Lactation efficiency as a result of body composition dynamics and feed intake in sows

Through genetic selection and improvement of environment, litter size of sows increases. Increased energy requirement during lactation, increases the risk of excessive mobilization from body stores, with detrimental effects on reproductive performance. Feed intake capacity tends to decrease due to selection towards leaner pigs with a lower feed conversion ratio. However, to facilitate sows to wean large litters extra feed intake, or even better, a higher feed efficiency during lactation would be favourable. The objective of the present study was to describe the dynamics of body composition of sows and piglets during lactation, and to relate these traits to a newly introduced trait called “lactation efficiency”. Energy metabolism of lactating sows was described, based on on-farm observations of weight and backfat of sows before parturition and at weaning, weight of piglets at birth and at weaning and feed intake of sows during lactation. “Lactation efficiency” was defined as energy efficiency of sows, and calculated for individual sows at two different farms. The average lactation efficiency was 68% and 65% for both farms; meaning that 68 and 65% of the metabolisable energy through feed intake or mobilization from body stores, above maintenance of the sow (input), was used for piglet growth and piglet maintenance (output). The association between lactation efficiency and other reproductive traits was studied by estimating the correlations within farms. Sows with a higher lactation efficiency showed lower feed intake (r = − 0.27 and r = − 0.35 for both farms respectively) and smaller fat losses (r = − 0.34 and r = − 0.29, respectively). The energy output of efficient sows was slightly higher (r = 0.23 and r = 0.30). The more efficient sows were the better mothers, as mortality of their piglets was lower (r = − 0.12 and r = − 0.16), piglet growth rate was higher (r = 0.16 and r = 0.23), and at weaning their litters were less variable (r = − 0.08; only available at one farm). Results were remarkably similar for the two farms, despite different feeding strategies. Extra input, by means of feed intake or mobilization from body stores generated extra output by means of litter weight at weaning. This experiment demonstrated that an accurate recording of energy metabolism and relevant reproduction traits with little intervention is possible on commercial farms.     

Gut ecology, feed digestion and performance in weaned piglets fed liquid diets

Gut environment and microflora, digestibility, and performance were studied in weaned piglets in Central Vietnam fed a dry control diet (CO), a naturally fermented liquid diet (FE), and a liquid diet with inclusion of rice distiller's residue (RDR). Digesta samples were collected at the start (day 0) and at the end of experiment (day 42). Diet FE had a lower pH than diet RDR, contained more organic acids, had the lowest counts of E. coli and total coliforms (P < 0.05), and the highest counts of lactic acid bacteria (LAB) (P < 0.05). Piglets fed diets FE and RDR had lower pH (P < 0.05), and higher concentrations of organic acids in the stomach, ileum and mid-colon (P < 0.05) than piglets fed diet CO. Counts of LAB in stomach and ileum were higher in animals fed diets FE and RDR than CO (P < 0.05), while the number of E. coli and total coliforms along the gastrointestinal tract was reduced. The ileal digestibility of crude protein and organic matter was improved in piglets fed diet RDR (P < 0.05) compared with piglets fed diet CO. Piglets fed diet RDR had a higher weight gain (P < 0.05) and a better feed utilization (P < 0.05) than piglets fed the other diets. The present findings support the contention that fermented diets and/or fermented feedstuffs can be used for dietary manipulation to improve gut health and animal performance.     

Effect of commercial diets quality on bio-economic performances of broilers in Benin

The objective of this study was to assess the quality of commercial poultry feeds in Benin. The performances of 396 unsexed broilers chickens Ross 308 fed with a control diet (R1) and five commercial diets (R2 to R6) were evaluated. Broilers fed commercial diets showed significantly low (P < 0.001) body weight gain (BWG) and economic feed efficiency (EFE) and significantly high (P < 0.001) mortality rate, feed conversion ratio and feed cost (FC). At 42 days of age, the body weight of broilers fed control diet was 1662 g versus 838 to 1041 g for broilers fed commercial diets. In R1 diet, overall FC was 388 Fcfa/kg BWG, and EFE was 2.7 Fcfa BWG/Fcfa feed. These values represented respectively 50 to 64% and 1.6 to 2.0 times the FC and the EFE recorded in commercial diets. A deficiency in crude protein and metabolisable energy, combined with high contents of crude fibre and total ash was found in some commercial diets. These results suggest the necessity to organize the market of poultry feed in Benin in the perspective to reduce the production cost by using more efficient and cheap commercial diets.     

Effect of supplementing urea-treated barley straw with lucerne or vetch hays on feed intake,digestibility and growth of Arsi Bale Sheep

The study was conducted at Sinana Agricultural Research Center, Ethiopia to assess the supplementation of graded levels of vetch (Vicia dasycarpa `lana’) and lucerne (Medicago sativa,’ Hunter river’) hay on feed intake, digestibility and body weight (BW) change of Arsi-Bale sheep fed urea treated barley straw (UTBS). A 7 day- digestibility and a 90 day- feed intake trials were conducted using 28 and 35 sheep, respectively. The experimental design was a randomized complete block design with seven dietary treatments that consisted of feeding UTBS (T1) as the control treatment, UTBS plus 150, 250 and 350 g dry matter (DM) per day of vetch for T2, T3, T4, respectively and UTBS plus 150, 250 and 350 g DM per day of lucerne for T5, T6 and T7, respectively. Intake of UTBS was not affected (P > 0.05) by inclusion of lucerne hay at 25–35% of daily DM intake. The supplements increased daily intake of total DM, organic matter (OM), neutral detergent fiber (NDF), acid detergent fiber (ADF) and metabolizable energy (ME) (P < 0.001) as well as apparent digestibility of DM, OM (P < 0.001), NDF (P < 0.01), ADF, crude protein (CP) (P < 0.05) and daily BW gain (P < 0.001). Supplementation with lucerne than vetch hay promoted higher (P < 0.001) CP and ME intakes and daily BW gain. Feeding with the UTBS without supplementation was enough to meet the maintenance requirements of the sheep and allow small BW gain. The results of the study showed that urea treatment of barley straw in conjunction with supplementation of lucerne or vetch hay could serve as a useful strategy in improving smallholder sheep production in the tropics.     

高效液相色谱法测定饲料中的黄曲霉毒素

目前对饲料中的黄曲霉毒素的检测一般采用酶联免疫法、薄层色谱法等半定量方法,笔者采用高效液相色谱法进行定性定量分析,其中黄曲霉毒素B1和黄曲霉毒素G1线性范围为5～50 μg/mL,黄曲霉毒素B2和黄曲霉毒素G2线性范围为1.5～15 μg/mL,平均回收率为80%～110%,RSD为5.00%～10.00%.结果表明采用HPLC法测定操作简便,定性准确,定量精确.     

饲用酸化剂研究进展

酸化剂被视为在畜禽饲料中的能有效替代抗生素的产品之一,近几年有关酸化剂的抗菌作用和调节营养生理功能的研究又取得许多新进展.通过搜索PubMed、CAB、Agricola、国家科技文献图书中心(NSTL)、国家知识基础设施(CNKI)数据库、万方数据库、维普数据库及相应的期刊,对国内外在仔猪日粮中添加饲用酸化剂研究应用概况作了较为全面综述.以期为饲用酸化剂在肉猪生产上的应用提供参考.     

Maize silage particle length modulates feeding patterns and milk composition in loose-housed lactating Holstein cows

This study analysed feeding patterns and feed selective consumption by loose-housed lactating dairy cows fed diets based on maize silage (MS) with different particle length (PL) to establish its effects on overall dry matter intake (DMI) and productive performance. Twelve multiparous Holstein cows were offered a total mixed ration (TMR) with three different PL of MS at harvesting (i.e., long, medium, and short). Results demonstrated greater numbers of day-time meals (i.e., 07:30–19:00 h) when PL was decreased from long to medium (P < 0.05). Night-time (i.e., 19:00–06:30 h) changes in the feeding pattern included an increased amount of feed per meal (P < 0.05) and a tendency to increase eating time per meal (P < 0.10) in cows fed the short-PL diet. Lowering the PL of MS also lowered the selective consumption against physically effective fibre larger than 1.18 mm (peNDF_> 1.18; P < 0.05) and in favour of fine particles (i.e., particles passing through 1.18 mm screen; P < 0.01). Decreasing PL of MS from long to medium and short increased daily DMI as well as the intake of energy and other nutrients contained in the diet including the amount of peNDF_> 1.18 (P < 0.01). The decrease in the PL of the diet also was associated with increased milk protein and lactose yield and milk urea nitrogen (P < 0.05). The actual milk yield and fat-corrected milk were not affected by the diet (P > 0.10). Although lowering of the PL tended to increase daily milk energy output (P < 0.10), the ratio between energy milk output and the energy intake was linearly decreased (P < 0.01), indicating a lower milk efficiency for the lower-PL diets. In conclusion, particle length of MS in a TMR has the potential to modulate circadian feeding patterns, selective consumption of the feed, daily DMI, and milk composition in high-producing dairy cows.     

Effect of magnesium sulphate and l-tryptophan and genotype on the feed intake, behaviour and meat quality of pigs

Sixty-nine entire male pigs with different halothane genotype (homozygous halothane positive — nn-, n = 36; and homozygous halothane negative — NN-, n = 33) were fed with a supplementation of magnesium sulphate (Mg) and/or l-tryptophan (Trp) in the diet for 5 days before slaughter. Animals were housed individually and were submitted to stressful ante mortem conditions (mixed in the lorry according to treatments and transported 1 h on rough roads). Individual feed intake was recorded during the 5-d treatment. At the abattoir, pig behaviour was assessed in the raceway to the stunning system and during the stunning period by exposure to CO₂. Muscle pH, colour, water holding capacity, texture and cathepsin activities were determined to assess meat quality. The number of pigs with an individual feed intake lower than 2 kg/day was significantly different among diets (P < 0.05; Control: 8.7%; Mg&Trp: 43.5%; Trp: 17.4%) and they were considered to have inadequate supplement intake. During the ante mortem period, 15.2% of pigs included in the experiment died, and this percentage decreased to 8.7% in those pigs with a feed intake > 2 kg/day, all of them from the stress-sensitive pigs (nn). In general, no differences were observed in the behaviour of pigs along the corridor leading to the stunning system and inside the CO₂ stunning system. During the stunning procedure, Trp diet showed shorter periods of muscular excitation than control and Mg&Trp diets. The combination of a stressful ante mortem treatment and Mg&Trp supplementation led to carcasses with high incidence of severe skin lesions. Different meat quality results were found when considering all pigs or considering only those with adequate supplement intake. In this later case, Trp increased pH₄₅ (6.15) vs Control diet (5.96) in the Longissimus thoracis (LT) muscle (P < 0.05) and pH at 24 h (Trp: 5.59 vs C: 5.47) led to a higher incidence of dark, firm and exudative (DFD) traits in SM muscle (P < 0.05). Genotype affected negatively all the meat quality traits. Seventy-five percent of LT and 60.0% of the SM muscles from nn pigs were classified as pale, soft and exudative (PSE), while none of the NN pigs showed these traits (P < 0.0001). No significant differences were found between genotypes on the incidence of DFD meat.Due to the negative effects observed in the Mg&Trp group in feed intake and carcass quality, the utilization of a mixture of magnesium sulphate and tryptophan is not recommended.     

混菌固态发酵饲料对生长育肥猪生产性能的影响

选用体质量为(20.68±0.82) kg左右的杜长大三元杂交仔猪120头进行试验,研究饲粮中添加混菌固态发酵饲料替代部分豆粕对生长育肥猪生长性能的影响.采用单因子完全随机设计,试验猪随机分成4个组,第一组为豆粕对照组;第二组为2.5%混菌固态发酵饲料替代组;第三组为5%混菌固态发酵饲料替代组;第四组为7.5%混菌固态发酵饲料替代组.试验猪体质量达到100 kg时屠宰,测定胴体性状和血清生化指标.与对照组相比较,各试验组的平均日采食量均差异不显著(P＞0.05),但饲料转化率均有所提高,并缩短了育肥时间,其中第三组达到显著水平(P＜0.05);与对照组相比,各试验组的平均日增体质量均有所增加,而第三组和第四组达到显著水平(P＜0.05);猪的腹泻率比对照组显著降低 (P＜0.05);饲喂混菌固态发酵饲料虽然不显著影响育肥猪的胴体质量、瘦肉率、肌内脂肪、滴水损失和pH值(P＞0.05),但可显著降低背膘厚度(P＜0.05)和提高其屠宰率(P＜0.05).试验各组血液各生化指标与对照组差异不显著(P＞0.05),但第三组甘油三酯含量显著降低(P＜0.05).这些研究结果揭示,在育肥猪日粮中添加混菌固态发酵饲料可提高饲料转化率和平均日增体质量,缩短育肥时间,一定程度上改善胴体品质和健康状况.     

半胱胺对生长后期银狐饲料消化能力的影响

通过饲养试验,研究了半胱胺对生长后期银狐体质量、采食量和饲料转化率的影响。选择健康生长期银狐224只组成试验群,其中200只为试验组,24只为对照组,采用二因子试验设计：一个因子为半胱胺的不同添加剂量,分别按每千克体质量添加10、40、70、100、130mg半胱胺;另一因子为半胱胺的不同添加间隔时间,分别为1、3、5、7、9d5个时间间隔。试验结果表明：每间隔5d,按每公斤体质量添加70mg半胱胺一次的饲养效果最好,比对照组银狐体质量提高25．35％、饲料转化率提高24．31％、采食量降低0．780％。