黄鳝排粪活动的初步研究

室内研究了不同摄食方式下的黄鳝排粪活动以及摄食对黄鳝排粪量的影响.饥饿5d的黄鳝饱食2h,以后不再喂食,其排粪活动分5批完成,排粪时间为38-134h;饥饿5d的黄鳝按照0.5%体重投饵,则其排粪次数减少到2批,排粪时间为64-106h;1d饱食一次的黄鳝排粪活动分3批完成,排粪时间为28-92h;2d饱食一次的黄鳝排粪活动分4批完成,排粪时间为32-90h.换水和摄食极显著地刺激黄鳝排粪活动(p<0.01).每天的摄食量(X)和摄食后15h内的排粪量(Y)存在极显著的直线回归关系:Y=0.1502X 0.0017(p<0.01).这些研究结果将为人工养殖黄鳝的摄食管理和水质调控提供理论依据.     

长江江豚哺乳期母豚昼间行为和时间的分配

2006 年7 ～11 月,在铜陵淡水豚国家级自然保护区半自然水域采用随机取样法和焦点动物取样法对哺乳期长江江豚母豚昼间行为和时间分配进行了研究。结果表明,母豚用于摄食的时间占61. 2%;其次是母幼联系和移动,分别为18.8% 和7.6%;用于休息和社会行为的时间较少, 分别为6.1% 和5.2%; 其它行为的时间极少, 仅占1.1%; 摄食和母幼联系是其主要的行为。在活动规律方面, 其各种行为在强度、出现和持续的时间上存在较大差异。单因素方差分析表明,在哺乳期不同阶段长江江豚母豚的母幼联系差异极显著(P< 0.01), 摄食和社会行为存在显著差异(P< 0.05), 移动、休息和其它行为则不存在显著差异(P> 0.05); 而此期间在不同活动区域以上各种行为均存在极显著差异(P <0.01), 说明其对栖息环境具有选择性。      

圈养马麝幼仔哺乳期时间分配及影响因素

本研究于2017年7月17日至8月16日,在甘肃兴隆山马麝繁育场对圈养马麝(Moschus chrysogaster sifanicus)当年生仔麝进行哺乳期的行为取样,量化记录了摄食、卧息、刻板等10类行为,分析了仔麝哺乳期时间分配格局及与性别和年龄等因素的关系。结果表明,圈养马麝仔麝在哺乳期(1~3月龄)的卧息(39. 55%±4. 53%)及摄食(28. 03%±1. 58%)时间分配最多;仔麝在哺乳前期(1月龄)、中期(2月龄)及后期(3月龄)的卧息、摄食及刻板行为的展现时间逐渐增加,运动行为在中期达到峰值(4. 99%±0. 64%),母幼联系等其他行为逐渐下降;仔麝的刻板行为在哺乳中期开始发育,后期刻板行为(3. 33%±1. 83%)显著高于中期(1. 15%±0. 77%)(P <0. 05);仔麝摄食与排泄行为的分配时间呈正相关(r=0. 833,P=0. 010),母幼联系与社会行为呈正相关(r=0. 802,P=0. 017),环境探究与社会行为呈显著正相关(r=0. 970,P <0. 001);圈舍内有成年雄麝的仔麝的卧息时间(59. 50%±8. 17%)显著高于圈舍内缺失雄麝的仔麝(37. 82%±6. 12%)(P <0. 05),前者的母幼联系(1. 10%±0. 52%)也相对低于后者(3. 80%±1. 07%)(P>0. 05);仔麝性别对其行为时间分配的影响均不显著(P> 0. 05)。本研究表明,马麝的母幼关系属于典型"隐蔽者"类型,仔麝刻板行为的发育始于哺乳中期,其发育和表达强度随年龄递增而加强,同圈舍的成年雄麝对仔麝的行为和生长发育有负面效应。     

卧龙血雉繁殖期行为特征分析

1 995年 4～ 6月在四川卧龙自然保护区五一棚地区 ,采用无线电追踪技术结合野外行为观察 ,对血雉繁殖期行为特征进行了研究。结果表明 ,繁殖前期雄鸟在警戒行为的频次及持续时间上均显著地高于雌鸟 (T test,频次 ,t=-4 73 ,P <0 0 1 ;时间 ,t=-2 80 ,P <0 0 5 ) ;孵卵期 ,雄鸟在警戒行为的总持续时间上显著地高于雌鸟 (T test,t=-4 75 ,P <0 0 1 ) ,雌鸟在取食行为的总持续时间上显著地高于雄鸟 (T test,t=3 41 ,P <0 0 5 ) ;对雌雄个体行为同时进行观察的结果表明 ,雌鸟维持行为的时间与雄鸟警戒行为的时间显著正相关 (Y =49 68+0 2 693X ,r=0 71 79,P =0 0 0 2 6)。繁殖前期和孵卵期雄鸟的警戒行为可以提高雌鸟用于取食、理羽、沙浴的时间 ,而减少用于警戒的时间     

橘小实蝇对五个芒果品种的产卵偏好及清理落果防治效果研究

在2011年6—8月调查了橘小实蝇Bactrocera dorsalis(Hendel)对云南省元江县5个主要芒果品种的产卵为害情况,评估了清理落果对橘小实蝇的防治效果。结果表明树上果实和成熟落果受害率最高、产卵孔数量最多的品种是三年芒和红象牙芒;单位面积落果量(X)和监测雄虫数量(Y)显著相关(r1=0.884**,显著性P1=0.000),其回归方程为Y=-1.675+449.701X-204.933X2+27.046X3(R2=0.966,显著性水平P=0.000);累加虫量(X)与树上果实被害率(Y)的回归方程为Y=0.003X0.721(R2=0.953,P=0.000)。采拾落果可降低树上果实受害率约20%,减少田间虫口数44%左右。因此,清理落果对控制橘小实蝇田间种群数量、减少树上果实被害率有显著作用。     

塔里木河中下游地区不同地下水位对植被的影响

 根据近几年塔里木河中下游地区的大量监测结果,分析了不同地下水位对植被的影响。结果显示：1)在塔里木河中下游,地下水位与植被盖度和植物种类的回归模型分别可以表示为：Y=159.32e-0.314 8X,R2=0.819 3,　p<0.01;Y=9.113e-0.162 3X,R2=0.606 7, p<0.01。2)地下水位对植被的影响在很大程度上是通过改变土壤含水率来实现的,当地下水位在1～4 m时,其回归模型为：Y=64.898e-0.515X,R2=0.727,p<0.01;当地下水位在4～12 m时,Y=21.147e-0.178X,R2=0.658,p<0.01。当地下水位在3.5～4.0 m时,土壤含水率出现明显变化,因此认为3.5 m是塔里木河中下游地区草本植被生态恢复的最低水位。3)通过胡杨叶脯氨酸(Pro)和脱落酸(ABA)在不同水位条件下的含量变化,可以认为引起胡杨水分胁迫的地下水位出现在5.0 m。其后随着水位的降低,胡杨脱落酸的积累更加明显,地下水位与胡杨叶脱落酸含量可以表示为：Y=0.703 5e0.408X,R2=0.830 4, p<0.01。4)通过塔里木河下游输水后的植被调查,当地下水位出现明显升高后,植被的地表生态响应非常明显,乔灌草植被在水位升高至不同水位后均出现相应的变化,说明以上的分析是符合实际的。     

白头鹤孵卵后期的行为节律观察

作者于2003~2004年连续2年的4月末至5月初在黑龙江大沾河湿地自然保护区,对3对野生白头鹤(Grus monacha)的孵卵过程进行了定点观察,结果表明,白头鹤的卧巢行为(t=-4.92,P=0.00)和护巢行为(t=3.09,P=0.007)在雌、雄个体间存在极显著差异;不同孵卵阶段的卧巢行为(t=2.95,P<0.01)、护巢行为(t=4.29,P<0.01)和育雏行为(t=-6.79,P<0.01)表现出不同的节律性。天气状况是影响白头鹤孵卵期各行为的重要因素,晴天时的凉卵行为(t=1.55,P<0.01)和育雏行为(t=4.06,P>0.01)时间明显多于阴雨天。对雌、雄个体行为同时进行观察的结果表明,雌(雄)鹤卧巢行为的时间与雄(雌)鹤护巢行为的时间呈显著正相关(相关系数分别为R=0.94和R=0.86)。     

NUCB2/nesfatin-1对小鼠摄食行为的调控及机制

目的:探讨NUCB2/nesfatin-1对小鼠摄食行为的调控及机制。方法:利用侧脑室埋管,免疫组化染色等方法,探讨侧脑室和外周注射nesfatin-1对小鼠摄食行为的影响。结果:侧脑室注射不同剂量nesfatin-1(0.3μg,1μg,3μg),注药后4 h夜间进食量明显减少,且呈显著剂量依赖关系(t=2.61~4.78,P0.05~0.01),侧脑室注射3μg nesfatin-1,小鼠前3小时累积摄食量明显降低(t=8.69~10.73,P0.01),且持续降低12小时(t=2.64,P0.05),同时餐间间隔时间明显延长(t=2.66,P0.05),每分钟/1-4 h进食量明显降低(t=2.63,P0.05),且进食每克食物所用时间明显增加(t=3.02,P0.05)。在下丘脑弓状核,外侧区和背内侧核均有NUCB2/nesfatin-1免疫阳性神经元表达。皮下或腹腔注射nesfatin-1,小鼠进食量和进食行为均无显著改变(P0.05)。结论:中枢nesfatin-1可抑制小鼠摄食行为。     

鳖的形态学统计分析

利用生物统计学的方法对鳖的形态进行了分析 ,结果如下 :鳖的年龄 (Y)与体重 (X)的一元回归方程为 :Y =0 0 0 736 1X 0 4 534,年龄 (Y)与腹甲长 (X)的一元回归方程为 :Y =0 2 4 59X- 0 5480 ;雌雄鳖尾长差异显著 (P <0 0 5) ,雄鳖体重 (Y)对尾长 (X)的一元回归方程为 :Y =2 56 6 4X - 82 8 6 0 ;野生鳖体重 (Y)对背甲长 (X1)、体高 (X5)、头长 (X8)、眼径 (X9)、口裂 (X12 )等 13个形态学指标的最优多元回归方程为 :Y =880 51 6 79 16X1- 10 6 0 91X5 146 4 72X8- 82 96 6 4X9- 3142 0 9X12 ;控温条件下快速生长鳖体重 (Y)对腹甲宽 (X4 )、体高 (X5)、头发 (X8)、眼间距(X10 )、尾长 (X13)等 13个形态学指标的最优多元回归方程为 :Y =- 97 4 6 38 99X4 30 2 6X5-2 9 34X8 140 83X10 - 30 4 2X13.     

贵州草海越冬黑颈鹤飞出飞回夜栖地行为节律初步观察

野生动物行为节律常常是其对环境变化的一种行为适应。黑颈鹤(Grus nigricollis)越冬期会利用固定夜栖地,形成每天早晨飞出觅食,傍晚飞回夜栖的固定行为模式。为探索这一固定行为模式在越冬不同时期的变化及其影响因素,利用瞬时扫描法对草海湿地全部7个固定夜栖地的黑颈鹤飞出和飞回夜栖地准确时间及飞出之前和飞回之后在夜栖地的行为节律进行了观察。并且保证越冬前期(11月9日至12月31日)、中期(1月1日至2月21)和后期(2月22日至3月31日)3个阶段的调查时间分别不低于15 d。结果表明,越冬不同时期黑颈鹤飞出夜栖地时间差异极显著(F=23.38,P0.01),飞回夜栖地时间存在显著性差异(F=3.51,P0.05)。整个越冬期,黑颈鹤飞出夜栖地时间在中期延后,而到后期则更为提前,越冬前期、中期和后期飞出夜栖地的平均时间分别为7:34时、7:40时和7:13时;而飞回夜栖地时间逐渐延后,平均时间由前期的17:12时,至中期的17:40时和后期的18:15时。黑颈鹤飞出夜栖地之前的行为在越冬前期、中期和后期差异极显著(F=1 768.25,df=12,P0.01),飞回夜栖地之后的行为在前期、中期和后期差异亦极显著(F=793.98,df=12,P0.01)。越冬前期、中期和后期,黑颈鹤飞出夜栖地之前的行为与飞回夜栖地之后的行为均差异极显著(前期F=2 723.16,df=6,P0.01;中期F=1 979.48,df=6,P0.01;后期F=5 098.18,df=6,P0.01)。黑颈鹤在飞出夜栖地前的80 min内,其行为以保养(34.32%)和休息(32.38%)为主;而飞回夜栖地后的90 min内,以觅食(43.04%)和休息(23.68%)为主。飞出时刻与日出时刻呈显著强相关(r=0.832,n=48,P0.01),飞回时刻与日落时刻呈弱相关(r=0.353,n=47,P0.01)。日出时间与黑颈鹤飞出夜栖地的时间的差值(Y1)受飞离时的空气湿度(W)影响,二者成反比,Y1=0.469﹣0.625W,P0.05。黑颈鹤飞回夜栖地时刻与日落时刻的差值(Y2)受当天平均温度(T)的影响较为显著,Y2=1.231﹣0.107T,P0.05,当天平均温度越高黑颈鹤飞回夜栖地时间越早,温度越低,黑颈鹤飞回夜栖地的时间越晚。研究结果对于进一步探讨黑颈鹤完整夜栖行为及其对干扰的适应性具有重要意义。     

Effects of lactation, energetic deficit and remating interval on reproductive performance of primiparous rabbit does.

Female rabbits (n = 151) were assigned at their first parturition (day 0) to one of three treatment groups (A: non-lactating does and ad libitum feeding, R: non-lactating does and restricted feeding, L: lactating does and ad libitum feeding). Additional females (n = 18) were slaughtered at parturition. Experimental females were presented to the male on days 3 (A3, L3 and R3 groups, n = 25, 26 and 26, respectively) or 10 (A10, L10 and R10 groups, n = 25, 25 and 24, respectively) and were slaughtered on day 28 after parturition. Compared to does slaughtered on day 0, adipose tissues were lighter in L (-66%) and R (-32%) females while they were heavier in A females (+40%; P < 0.01). These results suggest that both L and R females were in energy deficit. Receptivity (80% vs. 98%) and conception rate (51% vs. 83%) were lower in L compared to A females (P < 0.01) regardless the day of male presentation. Ovulation rate (-14%) and conception rate (-26%) were lower in R3 than in A3 does (P < 0.05). Ovulation rate was 24% lower in the L10 than in the A10 group (P < 0.01). The uterine contents were lighter (-25%) in L and R than in A does (P < 0.001) regardless the day of male presentation. These results suggest that the energy deficit associated with milk production can partly explain the negative influence of lactation on reproductive performance.     

松嫩草地牛粪中大型节肢动物种类组成及种群动态变化

研究并分析了松嫩草地牛粪中大型节肢动物种类组成及动态变化.结果表明,在草地牛粪中共调查到大型节肢动物7目20科43种,以鞘翅目、膜翅目和双翅目为主.依其食性不同,分为粪食性型(8科19种)、腐食性型(4科4种)、植食性型(4科6种)、捕食性型(5科11种)、杂食性型(2科5种)、尸食性型(1科1种)和寄生性型(1科1种).根据鞘翅目金龟总科中营粪食性型生活的粪甲虫对牛粪利用方式的不同,分为外生粪甲虫(6种)、内生粪甲虫(5种)、远生粪甲虫(2种)和偷窃寄生粪甲虫(1种).除了双顶嗡蜣螂,牛粪中大型节肢动物数量与鲜牛粪重量具有显著正相关关系(p＜0.01).粪食性型种类数和个体数量随鲜牛粪堆置时间的延长而迅速减少,7d后消失,其个体总数量与鲜牛粪堆积时间呈显著的负相关关系(p＜0.01),而与牛粪含水量呈显著正相关关系(p＜0.01),各种大型节肢动物因其食性不同在鲜牛粪中占据不同的生态位.鲜牛粪中大型节肢动物以粪食性型占绝对优势,而干牛粪中则以捕食性型和杂食性型为主.牛粪中大型节肢动物种群季节动态变化受温度、降水量与牛粪含水量影响,鲜牛粪中大型节肢动物优势种为直蜉金龟(69.25%)和肖秋家蝇与东方角蝇幼虫(25.12%).4、5、6月份和9月份,优势种为直蜉金龟,7月和8月份,优势种为蝇幼虫.     

Influence of ammonium chloride feeding time and light intensity on the cultivation of Spirulina (Arthrospira) platensis

This study dealt with the influence of both the feeding time and light intensity on the fed-batch culture of the cyanobacterium Spirulina (Arthrospira) platensis using ammonium chloride as a nitrogen source. For this purpose, a 2(2) plus star central composite experimental design combined with response surface methodology was employed, and the maximum cell concentration (X(m)), the cell productivity (P(X)), and the yield of biomass on nitrogen (Y(X/N)) were selected as the response variables. The optimum values of X(m) (1,833 mg L(-1)) and Y(X/N) (5.9 g g(-1)) estimated by the model at light intensity of 13 klux and feeding time of 17.2 days were very close to those obtained experimentally under these conditions (X(m) = 1,771 +/- 41 mg L(-1); Y(X/N) = 5.7 +/- 0.17 g g(-1)). The cell productivity was a decreasing function of the ammonium chloride feeding time and a quadratic function of the light intensity. The protein and lipid contents of dry biomass collected at the end of cultivations were shown to decrease with increasing light intensity.     

Lactation weight loss influences subsequent reproductive performance of sows

In order to examine the effect of different lactation weight losses of sows of different parity on subsequent reproductive performance, the present trial was performed in German (n = 4) and Slowakian (n = 11) indoor pig breeding units (n = 1677 sows evaluated). Weaning-to-service-intervals, farrowing rates and total-born litter sizes in sows with different lactation weight losses were compared. Sows were categorized according to lactation weight losses of <5%, 5-10%, 11-15%, 16-20%, >20%. Lactation weight losses exerted a quadratic effect (P < 0.01) on weaning-to-service-intervals. When analyzed across parity categories, with parity category included as a fixed effect, the weaning-to-service-intervals appeared to be minimized at lactation weight losses of <5%. Weaning-to-service-intervals increased (P < 0.05) when lactation weight losses increased above 5% for parity 1 sows, but not until lactation weight losses exceeded 10% for animals of parity 2 and more. There was a parity effect observed at lactation weight losses of <10%, P < 0.05, but the difference was not significant any more at lactation weight losses of >10%. Lactation weight losses >10% had a negative (P < 0.05) effect on subsequent farrowing rates to first service. The difference was higher (P < 0.01) in sows with lactation weight losses >20%. Lactation weight losses exerted a negative (P < 0.001) effect on total-born litter sizes in parity 1 versus parity >5 and parity 1 versus parity 2-5 sows at lactation weight losses of >10%. CONCLUSION: As weight loss of sows during lactation increases subsequent reproduction performance decreases.     

竹巴笼矮岩羊昼间行为节律和时间分配

2008年11月中旬至2009年1月中旬和2009年3月至8月,采用瞬时扫描取样法和目标取样法在竹巴笼自然保护区对矮岩羊的昼间行为节律和时间分配进行了研究,结果表明:矮岩羊的昼间行为活动有明显的节律性,活动高峰出现的时间与矮岩羊昼间取食高峰时间基本一致。取食和卧息是最主要的行为方式,分别占总观察频次的53.83%和27.76%,频次较少的是站立和移动,分别占总观察频次的9.93%和8.24%,其它行为所占频次最少,只有0.24%,昼间2个取食高峰(9:00-11:00, 17:00-19:00)和1个卧息高峰(11:00-16:00),呈现出取食-休息-取食的规律。Kruskal-Wallis H 检验表明,季节因素对矮岩羊取食(P <0.05)、卧息(P <0.05)和其它行为(P <0.05)所占时间影响显著,而对移动(P >0.05)和站立(P >0.05)行为影响不显著。各年龄段之间其它行为所占的时间比例差异显著(P<0.05),而取食(P>0.05)、移动(P>0.05)、卧息(P>0.05)和站立(P>0.05)所占时间比例差异不显著;对比分析不同性别矮岩羊昼间行为时间分配差异,雌性的取食、移动和卧息的时间略高于雄性,而站立和其他行为时间低于雄性;Mann-Whitney U 检验对不同性别矮岩羊昼间的各种行为差异进行分析表明:性别因素对矮岩羊昼间时间分配和行为节律产生一定程度的影响,但差异不显著(P>0.05)。     

The duration of ovulation in pigs, studied by transrectal ultrasonography, is not related to early embryonic diversity

The duration of ovulation in pigs was studied by transrectal ultrasonography. The number of preovulatory follicles was counted on both ovaries at 30-minute intervals from 36 hours after the onset of estrus (Group A: naturally ovulating sows that were group-housed and were inseminated and caged during scanning) or 40 hours after treatment with human chorionic gonadotropin (hCG) (Group B: tethered sows that had been induced to ovulate but were not inseminated). The duration of ovulation was (mean+/-SD) 1.8+/-0.6 hours (range 0.75 to 3.25) in Group A (n=13) and 4.6+/-1.7 hours (range 2.0 to 7.0) in Group B (n=8). The difference was significant (P<0.01). In Group A and B sows, respectively, the course of ovulation, expressed as the relation between the relative follicle count (percentage of the maximum follicle count; Y) and the time (percentage of the duration of ovulation; X) was: Y = 104.3( *)e(-0.023( *)X) (R(2)=0.95) and Y = 98.9( *)e(-0.018( *)X) (R(2)=0.92). The onset of ovulation occurred at approximately two-thirds of the duration of the estrus (Group A: 67+/-6%; Group B: 60+/-10%). Group A sows were artificially inseminated and were slaughtered at 98+/-8 hours (range 77 to 110) after ovulation. The difference between the maximum follicle count and the corpora lutea count was zero or only 1 in 81% (21 26 ) of the ovaries. Embryonic diversity (within-litter SD of the number of nuclei or of the number of cell cycles) was not related to the duration of ovulation, neither at the level of ovary nor of sow (P>0.05). In conclusion, transrectal ultrasonography was found to be an appropriate nonsurgical method of studying the duration of ovulation in pigs. The duration of ovulation varied both between sows and between groups of sows, and was not related to early embryonic diversity.     

Differential expression of hypothalamic neuropeptides in the early phase of diet-induced obesity in mice

Exposure to high-fat diets for prolonged periods results in positive energy balance and obesity, but little is known about the initial physiological and neuroendocrine response of obesity-susceptible strains to high-fat feeding. To assess responses of C57BL/6J mice to high- and low-fat diets, we quantitated the hypothalamic expression of neuropeptides implicated in weight regulation and neuroendocrine function over a 2-wk period. Exposure to high-fat diet increased food consumption over a 2-day period during which leptin levels were increased when assessed by a frequent sampling protocol [area under the curve (AUC): 134.6 +/- 10.3 vs. 100 +/- 12.3, P = 0.03 during first day and 126.5 +/- 8.2 vs. 100 +/- 5.2, P = 0.02 during second day]. During this period, hypothalamic expression of neuropeptide Y (NPY) and agouti-related protein (AgRP) decreased by approximately 30 and 50%, respectively (P < 0.001). After 1 wk, both caloric intake and hypothalamic expression of NPY and AgRP returned toward baseline. After 2 wk, cumulative caloric intake was again higher in the high-fat group, and now proopiomelanocortin (POMC) was elevated by 76% (P = 0.01). This study demonstrates that high-fat feeding induces hyperphagia, hyperleptinemia, and transient suppression of orexigenic neuropeptides during the first 2 days of diet. The subsequent induction of POMC may be a second defense against obesity. Attempts to understand the hypothalamic response to high-fat feeding must examine the changes as they develop over time.     

Influence of feed intake during pregnancy and lactation on fat body reserve mobilisation, plasma leptin and reproductive function of primiparous lactating sows.

From day 23 of pregnancy, 24 gilts received either a medium (M, n = 16) or a high (H, n = 8) level of feeding calculated to meet 115% or 190% of energy for maintenance, respectively. During lactation, all H sows were fed ad libitum (H-AL) whereas M sows were fed either ad libitum (M-AL, n = 8) or were restricted (M-RE, n = 8) to the amount of feed ingested by H-AL sows. Increased feed intake during pregnancy increased live weight, backfat thickness, and estimated body lipid and protein on days 4 and 25 of lactation (P < 0.05). It also resulted in lower feed intake and higher lipid mobilisation during lactation (P < 0.05) without a detrimental influence on milk production. Activities of malic enzyme and glucose-6-phosphate dehydrogenase from neck fat samples were higher in H than M sows on day 4 (P < 0.05). They decreased during lactation in H sows (P < 0.05). Mean diameter of adipocytes decreased during lactation in the 3 groups (P < 0.05) but did not differ between groups on days 4 and 25. Plasma leptin on days 4, 11, 18 and 25 was higher in H than in M sows (P < 0.05) but was not influenced by lactational feed intake. Neither measured characteristics of gonadotrophin secretion on day 22, nor of ovarian activity on day 26, were significantly influenced by the level of feeding during pregnancy or lactation.