日粮中添加复合酵母对断奶仔猪生长性能的影响

选用出生日龄、体重相近的健康PIC断奶仔猪120头,随机分为对照组和试验组,每组6个重复,每个重复10头仔猪.对照组饲以基础日粮,试验组在基础日粮中添加0.3%的复合酵母,以研究复合酵母对断奶仔猪生长性能的影响.试验结果表明:复合酵母可显著地提高断奶仔猪的日均采食量(p<0.05),平均日增重(p<0.05),可以降低断奶仔猪的料肉比(p>0.05),同时复合酵母也有降低仔猪腹泻的趋势.     

妊娠期饲喂高纤维饲粮对母猪产仔性能及后代仔猪生长性能的影响

本试验旨在研究妊娠期饲喂高纤维饲粮对母猪产仔性能及后代仔猪生长性能的影响。选取40头经产二元母猪,按照背膘、胎次一致原则随机分为2组(每组20个重复,每个重复1头),分别为对照组和高纤维组。妊娠期对照组和高纤维组母猪分别饲喂基础饲粮(粗纤维水平为3.85%)和高纤维饲粮(粗纤维水平为5.02%),妊娠第107天进入产房后2组母猪统一饲喂哺乳期饲粮。2组母猪饲喂同种哺乳期饲粮,自由采食。试验期间记录母猪妊娠第49天、第84天、第110天以及哺乳第14天和断奶当天背膘厚,分娩时记录母猪产仔性能,哺乳期记录仔猪的生长性能。试验从母猪配种开始至分娩后21 d断奶结束。结果表明：1)与对照组相比,高纤维组母猪不同阶段背膘厚以及妊娠期背膘沉积量和哺乳期背膘损失量均无显著变化(P>0.05)。2)与对照组相比,高纤维组母猪窝产健仔数显著升高(P<0.05),初生窝重极显著升高(P<0.01),窝产活仔数有升高的趋势(P=0.058),窝产总仔数、窝产活仔数和初生个体重均无显著变化(P>0.05);高纤维组仔猪宫内发育迟缓率低于对照组;高纤维组母猪健仔率与对照组相比虽无显著变化...     

膳食纤维调节肠道菌群对母猪繁殖性能影响的研究进展

膳食纤维(DF)是母猪日粮中必不可少的营养素,能够提高母猪饱腹感,预防便秘,以及调节母猪肠道菌群。DF与母猪肠道菌群相互作用可以调节母猪繁殖性能、代谢功能,并影响仔猪的生长性能。文章综述了DF对母猪肠道菌群多样性的影响,以及DF与肠道菌群相互作用对母猪肠道菌群、代谢、排卵、泌乳和子代生产性能等方面影响的研究进展,旨在为DF在母猪日粮中的应用与研究提供一种新的策略。     

日粮添加铬对断奶仔猪生长性能的影响

本试验选择40头体重、胎次、日龄基本一致的健康仔猪,28日龄断奶,随机分成5组。对照组饲喂基础日粮,试验Ⅰ、Ⅱ、Ⅲ组将基础日粮中1.5%、1%、0.5%的鱼粉用同等重量的皮革蛋白粉代替,试验Ⅳ组喂基础日粮+0.02%酵母铬,正试期为35天。结果表明:①日粮添加0.02%酵母铬可显著提高断奶仔猪日增重(+20.08%,P<0.01);添加皮革蛋白粉各组都显著地提高了仔猪的日增重(0.5%组提高19.51%,P<0.01;1%组提高18.56%,P<0.05;1.5%组提高14.92%,P<0.05)。②日粮添加0.02%酵母铬显著增加了断奶仔猪平均日采食量(P<0.05),而添加皮革蛋白粉的各组则无显著影响(P>0.05)。③添加0.5%皮革蛋白粉饲料利用率显著提高(P<0.05),其余各组都有升高趋势,但差异不显著(P>0.05)。     

日粮中添加多肽菌素对妊娠母猪繁殖性能和新生仔猪生长性能的影响

试验旨在研究母猪日粮中添加多肽菌素对妊娠母猪繁殖性能和新生仔猪生长性能的影响。试验选取胎次、体况相近,预产期前45 d的母猪23头,随机分为2组,试验组12头,对照组11头。每头母猪单栏饲喂,作为一个重复。对照组饲喂基础日粮,试验组在基础日粮中添加2 g/kg多肽菌素。试验期69 d(妊娠期45 d,哺乳期24 d)。结果表明:(1)试验组母猪窝产仔总数比对照组高2.98%,窝产活仔数比对照组高4.98%,窝产健仔数比对照组高6.95%,健仔率比对照组高3.90%,但差异均不显著(P0.05)。(2)试验组仔猪初生窝重、初生个体重、断奶窝重、断奶个体重、平均窝增重及平均个体增重均比对照组显著提高(P0.05);(3)试验组仔猪初生窝重均匀度及断奶窝重均匀度分别比对照组提高32.23%和38.78%,差异极显著(P0.01)。说明妊娠母猪日粮添加2 g/kg多肽菌素可提高妊娠母猪繁殖性能和初生仔猪生长性能,提高生猪养殖的实际效益。     

日粮中添加啤酒酵母水解物对保育仔猪生长性能和免疫指标的影响

试验旨在研究日粮中添加啤酒酵母水解物对保育仔猪生长性能和免疫指标的影响。试验选用同一批次体重相近[(12.00±0.50)kg]的健康杜×长×大三元杂交仔猪96头,按体重和性别随机分为4个处理组,每个处理4个重复,每个重复6头猪(公、母各半)。分别饲喂以下4种日粮:(A)对照组(基础日粮);(B)基础日粮+2.5 kg/t啤酒酵母水解物;(C)基础日粮+5 kg/t啤酒酵母水解物;(D)基础日粮+10 kg/t啤酒酵母水解物。预饲期3 d,正饲期28 d。研究结果表明:在第一周、前两周、前三周的试验中,与A组相比,D组(添加10 kg/t)能显著的降低仔猪的料重比,分别降低6.00%、7.29%、16.24%(P0.05);从全期来看,与A组相比,D组(添加10 kg/t)能显著降低仔猪料重比,降低了5.40%(P0.05),对仔猪的平均日采食量和平均日增重无显著影响(P0.10)。与对照组相比,添加啤酒酵母水解物后能显著提高保育仔猪血清中免疫球蛋白IgG的含量(P0.05),增强仔猪的免疫力。     

日粮添加低聚糖对断奶仔猪生长性能的影响

该试验旨在研究日粮中添加低聚糖对断奶仔猪生长性能的影响。选取180头遗传背景和体重相近的28日龄断奶仔猪,采用单因子试验设计,按完全随机区组法分为3组,每组60头仔猪。各处理组仔猪分别饲喂基础日粮(A组)、基础日粮+1 5%低聚糖(B组)、基础日粮+3.0%低聚糖(C组)的试验日粮,分两阶段饲喂,前期16 d,后期17 d,共33 d。自试验开始至结束,每日观察猪只外表,如皮毛肤色、长势、整齐度等情况.记录仔猪呕吐、腹泻头数,并记录饲料消耗量,计算平均日采食量、平均日增重以及料重比等指标。结果表明:1)日粮中添加低聚糖可有效改善仔猪皮毛肤色和体型。与对照组相比,添加1.5%低聚糖组和添加3.0%低聚糖组的仔猪皮毛肤色更为光滑、红润,且体型更均匀壮实。2)日粮中添加低聚糖可有效改善仔猪生长性能。与对照组相比,添加1.5%和3.0%低聚糖均可提高仔猪的平均日采食量和平均日增重,降低料重比以及腹泻率,其中添加3.0%低聚糖可显著提高断奶仔猪的平均日采食量和平均日增重,显著降低料重比。由此表明,在该试验添加水平范围内,日粮添加低聚糖可改善断奶仔猪皮毛肤色和体型,提高断奶仔猪的生长性能。     

日粮添加复合益生菌对羔羊生长性能及免疫功能的影响

文章旨在研究日粮添加复合益生菌对哺乳羔羊生长性能、免疫功能指标的影响,试验将72只15日龄健康羔羊随机分为4组,每组18个重复（即18只,公母各9只）。各组随母哺乳并补饲颗粒料,对照组颗粒料中不含复合益生菌,试验1组、试验2组、试验3组颗粒料中分别添加5%、10%、15%复合益生菌发酵饲料,对比试验结束后各组羔羊生长性能和免疫指标的变化,试验结果显示：（1）在末重对比上,试验1、2组显著高于对照组（P＜0.05）,且两组日平均增重显著或极显著高于对照组（P＜0.05或P＜0.01）。（2）试验1、2组IgG含量显著高于对照组和试验3组（P＜0.05）|试验2组IgM含量极显著高于对照组（P＜0.01）。综上所述,颗粒日粮中添加10%复合益生菌能明显提高羔羊生长性能和免疫功能。[关键词]复合益生菌|羔羊|日粮|生长性能|免疫     

日粮添加复合甘草素对肉鸡生长性能和免疫功能的影响

文章旨在探究日粮添加复合甘草素对肉鸡生长性能和免疫功能的影响。试验将磷酸化甘草多糖和甘草提取物混合制成复合物,为复合甘草素（FGS）。试验选用180只1日龄未免疫健康白羽肉鸡,随机分为4组,每组45只,常规免疫新城疫疫苗。其中,3个试验组分别在基础饲粮中添加低、中、高3种剂量的复合甘草素,下文记为FGSL、FGSM、FGSH组,对照组采用常规日粮饲养。试验过程于第7、14、21、28、35天采样,检测体重、血清抗体效价、血清细胞因子含量、sIgA和IL-17含量的变化。结果表明,体重方面：在D7、D21,FGSM组的体重显著高于对照组（P＜0.05）,在D35,FGSL和FGSM组体重高于对照组,但无显著差异（P＞0.05）|血清抗体效价变化方面：在各时间段,试验组效价最高,D7各组差异不明显（P＞0.05）,但D21、D28、D35,试验组抗体效价均高于对照组（P＜0.05）|在血清细胞因子含量变化方面：在D14、D21、D28,FGSL、FGSM和FGSH组血清IFN-γ含量显著高于对照组（P＜0.05）,在D7、D21,FGSL、FGSM和FGSH组的血清IL-2含量高于对照组,但无显著差异（P＞0.05）,在D28、D35,FGSL、FGSM和FGSH组的血清IL-2含量显著高于对照组（P＜0.05）|在十二指肠洗液sIgA和IL-17含量变化方面：在D7、D14、D28和D35,FGSL、FGSM和FGSH组血清sIgA含量显著高于对照组（P＜0.05）,在D28、D35,FGSL、FGSM和FGSH组的血清IL-17含量显著高于对照组（P＜0.05）。结论：日粮添加复合甘草素能有效增强肉鸡生长性能和免疫功能。[关键词]复合甘草素|肉鸡|生长性能|免疫功能     

低能量日粮中添加非淀粉多糖酶对仔猪生长性能的影响

以杜×长×大杂交仔猪120头为研究对象,随机分成对照组Ⅰ(饲喂基础日粮)、对照组Ⅱ(基础日粮中减少292kJ/kg消化能)和试验组(基础日粮中减少292kJ/kg消化能,添加500g/t罗酶宝)3个处理组,研究低能量的玉米-豆粕型日粮中添加非淀粉多糖酶(木聚糖酶和β-葡聚糖酶)对仔猪生长性能和消化性能的影响。结果表明:与对照组Ⅱ相比,试验组仔猪的日增重提高6.53%(P<0.05),饲料转化率提高7.25%(P<0.05),粗蛋白质的表观消化率提高5.76%(P<0.05);与对照组Ⅰ相比,试验组仔猪在日增重、饲料转化率、营养物质表观消化率方面有一定的提高,但差异不显著(P>0.05),说明在日粮中添加500g/t罗酶宝与增加292kJ/kg消化能的效果相当。     

不同膳食纤维来源对断奶仔猪生长性能和养分消化率的影响

文章旨在评价饲粮中不同纤维来源对断奶仔猪生长性能和养分消化率的影响。试验选择84头体重接近的28日龄断奶仔猪,随机分为4组,分别饲喂对照组饲粮以及添加5%玉米纤维(CB)、小麦纤维(WB)、大豆纤维(SB)的饲粮,处理28d。试验结果:相比于对照组,CB、WB组料肉比(FCR)分别下降8.5%、7.9%(P<0.05);CB组仔猪总能量(GE)、有机物(OM)、干物质(DM)消化率分别降低2.1%、2.1%、2.9%(P<0.05),粗纤维(CF)、磷(P)消化率分别增加7.8%、29.3%(P<0.05);WB组仔猪GE、OM、DM消化率较对照组分别降低1.8%、3.9%、3.4%(P<0.05),CF、P消化率分别增加8.8%、19.3%(P<0.05);此外,SB组CF、OM、P消化率分别增加9.9%、5.1%、4.5%(P<0.05)。表明,饲粮中纤维显著影响仔猪生长,不同纤维源对仔猪生长性能及养分消化率的影响不同。     

日粮中添加茴香和大蒜素对母猪初乳抗氧化特性及仔猪早期生长性能的影响

通过在母猪妊娠后期和哺乳前期的日粮中添加茴香或大蒜素,来研究茴香和大蒜素对母猪初乳抗氧化特性及仔猪早期生长的影响。选取健康的经产母猪36头,将母猪随机地分为3组,其中对照组母猪21头,茴香组母猪7头,大蒜组母猪8头。从母猪的妊娠后期(产前第30天)至哺乳前期(产后第7天),日粮中分别添加300 mg/kg的茴香或大蒜素。结果显示:茴香组和大蒜素组母猪初乳中的T-SOD含量显著高于对照组(P<0.05),茴香组母猪初乳中的MDA含量显著低于对照组(P<0.05)。同时,茴香组母猪所产仔猪的出生重极显著高于对照组(P<0.01),7日龄时的体重也显著高于对照组(P<0.05)。试验表明,茴香能够增强母猪初乳的抗氧化性能,改善仔猪的早期生长性能。     

复合酶制剂对断奶仔猪生长性能和养分消化率的影响研究

试验选用体重和断奶日龄相近的"杜×长×大"三元杂交断奶仔猪(平均体重为9.08kg)60头以研究复合酶制剂对断奶仔猪生长性能的影响。试验猪按完全随机区组设计分为4个处理,每处理设3个重复,每个重复5头猪。对照组饲喂基础日粮(玉米/豆粕型),试验一、二、三组在基础日粮中分别添加0.05%、0.10%和0.15%的复合酶制剂。结果表明:日粮中添加0.05%、0.10%和0.15%的复合酶制剂,断奶仔猪的平均日增重分别提高8.82%(P0.05)、15.06%(P0.05)和11.53%(P0.05);料重比分别降低6.77%(P0.05)、10.53%(P0.05)和8.27%(P0.05);日粮中添加0.05%、0.10%和0.15%的复合酶制剂,仔猪饲料纤维和磷的消化率得到显著改善(P0.05),添加0.10%的复合酶制剂,仔猪饲料蛋白质消化率显著提高(P0.05)。因此,在断奶仔猪玉米-豆粕型日粮中,添加含酸性蛋白酶、中性蛋白酶、α-淀粉酶、糖化酶、β-葡聚糖酶、β-甘露聚糖酶及木聚糖酶的复合酶制剂,可促进饲料养分的消化,显著提高仔猪的日增重,降低料重比,减少腹泻的发生。复合酶制剂的添加量以0.10%效果最佳。     

日粮消化能与可消化赖氨酸水平对断奶仔猪生产性能的影响

本文旨在研究日粮不同消化能与可消化赖氨酸水平对断奶仔猪生产性能的影响.采用2×3因子设计,以消化能(3500 kcal/kg 与3400 kcal/kg)与可消化赖氨酸水平(1.10%、1.25%和1.40%)为两个主效应.选用288头23日龄断奶健康的杜X长X大三元杂交仔猪[初始体重(6.64±0.39)kg],公母各半,随机分为6个处理,每个处理6个重复,每个重复8头猪,试验期14 d.结果表明:在本试验条件下,与低消化能水平相比,高消化能组显著提高了仔猪日增重(4.6%)和饲料转化率(8.9%)(P＜0.01),降低了日采食量(5%)(P＜0.01).日粮消化能水平对腹泻率无显著影响(P＞0.05).随着日粮赖氨酸水平的提高.断奶仔猪日增重也相应提高(P=0.04).高赖氨酸比低赖氨酸组日增重提高12.4%,饲料转化率也提高5.3%(P＜0.01).日粮赖氨酸水平对日采食量和腹泻率影响并不显著.消化能与赖氨酸互作对试验猪日增重、日采食量、饲料转化率及腹泻率交互作用不明显.综合考虑,日粮消化能水平为3500 kcal/kg,可消化赖氨酸水平为1.25%时,断奶仔猪发挥最大的生长性能,日增重最大,饲料转化率最佳.     

Different dietary methionine to lysine ratios in the lactation diet:effects on the performance of sows and their offspring and methionine metabolism in lactating sows

Background: Over the last decade, the nutritional requirements of lactating modern genotype sows have increased. The current nutritional recommendations might be unable to meet the needs of increased litter size and milk production, and thus the nutritional requirements need to be re-evaluated. The current study was conducted to investigate the effects of dietary methionine to lysine(Met:Lys) ratios on the performance of and methionine metabolism in lactating sows.Results: During the 1~(st) week of lactation, piglets reared on sows in the 0.37 to 0.57 Met:Lys ratio groups grew faster than those reared on sows in the control group(0.27)(P 0.01). The 0.37-ratio group showed increased levels of GSHPx in plasma during lactation(P 0.01) and decreased concentrations of urea nitrogen in the plasma of sows(P 0.05).Compared with the 0.27-ratio group, the levels of T-AOC and GSH-Px in the plasma and homocysteine in the milk of lactating sows were significantly increased in sows in the 0.47-ratio group(P 0.01). In sows fed a 0.57-ratio diet, the levels of glutathione and taurine in the plasma and milk were improved significantly during lactation. However, the content of TBARS in the blood(P 0.05 at day 7 and P = 0.06 at weaning day) was increased(P 0.01). Moreover, there were linear increases in the levels of homocysteine in the blood and milk of sows during the lactation period(P 0.01)with increased dietary Met:Lys ratios in the lactation diet.Conclusions: The current study indicated that increasing the dietary Met:Lys ratio(0.37～0.57) in the lactation diet had no significant effect on the overall performance of sows or the colostrum and milk composition, but it increased piglet mean BW and piglet ADG during the first week of lactation. Increasing dietary methionine levels had no significant effect on antioxidant function in lactation sows, even though it increased levels of GSH and GSH-Px in the plasma of sows during lactation. However, the content of homocysteine in the plasma and milk increased during lactation due to a high level of dietary methionine.     

Effects of dietary supplementation of nucleotides from late gestation to lactation on the performance and oxidative stress status of sows and their offspring

Increased metabolic burdens in breeding sows, which are induced by elevated systemic oxidative stress, could increase the need for nucleotides to repair lymphocyte DNA damage; however, de novo synthesis of nucleotides may be insufficient to cover this increased need. This study investigated the effects of dietary nucleotides on milk composition, oxidative stress status, and the reproductive and lactational performance of sows. Forty multiparous sows were assigned to 2 dietary treatments (Control group, and 1 g/kg Nucleotides group) based on a randomized complete block design using their BW at 85 d of gestation as a block. Sows from 2 groups were fed a restricted diet during gestation and ad libitum during lactation. The experiment lasted from 85 d of gestation to 21 d of lactation. The reproductive performance of sows and the growth performance of suckling piglets were measured. Oxidative stress parameters and milk components were also analysed. Data were analyzed using contrasts in the MIXED procedure of SAS. Sows in the Nucleotides group consumed more feed during the first week (P < 0.01) and from 1 to 21 d (P < 0.05) of lactation than those in Control group. Correspondingly, the litter weight gain of piglets showed a tendency to increase from cross-fostering to 9 d (P = 0.09) and from cross-fostering to 20 d (P = 0.10) in the Nucleotides group relative to the Control group. Additionally, the Nucleotides group was higher (P < 0.01) than the Control group in the concentrations of uridine 5''monophosphate, guanosine 5''monophosphate, inosine 5''monophosphate, adenosine 5''monophosphate and total nucleotides in milk. Furthermore, the Nucleotides group was higher (P < 0.01) than the Control group in the serum levels of total antioxidant capacity (P < 0.01) for sows at 109 d of gestation and glutathione peroxidase for weaning piglets, but lower at the levels of thiobarbituric acid-reactive substances (P < 0.05) in serum of weaning piglets. This study indicated that maternal dietary nucleotides could promote piglet growth, probably due to the higher lactational feed intake and higher concentration of nucleotides in the milk of sows, and lower oxidative stress for both sows and piglets.     

Influence of phytase added to a vegetarian diet on bone metabolism in pregnant and lactating sows

The purpose of the study was to find out if the supplementation of phytase to a diet of gestating and lactating sows has any effects on performance and bone parameters of the animals. Forty primiparous gilts were assigned into four groups: group A with phytase [4.2 g total phosphorus (P)/kg (gestation) and 4.5 g total P/kg (lactation)], group B without phytase (with phytase supplementation in diet for rearing) and same P content as group A, group C without phytase and higher P contents [5.0 g total P/kg (gestation) and 5.5 g total P/kg (lactation)] and group D with the same diet as group B (no phytase during the rearing). A 6-phytase was used in this trial (750 FTU/kg diet). The four diets were fed during gestation and lactation. Faeces were collected to determine apparent digestibility of minerals. Blood samples were taken to analyse minerals and bone markers. After weaning the sows were slaughtered and the bones of one hind leg were prepared to measure bone mineral density (BMD) and bone mineral content (BMC) of the tibia. Bone ash and mineral content of the phalanx III were determined. Mean P concentrations in serum decreased during gestation and lactation. But there were no significant differences between the groups. Bone formation marker bone-specific alkaline phosphatase decreased at the beginning of lactation whereas bone resorption marker serum crosslaps increased. The BMD and BMC of the tibia were slightly higher in the groups fed higher concentrations of P and phytase. The ash and mineral contents of the phalanx were the highest for the group fed the highest concentration of P. The apparent digestibility of P increased during gestation mostly in group A (57%--> 69%). In conclusion, high P content and addition of phytase to the diet induced a slightly higher ash content of the bones. It is of high importance, that sows during gestation absorb enough P, to avoid lamenesses and sudden fractures. As not many studies with phytase have been performed during gestation and lactation in sows yet, we can recommend, that phytase as supplement can be used to keep P in the diet at a lower level without negative consequences for bone health.     

Photoperiod influences the immune status of multiparous pregnant sows and their piglets

Manipulation of photoperiod may provide a noninvasive, easily implemented, effective method to improve immune status and enhance the efficiency of production. The objective of this study was to evaluate the impact of manipulation of photoperiod on endocrine and immune responses of pregnant sows and their offspring. At d 83 of gestation, sows were moved to gestation stalls and kept on a photoperiod of 12 h of light:12 h of dark until d 90, when sows were assigned to a long day (LD; 16 h of light/d) or a short day (SD; 8 h of light/d) treatment. During farrowing and lactation, one-half of the sows remained on their initial photoperiod (LD:LD or SD:SD), whereas one-half were switched to the opposite treatment (LD:SD or SD:LD). Blood samples were collected from sows at d 0, 7, 14, and 21 posttreatment, 24-h postfarrowing, and the end of lactation (approximately d 21 postfarrowing). Piglets were bled at 7 and 21 d of age for immune measures. Relative to sows on LD, sows on SD had greater concanavalin A- (P = 0.003) and lipopolysaccharide- (P = 0.02) induced proliferative responses at d 7 but reduced responses at d 14. Compared with SD, sows on LD had a greater (P < 0.05) percentage of neutrophils and fewer (P < 0.05) lymphocytes at d 7, resulting in a greater (P = 0.05) neutrophil:lymphocyte ratio. Neutrophil phagocytosis was greater at d 21 in sows kept on LD. Cortisol concentrations tended to be greatest (P = 0.10) in sows on SD:SD at 24-h postfarrowing and throughout lactation. At 7 d of age, piglets on LD:SD had greater (P = 0.001) total white blood cells (WBC) and plasma cortisol (P = 0.001) relative to those on the other photoperiod treatments. Plasma immunoglobulin G was less (P = 0.001) in piglets from sows kept on SD:LD compared with the other photoperiod treatments. Piglets from sows kept on LD:LD tended to have lower total WBC (P = 0.08) at 21 d of age. Piglets from sows kept on SD:SD had greater concanavalin A- (P < 0.001) and lipopolysaccharide-induced (P < or = 0.10) proliferation responses and cortisol (P = 0.05). Phagocytosis was greater (P < 0.003) in piglets from sows that were kept on LD:LD. Cortisol (P = 0.02), WBC (P = 0.003), and immunoglobulin G (P = 0.001) were all influenced by gestational photoperiod treatment. These data indicate that photoperiod influences the immune status and endocrine response of piglets from dams that have been kept on a defined photoperiod. We conclude that photoperiod effects on piglets may be programmed in utero and can last throughout lactation.