Effects of early pregnancy on postnatal maternal performance of mice

1977 ◽  
Vol 25 (1) ◽  
pp. 1-10 ◽  
Author(s):  
E. J. Eisen ◽  
W. R. Williams ◽  
J. F. Hayes

SUMMARYThe influences of age at first pregnancy and number of suckling young on maternal performance of mice were studied. Mean mating ages for early-pregnant and normal-pregnant females were 27 and 52 days respectively. Litter size from parturition (day 0) to day 12 of lactation was standardized to either 8 or 12 pups. The more rapid (P<0·01) growth rate and feed conversion efficiency of early-pregnant dams from mating to parturition continued from 0 to 12 days of lactation but occurred primarily in the first 3 days of lactation, so that there were no differences in body weight or feed intake from days 3 to 12 of lactation. There were no age at pregnancy effects on total mammary gland DNA, RNA or RNA/DNA ratio at day 12 of lactation or on individual progeny weights or feed conversion efficiency of litter growth from 3 to 12 days of lactation. Dams suckling eight young had a lower (P<0·01) feed intake, gain and feed conversion efficiency from 0 to 3 days of lactation. From 0 to 12 days of lactation, these dams were smaller, consumed less feed and their individual progeny weights were larger (P<0·01). Dams suckling eight pups had smaller (P<O01) mammary glands, less (P < 0·05) mammary gland DNA and a higher (P<0·05) RNA/DNA ratio. Interactions between pregnancy age and number suckling were not significant. Feed intake of the dam from 0 to 12 days of lactation was influenced more by litter weight gain (34%) than either dam weight gain (5%) or metabolic body size (6%). Maternal performance of mice, based on pup growth and mammary gland growth and function, was not affected by early pregnancy.

2008 ◽  
Vol 71 (9) ◽  
pp. 1797-1805 ◽  
Author(s):  
PAULA FAJARDO BERNÁRDEZ ◽  
CLARA FUCIÑOS GONZÁLEZ ◽  
JESÚSMÉNDEZ BATÁN ◽  
LORENZO PASTRANA CASTRO ◽  
NELSON PÉREZ GUERRA

The production of biomass and antibacterial extracellular products by Lactobacillus casei subsp. casei CECT 4043 was followed in both batch and in realkalized fed-batch cultures. Enhanced concentrations of biomass and antibacterial extracellular products were obtained with the use of the latter fermentation technique in comparison with the batch mode. The culture obtained by fed-batch fermentation was mixed with skim milk and used to prepare a probiotic feed for weaned piglets. To test the effect of the potentially probiotic culture of L. casei on body weight gain, feed intake, feed conversion efficiency, and on fecal coliform counts of piglets, two groups of animals received either feed supplemented with the probiotic preparation or avilamycin for 28 days. The control group was fed nonsupplemented feed. At the end of the administration period (day 28), the groups receiving probiotic and avilamycin exhibited the highest average body weight gain values, although the mean feed intake and feed conversion efficiency values were not different among the groups (P &gt; 0.05). For the entire experimental period (42 days), the control group exhibited the lowest feed intake value, the probiotic group exhibited the highest feed conversion efficiency value, and the antibiotic group exhibited the highest body weight gain (P &lt; 0.05). Interestingly, no significant difference in body weight gain was observed between the probiotic and the control groups by day 42 (P &gt; 0.05). Fecal coliform values decreased (although not significantly) by day 28 in the three groups. However, the mean counts returned to pretreatment levels by day 42 in all groups.


2014 ◽  
Vol 54 (9) ◽  
pp. 1428 ◽  
Author(s):  
S. T. Morris ◽  
F. Y. Chan ◽  
N. Lopez-Villalobos ◽  
P. R. Kenyon ◽  
D. J. Garrick ◽  
...  

Feed conversion efficiency is an important factor affecting profitability for cow-calf production systems. One method of characterising feed conversion efficiency is by calculating residual feed intake (RFI), the difference between measured and expected feed intakes. A high RFI value indicates low feed efficiency while a low RFI value indicates high feed efficiency. The present experiment used 49 Angus heifers sired by Angus bulls selected for high or low RFI. The progeny were bred on commercial farms and then transferred to Massey University at weaning at ~200 days of age. The heifers were weighed at ~30-day intervals and were mated at 15 months, calved at 2 years old and reared their calf to ~160 days of age. Each heifer had recorded its own liveweight gain (from its weaning to weaning of its first calf), herbage intake at 350 and 450 days of age using the n-alkane technique and maternal performance (calf production). These records were analysed to estimate the RFI of each heifer, and to determine differences in RFI between selection lines. There were no significant differences (P > 0.05) in liveweight or dry matter requirements between selection lines at Day 350, but differences were significant (P < 0.05) at Day 450 such that the high feed efficiency line were 24.6 kg heavier and required an extra 0.32 kg/head.day of herbage. There were no significant differences (P > 0.05) between the two lines in herbage intake or RFI measured at either Days 350 or 450. There were no differences (P > 0.05) in pregnancy rates, calf birth dates or birthweights, estimated 24-h milk production or calf weaning weights between the two lines. This experiment shows that beef cattle selected for low RFI have higher growth rates and heavier liveweights than cattle selected for high RFI; both lines had similar calf production at first breeding.


2015 ◽  
Vol 93 (12) ◽  
pp. 5849-5855 ◽  
Author(s):  
L. Cheng ◽  
C. M. Logan ◽  
R. J. Dewhurst ◽  
S. Hodge ◽  
H. Zhou ◽  
...  

1995 ◽  
Vol 43 (3) ◽  
pp. 287-296
Author(s):  
J.B. Schutte ◽  
A.J.M.A. Verstraten ◽  
N.P. Lenis ◽  
J. De Jong ◽  
J.T.M. Van Diepen

In 5 growth trials with a total of 420 pigs, tryptophan requirements from 20 to 40 kg liveweight were estimated. L-Tryptophan 0, 0.15, 0.30, 0.45 and 0.60 g/kg was added to a basal diet containing tapioca, barley and maize, with CP 162 g/kg and tryptophan 1.65 g/kg. The control diet was supplemented with lysine, methionine plus cystine, threonine, isoleucine, valine and histidine to assure that only tryptophan was limiting pig performance. Diets were freely given as pellets. Total tryptophan was about 2.10 g/kg for optimal weight gain and feed conversion efficiency in a diet containing NE 9.5 MJ/kg, corresponding with apparent ileally digestible tryptophan 1.77 g/kg.


2021 ◽  
Vol 33 (1) ◽  
pp. 9-15
Author(s):  
A. O. Fanimo ◽  
T. O. Oduronbi

Dried plantain (Musa paradisiaca) peels (DPP), either ripe or unripe (green), were given to Weaned rabbits to replace maize at O, 10, 20 and 30% levels in isonitrogenous (18% crude protein) diets for 56 days in a 2 x 4 factorial experiment. The 30% inclusion level of DPP depressed (P < 0.05) the final weight gain, daily weight gains, and feed conversion efficiency. Ripe or unripe DPP had no significant (P < 0.05) effect on the performance parameters except feed intake, which was improved (P < 0.05). The interaction between ripe or unripe DPP and inclusion levels significantly (P < 0.05) affected weight gain and feed conversion efficiency. Inclusion of DPP depressed (P < 0.05) dressing percentage and lumbar and limbs weights while the viscera weight was increased Ripeness the plantain peels had no significant effect (P < 0.05) on the carcass yield. There was also increase in profit margin expressed in terms of feed cost/ kg live weight gain with inclusion of plantain peel in the diet. The results of this study showed that ripeness slightly improved the nutritive value of DPP which can be included al 20% in weaned rabbits ' diet to replace maize.


1986 ◽  
Vol 66 (4) ◽  
pp. 1097-1105
Author(s):  
M. R. BEDFORD ◽  
J. D. SUMMERS

Male broilers were fed diets containing 14, 18 or 22% crude protein (CP) and 10.88, 12.13 or 13.39 MJ kg−1 metabolizable energy (ME) to 3 wk of age. For each level of CP and ME, three diets were formulated so that excess nitrogen arose mainly from nonessential amino acids (NEAA), essential amino acids (EAA) or both. The source of nitrogen excess had no effect on any of the parameters measured in birds fed the 18 and 22% CP diets. However, at 14% CP and over all energy levels, excess nitrogen in the form of EAA gave rise to superior results with regard to weight gain, feed conversion efficiency and carcass protein when compared to those diets where the excess nitrogen arose mainly from NEAA sources. Increasing dietary energy reduced the effect that source of nonessential nitrogen had on weight gain, feed conversion efficiency and carcass protein deposition at 14% CP. Key words: Amino acids, energy, protein, broilers


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