饲料用脂肪酶对哺乳母猪的繁殖性能及仔猪生产性能的影响

试验选择健康、体况良好、经产3～8胎次母猪30头,根据膘情进行随机分组。分为试验1组、试验2组、试验3组共3个处理组,每个处理5个重复,每个重复2头。试验1组为对照组,饲喂基础日粮;试验2组饲喂基础日粮+200g/t脂肪酶;试验3组饲喂基础日粮+300g/t脂肪酶。试验周期66d,全程采用盲测,研究哺乳母猪饲料中添加脂肪酶对仔猪断奶重、仔猪14d～21d增重、母猪采食量、母猪返情间隔的影响。结果表明:①在哺乳母猪料中添加不同浓度脂肪酶均可提高仔猪断奶重,差异显著(P<0.05);②可提高仔猪出生后14d～21d阶段增重,差异极显著(P<0.01);③对整个试验阶段母猪采食量无显著影响(P>0.05),300g/t组有提高采食量趋势;④可显著缩短母猪返情间隔(P<0.05)。结论:在哺乳母猪饲料中添加300g/t脂肪酶对母猪和仔猪各指标影响显著,经济效益良好。     

智能化饲喂模式对哺乳母猪采食量及生产性能的影响

试验旨在研究智能化饲喂模式对哺乳母猪采食量及生产性能的影响。选择胎次、膘情相近的健康母猪80头饲喂相同日粮,随机分为2组,每组40个重复,每个重复1头母猪。对照组采用人工投料饲喂,处理组采用智能化哺乳母猪饲喂器饲喂。试验期为产前7 d到仔猪28 d断奶,计35 d。检测哺乳母猪采食量及生产性能、哺乳仔猪生长性能。结果表明:与对照组相比,处理组哺乳母猪平均日采食量提高1.40 kg/d,哺乳母猪背膘损失减少1.52 mm,断奶至发情时间间隔减少1.1 d,哺乳期仔猪断奶个体重增加2.36 kg,日重增加244 g。结论 :采用智能化饲喂模式有利于提高哺乳期母猪的采食量,减少母猪背膘损失,减少断奶至发情时间间隔,改善母猪的泌乳性能,提高仔猪断奶重。     

不同甜菜粕添加水平对哺乳母猪生产性能的影响

试验研究不同甜菜粕添加水平对哺乳母猪生产和仔猪生长性能的影响,旨在为哺乳母猪饲料中甜菜粕的开发利用提供数据支持。选取3到5胎健康PIC母猪48头,随机分为3组,每组16个重复,每个重复1头,分别饲喂甜菜粕添加水平为0%,5%,10%的3种试验日粮。结果表明哺乳母猪日粮中添加甜菜粕可以显著提高哺乳母猪平均日采食量(P0.05),10%水平组哺乳母猪平均日采食量显著优于对照组。仔猪生长性能及母猪日均泌乳量、平均日采食量、发情间隔各处理组间差异均不显著(P0.05),但10%水平组可获得较好的仔猪平均断奶重、仔猪断奶窝重、窝增重、仔猪平均日增重、母猪日均泌乳量、母猪平均日采食量、母猪断奶发情间隔。研究表明,在哺乳母猪日粮中添加10%甜菜粕可提高哺乳母猪平均日采食量,有利于缩短哺乳母猪断奶发情间隔和提高断奶后母猪发情率。     

母猪分娩前体况与繁殖性能的关系

本研究为考察母猪分娩前体况与其繁殖性能的关系,通过跟踪头胎和二胎哺乳母猪哺乳期体况变化、分娩性能、断奶性能等数据得出如下结论:母猪分娩前体况与母猪分娩性能(初生重、窝重、产弱仔数等)无显著相关性;与仔猪断奶重无显著相关性,但母猪分娩前体况越肥,母猪哺乳期采食量越低,哺乳期体况损失越严重;哺乳期间母猪体况损失为3个体况刻度以内的发情率最高;分娩前体况11的母猪和断奶时体况刻度9的母猪断奶发情率最低,淘汰率最高。     

哺乳母猪配合饲料对比试验

挑选224头体况相近的临产母猪,分成2组,每组112头,母猪转入产房后分别开始饲喂试验1号料和试验2号料。结果发现,试验1组和试验2组在母猪胎次和产健仔数方面差异不显著,试验1组的健仔初生重显著高于试验2组,试验2组饲喂2号料25d后,与试验1组相比,断奶仔猪数提高0.7头,仔猪头均断奶重提高0.63kg,母猪断奶发情间隔缩短0.63d,哺乳母猪日均采食量提高0.44kg,母猪断奶7 d发情率提高15.19%,由此可知试验2号料的饲喂效果优于1号料。     

不同饲喂次数对哺乳母猪生产性能及营养物质消化率的影响

选择妊娠107 d,3～4胎龄的健康母猪36头,随机分为4个处理,每个处理3个重复,每个重复3头母猪.试验期28 d,饲喂相同的饲粮,但处理1每天饲喂2次(每天上午7:30和下午5:30),处理2每天饲喂3次(每天上午7:30,12:30和下午5:30),处理3每天饲喂4次(每天早上6:30,上午10:30和下午1:30,6:30),处理4每天饲喂5次(每天早上5:30,上午9:00,12:30和下午4:00,7:30),考察不同饲喂次数对哺乳母猪生产性能和营养物质消化率的影响.试验结果表明,增加饲喂次数可以使母猪尽快恢复体况,减少产后不食的发生;适当增加饲喂次数,可以提高哺乳母猪的采食量,改善营养物质的消化率,增加泌乳量从而提高仔猪断奶重,并缩短母猪断奶后发情间隔天数;哺乳母猪每天饲喂3～4次为宜.     

母猪妊娠期饲喂不同粗纤维水平饲粮对哺乳期采食量及泌乳性能的影响

为研究母猪妊娠期饲喂不同粗纤维水平饲粮对哺乳期采食量及泌乳性能等的影响,试验选择90头月龄和体况相近的新法系长白×大约克杂种1胎母猪,配种后根据体况等随机分为3组,从妊娠第2天开始,分别饲喂含粗纤维4%、6%和8%的饲粮,分娩后每组选择20头膘情、体况、月龄相近的健康1胎母猪,仔猪24h组内调整均匀,保证每头母猪带11头仔猪,饲喂相同的哺乳饲粮。结果表明:1)随着妊娠期饲粮粗纤维水平的提高,母猪哺乳期日采食量均有提高趋势,其中8%粗纤维组母猪哺乳期日采食量显著高于4%粗纤维组(P0.05);2)随着妊娠期饲粮粗纤维水平的提高,哺乳仔猪21日龄断奶重、日增重均有提高趋势,但差异不显著(P0.05);3)随着妊娠期饲粮粗纤维水平的提高,哺乳期仔猪死淘率有降低的趋势,但差异不显著(P0.05)。结果提示,妊娠期用高粗纤维饲粮能促进胃肠发育,有利于提高母猪哺乳期日采食量,进而影响到产房仔猪的日增重和死淘率。     

复合添加剂对经产母猪健康与繁殖性能影响的研究

为了研究复合添加剂对母猪健康与繁殖性能的影响,选择以往繁殖正常的第3~4胎次、体重和体况相近的长大二元经产母猪40头,随机分成试验组和对照组,每组20头,于母猪妊娠1个月开始试验。对照组母猪饲喂基础日粮,试验组母猪在基础饲粮中每天每头添加一剂复合添加剂,每月连续使用7天,至母猪断奶前结束,全程跟踪测评两组母猪的后续各项繁殖性能及其所哺乳仔猪的生长性能。研究结果表明:在母猪繁殖性能方面:与对照组相比,试验组母猪平均窝产活仔数提高1.45头(P<0.05),试验组母猪分娩的滞产率、早产率和哺乳期三联症发病率分别降低10、15和10个百分点,日泌乳力提高20.63%(P<0.05),初乳中IgG含量提高24.00%(P<0.05),初乳中各项营养成分也有改善的趋势(P>0.05);在哺乳仔猪生长性能方面:与对照组相比,试验组母猪所哺乳仔猪的初生窝重提高17.65%(P<0.01),21日龄断奶窝重提高19.21%(P<0.01),哺乳期仔猪平均日增重提高19.40%(P<0.01),试验组哺乳仔猪腹泻指数降低48.27%(P<0.01),其健康状况也得到明显改善;在断奶母猪再繁殖性能方面:与对照组相比,试验组断奶母猪体况评分提高21.57%(P<0.01),其在7天内和14天内的发情率分别提高10和15个百分点,情期受胎率提高7.77个百分点。试验证明,经产母猪饲喂复合添加剂不仅能有效改善母猪的产仔、泌乳性能及其所哺乳仔猪的健康状况和生长发育性能,而且能够有效提高断奶母猪发情配种受胎率等再繁殖性能。     

酵解和乳化饲料对哺乳母猪生产性能的影响

选取体况、胎次、体重和预产期相近的健康杜洛克哺乳母猪22头,随机分成2组,每组5个重复,4个重复2头母猪,1个重复3头母猪,即对照组、酵解和乳化饲料组,以探讨酵解和乳化饲料对哺乳母猪生产性能的影响。试验发现:哺乳母猪日粮在哺乳母猪饲料中直接添加酵解和乳化饲料饲喂22 d后,哺乳仔猪的结束总重、结束均重、净增总重和头均增重分别比对照组提高17.34%(P0.01)、2.36%、25.90%(P0.01)和9.90%(P0.05);哺乳仔猪的日增重比对照组提高5.68%(P0.05);哺乳仔猪26-27日龄死亡率比对照组降低80.61%(P0.01);哺乳母猪的日均采食量比对照组提高15.67%。结果表明:酵解和乳化饲料能够明显提高哺乳母猪的繁殖性能。     

不同营养水平对哺乳母猪及仔猪生产性能的影响研究

选用景宁县生源良种母猪养殖场体重、胎次相近，产仔数量在8头以上的长大经产母猪60头，分设3个不同营养水平的饲养试验。结果表明，哺乳期母猪营养水平高，采食量大，母猪哺乳期间失重小，体重大，仔猪增重率低；营养水平低，采食量小的哺乳母猪，哺乳期间失重大，发情间隔时间短，发情率低。     

Effect of lactation and rebreeding phase energy intake on primiparous and multiparous sow performance

Fifty-three primiparous sows were used to study the effects of a high-energy, fat-supplemented diet on sow lactation and rebreeding performance. Sows received either a low [Lo, 12.5 Mcal metabolizable energy (ME)/d] or high (Hi, 16.0 Mcal ME/d) energy sorghum-soybean diet during a 28-d lactation. At weaning, sows were randomly allotted, within lactation treatment, to a low (lo, 5.54 Mcal ME/d) or high (hi, 9.61 Mcal ME/d) energy sorghum-soybean diet until the day of first postweaning estrus. Primiparous sows fed Lo weaned larger (P less than .05) litters than sows fed Hi; however, average pig weight was not affected by lactation treatments. Primiparous sows fed Hi had more backfat at weaning (P less than .01) than Lo sows. In contrast, sow weight was not affected by dietary treatments. Neither lactation nor rebreeding treatments influenced days to rebreeding; however, an interaction (P less than .01) was observed. Mean days from weaning to rebreeding for Lolo, Lohi, Hilo and Hihi sows were 10.0, 7.6, 6.9 and 17.1, respectively. Forty sows were maintained on the same dietary treatments during their second parity. Sows receiving Lo during their second parity farrowed and weaned more (P less than .05) pigs than Hi sows. Multiparous sows fed Hi nursed heavier (P less than .05) pigs on d 21 of lactation and at weaning compared with Lo sows. Sows fed Hi were heavier (P less than .05) and had more (P less than .01) backfat at weaning of their second litter compared to Lo sows. Days to postweaning estrus were not affected by lactation or rebreeding diets. Mean length of the second parity rebreeding interval for Lolo, Lohi, Hilo and Hihi sows was 6.2, 10.2, 7.0 and 10.5 d, respectively. These results suggest that feeding levels during lactation of 12.5 Mcal ME/d or higher supported adequate rebreeding performance. Postweaning feeding levels did not influence days to first estrus. Feeding a high energy diet continuously throughout the lactation and rebreeding phases in primiparous sows may lengthen the postweaning interval to estrus.     

Nutrition for optimizing breeding herd performance.

Modern sows are younger and leaner at time of mating and probably have poorer appetites than sows of 10 to 15 years ago. Therefore, feeding strategies should aim to minimize weight loss and maintain a sow's body condition throughout her reproductive life. The efficiency with which gilts are introduced into the breeding herd is as important in economic terms as is the efficiency with which the sow returns to estrus after weaning. Gilts should be selected at 50 to 60 kg, and fed a 16% protein diet ad libitum until mated at their second estrus, when they weigh 115 to 120 kg and have 17 to 20 mm backfat. Flushing gilts before the onset of second or third estrus increases ovulation rate of restricted gilts to the levels achieved by gilts fed ad libitum. During gestation, maintenance represents 75 to 85% of total energy requirements. The aim should be to achieve 20 to 25 mm backfat at farrowing. Increased feed intake from day 2 to 3 after mating will not increase embryo mortality. Feeding an extra 1 kg feed/sow/day for the last 10 days of gestation increases piglet birth weight slightly and prevents a loss of 1.5 to 2.0 mm of sow backfat. Wherever possible, sows should be fed ad libitum from the day after farrowing until weaning. Reduced feed intake by lactating sows, for whatever reason, results in excessive weight and condition loss. Excessive weight loss in lactation causes extended remating intervals, a lower percentage of sows returning to estrus within 10 days of weaning, reduced pregnancy rate, and reduced embryo survival. Ovulation rate is not affected by level of feed intake in lactation. It has been suggested that sows will have minimum weaning-to-service intervals when they weigh 150 kg or more at weaning. It is likely that the sow must be anabolic for about 10 days before she will exhibit postweaning estrus. The decision when to rebreed is made some time prior to weaning and is mediated by a host of substrates, hormones, and neurotransmitters. Sows with a delayed return to estrus also have a lower pregnancy rate and smaller subsequent litters. If sows lose considerable weight or condition during lactation, a high level of feeding in the postweaning period will improve embryo survival.     

Effects of a novel carbohydrate and protein source on sow performance during lactation

Ninety-one primiparous and multiparous sows and their pigs were used to evaluate the effects of a novel carbohydrate- and protein-based feed ingredient (Nutri-Pal, NP) on sow and litter performance during lactation. Nutri-Pal is a feed supplement for sows that consists of a blend of milk chocolate, brewer's yeast, whey products, and glucooligosaccharides. The dietary treatments consisted of a corn-soybean meal control and a corn-soybean meal plus 5% NP fed from d 110 of gestation to weaning. The diets were formulated to be equal in total Lys and ME. Sows were allotted to treatment based on parity, body weight, and the date of d 110 of gestation. There were 46 and 45 sows per treatment over four farrowing groups. Litters were standardized to 10 pigs and weighed within 1 d of farrowing, and all sows weaned at least 8 pigs at an average age of 21 d. Sows were weighed on d 110 of gestation, d 1 postfarrowing, and at weaning. Sows were fed three times daily during lactation. Sows were checked twice daily after weaning for signs of estrus. The weaning weight of sows fed NP was increased (P < 0.10) compared with those fed the control diet. Sows fed the control diet tended (P = 0.11) to lose more weight per day from d 110 of gestation to weaning than the sows fed NP. Otherwise, sow response variables (sow weight on d 110 of gestation and d 1 postfarrowing, d 110 of gestation to d 1 postfarrowing and lactation weight change per day, d 110 of gestation to d 1 postfarrowing, lactation, and total feed intake, days to estrus, pigs born alive or dead, and litter and average pig birth weight) were not affected (P > 0.10) by diet. There were no effects (P > 0.10) of diet on litter performance response variables (pigs weaned, litter and average pig weaning weight and gain, and survival percent). The NP feed ingredient had minor effects on sow productivity, but it did not affect litter productivity indices.     

饲粮中添加中链脂肪酸甘油三酯对母猪繁殖性能、血清生化指标及初乳成分的影响

本试验旨在研究母猪妊娠后期和泌乳期饲粮中添加中链脂肪酸甘油三酯(MCT)对母猪繁殖性能、血清生化指标及初乳成分的影响。试验选取120头纯种大白妊娠母猪(3~5胎),根据母猪预产期相近,胎次、体况、历史繁殖成绩均衡分布的原则分为3组,每组40个重复,每个重复1头母猪。对照组饲喂基础饲粮(含3.17%豆油),油剂组以0.6%纯油剂MCT替换基础饲粮中0.6%的豆油(含2.57%豆油),粉剂组在基础饲粮中添加0.5%微胶囊粉剂MCT。试验从母猪妊娠第85天开始至仔猪断奶结束。结果表明:1)与对照组相比,油剂组和粉剂组母猪产程分别提高了17.58%(P0.05)和9.21%(P0.05),母猪泌乳期平均日采食量分别提高了5.92%和10.07%(P0.05),母猪断奶后7日发情率分别提高了6.52%和4.25%(P0.05);饲粮中添加MCT对母猪其他繁殖性能指标无显著影响(P0.05)。2)饲粮中添加MCT对母猪血清生化指标均无显著影响(P0.05)。3)与对照组相比,油剂组和粉剂组母猪初乳乳脂含量分别提高了18.09%和19.09%(P0.05),饲粮中添加MCT对母猪初乳成分均无显著影响(P0.10)。由此可见,在母猪妊娠后期及泌乳期饲粮中添加MCT未能改善母猪的生产性能、血清生化指标及初乳成分,但添加油剂型MCT可显著缩短母猪产程。     

Effect of dietary fibre on reproductive performance of sows during the first two parities

The aim of this study was to investigate the effect of dietary fibre on reproductive performance during the first two parities. Gilts were randomly allocated to receive three fibrous diets from days 1-90 of gestation, including low fibre [low fiber (LF), 10.8% neutral detergent fiber (NDF), n=132], middle fibre [middle fiber (MF), 15.8% NDF, n=132] and high fibre diet (HF, 20.8% NDF, n=135), until completion of the second parity. Response criteria included backfat measurements, litter size and pig weight at parturition and day 22 of lactation, weaning-oestrus-interval, oestrus rate, sow farrowing and culling rate, uniformity of newborns and relative organ weights. The results showed sows fed LF diet in parity 1 gained more backfat (p<0.05) during gestation but lost more (p<0.05) during lactation than sows fed HF diet. Furthermore, sows fed LF diet farrowed more pigs (+0.7-1.1 pigs, p<0.05) and pigs born alive (+1.0 pigs, p<0.05) relative to sows fed HF diet. Likewise, sows fed LF and MF diets had greater litter weights at parturition (both p=0.06) and day 22 after lactation (both p<0.05). In parity 2, yet, it was MF diet to increase both total pigs born and pigs born alive (+0.9-1.1 pigs, p<0.05) and litter weight (p=0.05) relative to other diets. After 22 d of lactation, intriguingly, sows fed HF diet had most pigs alive (p<0.01-0.07) and heavier litter weight (p=0.07 or 0.2). Feeding HF diet also increased internal organs weight of newborns (p<0.05). Collectively, feeding LF and MF diets had beneficial effects on litter weight at parturition and day 22 of lactation in parity 1, and feeding MF diet until parity 2 was able to improve litter size and weight at parturition, but this positive effect disappeared after 22 days of lactation, instead feeding HF diet showed the optimal litter performance.     

分娩后不同饲喂模式对泌乳母猪生产性能、乳成分和生理代谢的影响

本试验旨在研究母猪分娩后3种饲喂模式(产后不限饲、限饲3 d和限饲7 d后自由采食)对泌乳母猪生产性能、乳成分和生理代谢的影响。挑选遗传背景一致、体况和健康良好、分娩日期接近的3~6胎次丹系长×大母猪45头,分娩后根据体重、背膘厚度和胎次随机均分成3个组,每组15个重复,每个重复1头。3组母猪饲喂相同的泌乳饲粮,执行对应的饲喂模式:不限饲组(FR0组)分娩后立即自由采食;限饲3 d组(FR3组)分娩后前3 d逐步增加饲喂量,之后自由采食;限饲7 d组(FR7组)分娩后前7 d逐步增加饲喂量,之后自由采食。分娩后第22天仔猪断奶,试验结束。结果表明:1)FR0组和FR3组第1周和泌乳期母猪采食量以及哺乳期仔猪平均日增重(ADG)显著高于FR7组(P<0.05);FR0组泌乳期母猪背膘厚度和体重损失显著低于FR3组和FR7组(P<0.05);FR0组第1周和泌乳期母猪采食量显著高于FR3组(P<0.05),但哺乳期仔猪ADG的差异没有达到显著水平(P>0.05)。2)各组间乳成分没有显著差异(P>0.05)。3)与FR7组相比,FR0组和FR3组血浆中催乳素、胃饥饿素和瘦素含量显著增加(P<0.05),胰岛素和皮质醇含量显著降低(P<0.05);FR0组血浆尿素氮含量显著高于FR7组(P<0.05),与FR3组差异不显著(P>0.05);各组间血浆葡萄糖和甘油三酯含量没有显著差异(P>0.05)。由此可见,分娩后饲喂模式会影响泌乳母猪的采食量、背膘厚度和体重损失以及机体生理代谢状况。本试验条件下,现代高产瘦肉型母猪产后不限饲和缩短限饲天数(限饲3 d)都可以提高泌乳母猪的采食量和泌乳性能,其中不限饲是适宜的饲喂模式。     

补饲发酵芦笋下脚料对母猪粪便形态和乳汁质量的影响

本研究旨在探讨给妊娠后期和哺乳期母猪补饲发酵芦笋下脚料对母猪粪便形态和乳汁质量的影响。将15头膘情、胎次和预产期相近的妊娠母猪随机分配到Ⅰ组、Ⅱ组和Ⅲ组,每组5个重复,每个重复1头猪。Ⅰ组、Ⅱ组和Ⅲ组母猪每头每天分别补饲0、0.25和0.50 kg发酵芦笋下脚料。试验从母猪妊娠期的第85天开始到产后第21天结束。结果表明:1)给母猪补饲发酵芦笋下脚料能改善母猪的粪便形态。2)Ⅲ组母猪初乳中乳蛋白质、生长激素、胰岛素和免疫球蛋白G水平显著高于Ⅰ组(P0.05),肿瘤坏死因子-α水平显著低于Ⅰ组(P0.05)。3)Ⅱ组和Ⅲ组母猪第10天乳汁中总超氧化物歧化酶活性显著高于Ⅰ组(P0.05),而第21天乳汁中总超氧化物歧化酶活性则极显著高于Ⅰ组(P0.01);Ⅲ组母猪第21天乳汁中丙二醛、白细胞介素-1β、白细胞介素-6和肿瘤坏死因子-α水平分别显著低于Ⅰ组(P0.05)。由此得出,补饲发酵芦笋下脚料能减少妊娠后期和哺乳期母猪便秘的发生,并不同程度地改善母猪乳汁质量。     

影响断奶母猪发情率的原因及应对措施

本文旨在讨论影响断奶母猪发情率的原因及其解决措施,通过分析得出影响断奶母猪发情率的因素有营养、膘情、胎次、环境控制、霉菌毒素、光照、诱情、生殖系统感染、断奶日龄、卵巢囊肿以及一些疾病因素。根据这些原因对母猪发情的影响,讨论其应对措施。在仔猪断奶前后应做好母猪的饲养管理工作,根据母猪膘情合理饲喂,做好母猪生活环境的控制工作,提早预防母猪生殖道疾病。因此,合理控制母猪舍的光照时间,做好母猪的诱情、查情等工作,合理控制好断奶日龄,定期做好疾病的预防。为提高断奶母猪发情率,增强繁殖性能,提供理论依据。     

A review of factors influencing litter size in Irish sows

Many factors influence litter size. These include genetics, gilt management, lactation length, parity distribution, disease, stress and boar fertility. In the past 20 years, litter size in Irish sows has increased by only one pig. Born alive figures now average at 11.2 pigs per litter. In this regard, Ireland is falling behind our European competitors who have made significant advances over this time. Denmark, for example, has an average figure of 12.7 pigs born alive per litter and France an average of 12.5. The single area that could be improved immediately is sow feeding. It is important that sows are fed correctly throughout pregnancy. If over-fed during pregnancy, sows will have depressed appetite during lactation. If underfed in pregnancy, sows will be too thin at farrowing. The correct way to feed a pregnant sow is to match her feed allocation to her requirement for maintenance, body growth and growth of her developing foetuses. During lactation, sows should be given as much feed as they can eat to prevent excessive loss of body condition. Liquid-feed curves should be such that lactating sows are provided with a minimum mean daily feed supply of 6.2 kg. A small proportion of sows will eat more and this could be given as supplementary dry feed. Where dry feeding is practised in the farrowing house, it is difficult to hand-feed sows to match their appetite. Ideally ad libitum wet/dry feeders should be used. From weaning to service, sows should once again be fed ad libitum. If liquid feeding, this means giving at least 60 MJ DE (digestible energy) per day during this period. If dry feeding, at least 4 kg of lactation diet should be fed daily. The effort spent perfecting sow feeding management on units should yield high dividends in the form of increased pigs born alive per litter.     

Lactation feed disappearance and weaning to estrus interval for sows fed spray-dried plasma

Four experiments involving 265, 410, 894, and 554 sows (Exp. 1 to 4, respectively) were conducted to determine the effect of spray-dried plasma (SDP) at 0 or 0.25% (Exp. 1 and 2) and 0 or 0.50% (Exp. 3 and 4) in lactation diets on average daily feed disappearance (FD), sum of sow BW, fetal and placental loss from d 110 gestation to weaning (SWL), litter size at weaning, litter weight at weaning, and average days from weaning to first estrus (WEI). Experiments 1, 3, and 4 were conducted during summer months, and Exp. 2 was conducted during fall to winter months. Experiment 1 used only parity 1 and parity 2 sows and Exp. 4 used only mature (>2 parities) sows, whereas Exp. 2 and 3 used all parity groups. Sows fed SDP in Exp. 1 had increased (P < 0.01) FD and a tendency for reduced (P = 0.06) SWL and WEI (P = 0.06). Sows fed SDP in Exp. 2 had a tendency for increased (P = 0.09) sow BW at weaning and reduced (P = 0.09) SWL, whereas other variables were not different between diets. Parity 1 and 2 sows fed SDP in Exp. 3 had increased (P < 0.01) FD, but mature sows fed SDP had reduced (P = 0.02) FD. Pig survival and litter size at weaning for all parity groups was not different between diets. The WEI for parity 1 sows fed SDP was reduced (P = 0.02) and tended to be reduced (P = 0.10) for mature sows fed SDP, but was not different between diets for parity 2 sows. More parity 1 sows fed SDP were detected (P = 0.01) in estrus 4 to 6 d after weaning, and fewer were detected (P < 0.01) in estrus 6 d after weaning compared with control parity 1 sows. In Exp. 4, FD was reduced (P < 0.01) for mature sows fed SDP; however, litter weight and average pig BW at weaning was increased (P < 0.01) with more (P < 0.01) marketable pigs (pig BW > 3.6 kg) weaned per litter. Relatively low dietary levels of SDP (0.25 to 0.50%) fed to parity 1 sows farrowed during summer months increased lactation FD and reduced WEI. Mature sows fed SDP during summer months consumed less lactation feed without compromising WEI, but had an increased litter weight, average pig BW, and number of marketable pigs at weaning.