspring have an elevated appetite and lower maintenance energy requirements, suggesting dysregulation of homeostatic systems governing energy metabolism. It is also unknown whether the consequent increase in fatness occurs similarly in both visceral and carcass fractions. To address these questions, lambs differing in birth size (BS, IUGR vs. Normal, 2.6 ± 0.05 vs. 4.2 ± 0.07 kg, P < 0.001) were offered unlimited amounts of a low fat [LF; 22% of dry matter (DM)] or a high fat (HF; 38% of DM) milk replacer and slaughtered on day 14 of postnatal age (n = 7 to 8 for each BS × Diet); a second group of IUGR lambs (n = 3 for each diet) was slaughtered when they reached 8.5 kg, corresponding to the weight of Normal lambs on day 14. When normalized to body weight (BW), the DM and energy intake of IUGR lambs were higher than those of Normal lambs over the first 14 d of life (BS, P < 0.01), but contrary to expectations, the HF diet did not exacerbate these effects of the IUGR condition. Intrauterine growth restricted lambs had increased viscera fat with both diets (BS and Diet, P < 0.05) but increased carcass fat only with the LF diet (BS × Diet, P = 0.08); the fatness promoting effect of the IUGR condition was increased in both body fractions when lamb groups were compared at the fixed BW of 8.5 kg. A subset of metabolic hormones was analyzed, including the metabolic rate-setting hormone thyroxine (T4) and its possible positive regulator leptin. Plasma T4 was lower in IUGR than in Normal lambs at birth (P < 0.05) but then disappeared by day 7 of postnatal life (BS × Day, P < 0.01). On the other hand, the HF diet had no effect on plasma T4 over the first 3 d but caused an increase, irrespective of BS by day 11 (Diet × Day, P < 0.001). Plasma leptin increased with dietary fat and time (P < 0.06) but bore no relation to the effects of BS or Diet on plasma T4. These data show that IUGR and Normal lambs are similarly unable to adjust caloric intake in early life and that the fatness promoting effects of the IUGR condition are more pronounced in the viscera than in the carcass. These data also reveal dynamic regulation of plasma T4 by BS and Diet in neonatal lambs.     

Effect of a carbohydrase admixture in growing pigs fed wheat-based diets in thermoneutral and heat stress conditions

The efficacy of exogenous carbohydrases in pig diets has been suggested to depend on enzyme activity and dietary fiber composition, but recent evidence suggests other factors such as ambient temperature might be important as well. Therefore, we investigated the effect of heat stress (HS) on the efficacy of a multienzyme carbohydrase blend in growing pigs. Ninety-six (barrows: gilts; 1:1) growing pigs with initial body weight (BW) of 20.15 ± 0.18 kg were randomly assigned to six treatments, with eight replicates of two pigs per pen in a 3 × 2 factorial arrangement: three levels of carbohydrase (0, 1X, or 2X) at two environmental temperatures (20 °C or cyclical 28 °C nighttime and 35 °C day time). The 1X dose (50 g/tonne) provided 1,250 viscosimetry unit (visco-units) endo-β-1,4-xylanase, 4,600 units α-l-arabinofuranosidase and 860 visco-units endo-1,3(4)-β-glucanase per kilogram of feed. Pigs were fed ad libitum for 28 d and 1 pig per pen was sacrificed on day 28. There was no enzyme × temperature interaction on any response criteria; thus, only main effects are reported. Enzyme treatment quadratically increased (P < 0.05) BW on day 28, average daily gain (ADG) (P < 0.05), and average daily feed intake (ADFI) (P < 0.05) with the 1X level being highest. HS reduced the BW at day 14 (P < 0.01) and day 28 (P < 0.01), ADG (P < 0.01), and ADFI (P<0.001). There was a trend of increased feed efficiency (G:F) (P < 0.1) in the HS pigs. HS increased apparent jejunal digestibility of energy (P < 0.05) and apparent ileal digestibility of calcium (P < 0.01). At day 1, HS reduced serum glucose (P < 0.001) but increased nonesterified fatty acid (P < 0.01). In the jejunum, there was a trend of increased villi height by carbohydrases (P < 0.1), whereas HS reduced villi height (P < 0.05). HS increased the jejunal mRNA abundance of IL1β in the jejunum (P < 0.001). There was a trend for a reduction in ileal MUC2 (P < 0.1) and occludin (P < 0.1) by HS, and a trend for increased PEPT1 (P < 0.1). There was no effect of HS on alpha diversity and beta diversity of the fecal microbiome, but there was an increase in the abundance of pathogenic bacteria in the HS group. In conclusion, HS did not alter the efficacy of carbohydrases. This suggests that carbohydrases and HS modulate pig performance independently.     

Mammary gland growth and vascularity at parturition and during lactation in primiparous ewes fed differing levels of selenium and nutritional plane during gestation

Background

Objectives were to examine the effects of selenium (Se) supply and maternal nutritional plane during gestation on mammary gland growth, cellular proliferation, and vascularity at parturition and d 20 of lactation. Rambouillet primiparous ewes (n = 84) were allocated to treatments in a 2 x 3 factorial. Factors were dietary Se (adequate Se [ASe, 11.5 μg/kg BW] or high Se [HSe, 77.0 μg/kg BW]) and nutritional plane (60% [RES], 100% [CON], or 140% [EXC]). At parturition, lambs were removed and 42 ewes (7/treatment) were necropsied. Remaining ewes were fed a common diet meeting requirements for lactation and mechanically milked twice daily until necropsy on d 20. At both necropsy periods, mammary glands were dissected and tissues harvested. Samples were analyzed for RNA, DNA, and protein content, cell proliferation, and vascularity. Where interactions were present (P ≤ 0.05), least squares means from the highest-order interaction are presented.

Results

Final body weight of ewes was least (P ≤ 0.002) in RES, intermediate for CON, and greatest for EXC, regardless of stage of the ewe at necropsy (parturition or d 20 of lactation). In ewes necropsied at parturition, mammary glands were heavier (P = 0.02) in EXC compared to RES, with CON intermediate. Concentration of RNA (mg/g) was decreased (P = 0.01) in EXC compared to CON at parturition. There was a tendency (P = 0.07) for a Se by nutrition interaction in percentage of cells proliferating where ASe-EXC ewes had greater (P ≤ 0.02) number of proliferating cells then all other treatments. Mammary vascular area tended (P = 0.08) to be affected by a Se by nutrition interaction where ASe-CON had less (P = 0.007) vascular area than HSe-CON ewes. In ewes necropsied at d 20 of lactation, the number of alveoli per area was decreased (P ≤ 0.05) in RES compared to CON and EXC-fed ewes.

Conclusions

Results of this study indicate that proper maternal nutritional plane during gestation is important for mammary gland development, even out to d 20 of lactation.     

Effects of magnesium on the performance of sows and their piglets

The objective of this study was to evaluate the effects of supplemental magnesium (Mg) on the performance of gilts and parity 3 sows and their piglets. Fifty-six gilts (Trial 1) and 56 sows (Trial 2) were assigned to one of 4 treatments according to their mating weight, respectively. The treatments comprised corn-soybean meal based gestation and lactation diets (0.21% magnesium) supplemented with 0, 0.015, 0.03, or 0.045% Mg from mating until weaning. The results showed that magnesium supplementation significantly (P < 0.05) reduced the weaning to estrus interval in both gilts and sows. There were significant effects (P < 0.05) of supplemental magnesium on the total number of piglets born, born alive and weaned in sows. In late gestation and lactation, the digestibility of crude fiber (quadratic effects, P < 0.05), and crude protein (P < 0.05), were significantly influenced by magnesium in gilts and sows, respectively. There were differences among the 4 groups in terms of the apparent digestibility of dry matter and crude fiber in sows (P < 0.05) during both early and late gestation. The apparent digestibility of gross energy was increased for sows in late gestation (P < 0.05), and lactation (quadratic effects, P < 0.05). At farrowing and weaning, serum prolactin levels and alkaline phosphate activities linearly increased in sows as the Mg supplementation increased (P < 0.05). Serum Mg of sows at farrowing and serum urea nitrogen of sows at weaning was significantly influenced by Mg supplementation (P < 0.05). The Mg concentration in sow colostrum and the serum of their piglets were increased by supplemental magnesium (P < 0.05). In addition, growth hormone levels were linearly elevated (P < 0.05) in the serum of piglets suckling sows. Our data demonstrated that supplemental magnesium has the potential to improve the reproduction performance of sows, and the suitable supplemental dose ranged from 0.015% to 0.03%.     

Effect of Brazilian red propolis administration on hematological, biochemical variables and parasitic response of Santa Inês ewes during and after flushing period

Brazilian red propolis was administered orally to Santa Inês ewes, and evaluation was made of general health and hematological, biochemical, and parasitic responses during and after flushing. Thirty mature, nonlactating, nonpregnant Santa Inês ewes (40?±?2 kg and 2.5 years old) were grazing tropical pasture (Brachiaria decumbens and Pennisetum purpureum) and, as flushing after synchronization, were supplemented with a concentrate–roughage mixture at a rate of 4 % body weight (BW). Ewes were divided according to BW and fecal egg count (FEC) into two groups (n?=?15 each): control and propolis that received propolis ethanolic extract at rates of, respectively, 0 and 3 g/ewe/day. The treatments lasted 21 days until the end of flushing period. BW and body condition score (BCS) were recorded, and blood and fecal samples were taken weekly for 8 weeks. Mean values of BW and BCS were not (P?>?0.05) affected by propolis administration. Propolis increased (P?<?0.01) total leukocytes (WBC), but no significant differences were observed for other hematological parameters. Propolis increased (P?<?0.01) total protein and globulin concentrations and decreased (P?<?0.01) triglycerides, glutamate oxaloacetate transaminase, and glutamate pyruvate transaminase. Propolis decreased (P?<?0.05) FEC. Propolis administration had good impact on ewe health and may be a promising feed additive during critical periods such as flushing.     

Assessment of visceral organ growth in pigs from birth through 150 kg

Visceral organs (VO) are essential for their role in the metabolism and distribution of consumed nutrients as well as other life functions in animals. Two experiments were conducted to assess the natural longitudinal changes that the VO undergo from birth through 150 kg body weight (BW). In Experiment 1, a total of 96 crossbred pigs were euthanized at birth (pre-suckle), d 1, 2, 3, 5, 7, 14, 21 (weaning), 22, 23, 24, 26, 28, 42, 49, and 63 of age. In Experiment 2, a total of 48 crossbred pigs were euthanized at 30, 50, 75, 100, 125, and 150 kg of BW. The absolute weight of VO, and the volume and length of the gastrointestinal tract (GIT) were measured. In both experiments, the absolute weight of VO, GIT length, and their volume increased (linear, quadratic, and/or cubic, P < 0.05) as BW and age increased. In Experiment 1, the relative weight of VO (liver, kidney, heart, and lung) decreased after initially increasing within the first week of life (linear, quadratic, and/or cubic, P < 0.05), whereas the relative weight of all VO decreased as BW increased in Experiment 2 (linear and/or quadratic, P < 0.05). The relative length of small intestine decreased and that of large intestine increased as age increased in Experiment 1 (linear and quadratic, P < 0.05), whereas the relative length of the small and large intestine in Experiment 2 were relatively constant at 80% and 20% of the total length of the intestine, respectively. As age and BW increased, the relative volume of the large intestine to the total volume of the GIT increased (linear and/or quadratic, P < 0.05), while the relative volume of the small intestine decreased (linear and/or quadratic, P < 0.05). In conclusion, results showed that both absolute and relative measurements (weight, volume, and length) of VO were dependent on the BW (age) of the pig.     

A field study on the effects of dietary monensin on milk production and milk composition in dairy cows

The objectives of this study were to quantify the effect of 16 ppm of dietary monensin on milk production and composition of dairy cows, and to investigate factors having a potential impact on this effect. Data were generated from a total of 3577 Holstein dairy cows (47 herds) in Quebec enrolled in a herd-level, randomized clinical trial investigating the effects of monensin supplementation. Milk production and composition data were collected from monthly dairy herd improvement (DHI) testing. Monensin increased milk production by 0.9 kg/cow/d in cows under 150 days in milk (DIM) (P < 0.05). Monensin decreased milk fat percentage by 0.18 percentage points during the whole lactation (P < 0.05). This decreasing effect was larger for component-fed cows (P < 0.05) and for cows being fed low levels of dietary physically effective particles (P < 0.05) when compared respectively to cows fed total mixed ration and cows fed high levels of dietary physically effective particles. The results of this study suggest that monensin influences milk production and milk composition of dairy cows, and that diet composition and feeding system influence those effects.     

Relationships among intramammary health,udder and teat characteristics,and productivity of extensively managed ewes

Mastitis is an economically important disease and its subclinical state is difficult to diagnose, which makes mitigation more challenging. The objectives of this study were to screen clinically healthy ewes in order to 1) identify cultivable microbial species in milk, 2) evaluate somatic cell count (SCC) thresholds associated with intramammary infection, and 3) estimate relationships between udder and teat morphometric traits, SCC, and ewe productivity. Milk was collected from two flocks in early (<5 d) and peak (30 to 45 d) lactation to quantify SCC (n = 530) and numerate cultivable microbial species by culture-based isolation followed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS; n = 243) identification. Within flock and lactation stage, 11% to 74% (mean = 36%) of samples were culture positive. More than 50 unique identifications were classified by MALDI-TOF MS analysis, and Bacillus licheniformis (18% to 27%), Micrococcus flavus (25%), Bacillus amyloliquefaciens (7% to 18%), and Staphylococcus epidermidis (26%) were among the most common within flock and across lactation stage. Optimum SCC thresholds to identify culture-positive samples ranged from 175 × 10³ to 1,675 × 10³ cells/mL. Ewe productivity was assessed as total 120-d adjusted litter weight (LW120) and analyzed within flock with breed, parity, year, and the linear covariate of log₁₀ SCC (LSCC) at early or peak lactation. Although dependent on lactation stage and year, each 1-unit increase in LSCC (e.g., an increase in SCC from 100 × 10³ to 1,000 × 10³ cells/mL) was predicted to decrease LW120 between 9.5 and 16.1 kg when significant. Udder and teat traits included udder circumference, teat length, teat placement, and degree of separation of the udder halves. Correlations between traits were generally low to moderate within and across lactation stage and most were not consistently predictive of ewe LSCC. Overall, the frequencies of bacteria-positive milk samples indicated that subclinical mastitis (SCM) is common in these flocks and can impact ewe productivity. Therefore, future research is warranted to investigate pathways and timing of microbial invasion, genomic regions associated with susceptibility, and husbandry to mitigate the impact of SCM in extensively managed ewes.     

Growth performance and gut health of Escherichia coli–challenged weaned pigs fed canola meal-containing diet

An experiment was conducted to evaluate the effects of including canola meal (CM) in diets for weaning pigs challenged with a F18 strain of Escherichia coli on growth performance and gut health. A total of 36 individually housed weaned pigs (initial body weight [BW] = 6.22 kg) were randomly allotted to one of the three diets (12 pigs/diet). The three diets were corn–soybean meal (SBM)-based basal diet (control diet) and the basal diet with 0.3% zinc oxide, 0.2% chlortetracycline, and 0.2% tiamulin (antibiotic diet) or with 20% CM diet. The diets were fed in two phases: Phase 1: days 0 to 7 and Phase 2: days 7 to 20. All pigs were given an oral dose of 2 × 10⁹ CFU of F18 strain of E. coli on day 7. Fecal score was assessed daily throughout the trial. Dietary antibiotics increased (P < 0.05) overall average daily gain (ADG) and average daily feed intake (ADFI) compared by 48% and 47%, respectively. Dietary CM increased (P < 0.05) overall ADG and ADFI by 22% and 23%, respectively; but the ADG and ADFI values for CM-containing diet did not reach those for the antibiotics-containing diet. Dietary antibiotics reduced (P < 0.05) fecal score; however, dietary CM unaffected fecal score. Dietary antibiotics decreased (P < 0.05) liver weight per unit live BW by 16% at day 20, whereas dietary CM did not affect liver weight per unit live BW (29.2 vs. 28.6). Also, dietary antibiotics increased (P < 0.05) serum triiodothyronine and tetraiodothyronine levels for day 14, whereas dietary CM did not affect the serum level of these hormones. Dietary antibiotics reduced (P < 0.05) the number white blood cells and neutrophils by 38% and 43% at day 20, respectively, whereas dietary CM tended to reduce (P = 0.09) the number white blood cells by 19% at day 20. The number white blood cells for CM diet tended to be greater (P < 0.10) than that for antibiotics diet. The dietary antibiotics decreased (P < 0.05) the concentration of individual volatile fatty acids and hence of total volatile fatty acid in cecum by 61% at day 20, whereas dietary CM decreased (P < 0.05) cecal butyric acid concentration by 61% and tended to reduce (P < 0.10) total volatile fatty acid concentration by 30% at day 20. In conclusion, the dietary inclusion of 20% CM improved ADG and tended to reduce white blood cell counts. Thus, inclusion of CM in antibiotics-free corn-SBM-based diets for weaned pigs that are challenged with F18 strain of E. coli can result in their improved performance partly through a reduction of the inflammatory response.     

Effects of dietary Forsythia suspensa extract supplementation to lactating sows and nursery pigs on post-weaning performance,antioxidant capacity,nutrient digestibility,immunoglobulins, and intestinal health

The aim of this study was to determine the effect of dietary Forsythia suspensa extract (FSE) supplementation to lactating sows and nursery pigs on post-weaning performance, antioxidant capacity, immunoglobulins, and intestinal health. Based on backfat, body weight (BW), and parity, 24 gestating sows (Landrace × Yorkshire) with average parity of 3.38 ± 0.61 and BW of 234 ± 6.81 kg were allotted into two dietary treatments (control vs. 100 mg/kg FSE) with 12 sows per treatment from day 107 of gestation to day 21 of lactation. After weaning, based on the initial BW and source litter, 192 nursery pigs (Duroc × [Landrace × Yorkshire], average BW of 6.98 ± 0.32 kg, weaned at day 21) were allotted into four dietary treatments with eight replicate pens per treatment, six pigs per pen for a 4-wk study. The treatments included the following: 1) CC (sows and their piglets both fed control diet); 2) CF (sows fed control diet and their piglets fed FSE diet [containing 100 mg/kg FSE]); 3) FC (sows fed FSE diet and their piglets fed control diet); and 4) FF (sows and their piglets both fed FSE diet). The MIXED procedures of SAS for a split-plot arrangement with sow diet as the whole plot and nursery diet as split plot were used to analyze the data. After weaning, piglets from FSE-fed sows had improved (P < 0.05) average daily gain and feed efficiency, and lower (P < 0.05) diarrhea rate in overall (day 1 to 28) compared with those from sows fed control diet. Piglets from FSE-fed sows also had higher (P < 0.05) contents of immunoglobulin G (IgG), growth hormone, superoxide dismutase (SOD), total antioxidant capacity in serum, villus height in ileum, and villus height to crypt depth ratio in jejunum, as well as lower (P < 0.05) content of malondialdehyde (MDA) in serum and crypt depth in ileum compared with those from sows fed control diet. Piglets fed FSE during nursery had increased (P < 0.05) concentrations of IgG, SOD, and catalase, and decreased (P < 0.05) MDA and tumor nuclear factor-α levels in serum compared with those fed control diet during nursery. Piglets from FC group had increased (P < 0.05) protein expression of occludin in jejunal mucosa and relative abundance of Lactobacillus on genus level in colon compared with those from CC group. In conclusion, for the performance and intestinal health, diets supplemented with FSE during lactation phase seemed more efficient to alleviate weaning stress than the nursery phase. In terms of the antioxidant status and immunoglobulins, FSE supplemented in both phases were efficient for nursery pigs.     

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.     

Effect of reduced energy density of close-up diets on dry matter intake,lactation performance and energy balance in multiparous Holstein cows

Energy intake prepartum is critically important to health, milk performance, and profitability of dairy cows. The objective of this study was to determine the effect of reduced energy density of close-up diets on dry matter intake (DMI), lactation performance and energy balance (EB) in multiparous Holstein cows which were housed in a free-stall barn and fed for ad libitum intake. Thirty-nine dry cows were blocked and assigned randomly to three groups fed a high energy density diet [HD, n = 13; 6.8 MJ of net energy for lactation (NE_L)/kg; 14.0% crude protein (CP) ], or a middle energy density diet (MD, n = 13; 6.2 MJ NE_L/kg; 14.0% CP), or a low energy density diet (LD, n = 13; 5.4 MJ NE_L/kg; 14.0% CP) from d 21 before expected day of calving. After parturition, all cows were fed the same lactation diet to d 70 in milk (DIM). The DMI and NE_L intake prepartum were decreased by the reduced energy density diets (P < 0.05). The LD group consumed 1.3 kg/d (DM) more diet compared with HD group in the last 24 h before calving. The milk yield and the postpartum DMI were increased by the reduced energy density diet prepartum (P < 0.05). The changes in BCS and BW prepartum and postpartum were not affected by prepartum diets. HD group had higher milk fat content and lower lactose content compared with LD group during the first 3 wk of lactation (P < 0.05). The energy consumption for HD, MD and LD groups were 149.8%, 126.2% and 101.1% of their calculated energy requirements prepartum (P < 0.05), and 72.7%, 73.1% and 75.2% during the first 4 wk postpartum, respectively. In conclusion, the low energy density prepartum diet was effective in controlling NE_L intake prepartum, and was beneficial in increasing DMI and milk yield, and alleviating negative EB postpartum.