NEURAL FACTORS IN THE MAINTENANCE OF LACTATION IN THE RAT

1967 ◽  
Vol 38 (1) ◽  
pp. 51-59 ◽  
Author(s):  
J. A. EDWARDSON ◽  
J. T. EAYRS
Keyword(s):  
Litter Size ◽  
Milk Yield ◽  
Quantitative Relationship ◽  
Mammary Tissue ◽  
Single Pair ◽  
Endocrine Response ◽  
Peripheral Innervation ◽  
Lactational Performance ◽  
Neural Factors

SUMMARY The role of the peripheral innervation of mammary tissue in the maintenance of lactation has been investigated by the procedure of selective thelectomy combined with denervation of the posterior thoracic nipples. When suckling is restricted to a single pair of nipples bilateral transection of the three adjacent nerves supplying a nipple arrests lactation completely; partial denervation is associated with a reduced level of lactational performance which is directly related to the concentration of the residual innervation. Increase in litter size is associated with an overall increase in milk-yield up to a limit beyond which the addition of further young to the litter is without effect. It is inferred that there is a quantitative relationship between the neural stimulus of suckling and the endocrine response of the hypothalamopituitary system.

Lactational performance of Giza White rabbits and its relation with pre-weaning litter traits

1994 ◽  
Vol 59 (1) ◽  
pp. 141-145 ◽  
Author(s):  
M. H. Khalil
Keyword(s):  
Milk Production ◽  
Litter Size ◽  
Milk Yield ◽  
Mixed Models ◽  
The Other ◽  
Curvilinear Relationship ◽  
Litter Weight ◽  
Lactation Stage ◽  
Litter Traits ◽  
Lactational Performance

AbstractAn experiment was carried out in Egypt using Giza White rabbits to investigate their lactational performance and to estimate the repeatabilities of milk yield and other litter traits. Data on 325 litters from 115 does fathered by 40 sires were used. Lactation traits involved milk yields during the first 7 days, 21 days and 35 days. Litter traits included litter size and weight at birth, number born alive, litter weight and gain at 21 days, litter size and weight at weaning and pre-weaning litter gain. Linear mixed models were used for analysing such data.Phenotypic variation in milk yield was relatively high during the first 7 days, and decreased thereafter with advance of lactation stage. Year-season effects were significant for most litter traits, while month of kindling affected litter weight and gain at 21 days and milk yield during the first 7 days (P < 0·05 or P < 0·001). Litters kindled during winter had the highest milk yield compared with litters kindled in the other seasons. Milk production, litter size and weight and litter gain had curvilinear relationship with parity (P < 0·05 or P < 0·001). Sire of doe had no significant effects on litter traits studied. Repeatabilities of all traits were low and ranged from 0·001 to 0·134. Litter size and weight at birth were residually correlated with milk yield. Litter weight and gain at 21 days were significantly correlated with the lactational performance of the doe (P < 0·001).

Is mammary output capacity limiting to lactational performance in mice?

1996 ◽  
Vol 199 (2) ◽  
pp. 337-349 ◽  
Author(s):  
K A Hammond ◽  
K C Lloyd ◽  
J Diamond
Keyword(s):  
Food Intake ◽  
Litter Size ◽  
Mammary Glands ◽  
High Food ◽  
Uptake Capacity ◽  
Start Up ◽  
Lactational Performance ◽  
Teat Number ◽  
Size Controlled ◽  
Stimulation Of

Using lactation in mice as a model, we sought to determine whether ceilings on sustained energy expenditure reside in the capacities of energy-acquiring and input organs (such as the intestine) or of energy-expending and output organs (such as the mammary glands). To distinguish between these possibilities experimentally, we surgically varied the teat number of lactating mother mice while simultaneously varying their litter size. The energy burden on each teat (i.e. the pup/teat ratio) could thus be varied independently of the energy burden (i.e. litter size) on the mother herself or on her intestine. At each teat number, pup mass proved to be maximal at intermediate litter sizes. At a given pup/teat ratio, mothers with five teats weaned pups no larger than the pups of normal (10-teat) mothers, even though the total energy burden on the former mothers was only half as large. Mothers with only two teats could not wean any pups. Litter size controlled maternal food intake, which in turn controlled intestinal mass and nutrient uptake capacity. Disproportionately high food intake for the smallest litters appears to reflect capital start-up costs of lactation. Pup mass is evidently limited by inadequate suckling stimulation of mammary glands.

Lactational performance, nursing and maternal behavior of Upton-Meishan and Large White sows

2001 ◽  
Vol 81 (4) ◽  
pp. 487-493 ◽  
Author(s):  
C. Farmer ◽  
M. F. Palin ◽  
M. T. Sorensen ◽  
S. Robert
Keyword(s):  
Growth Rate ◽  
Milk Yield ◽  
Milk Sample ◽  
Maternal Behavior ◽  
Feed Intake ◽  
Energy Content ◽  
Large White ◽  
Lactational Performance ◽  
Daily Milk Yield ◽  
Daily Milk

The growth of litters from 19 Upton-Meishan (UM) and 16 Large White (LW) sows was recorded from birth to weaning (25 d of age). Water and feed intake of sows were recorded. Suckling behavior was studied on days 5 and 20 of lactation. Milk yield was measured on day 22 and a milk sample was obtained the next day. Water intakes were similar (P = 0.947) for both breeds, yet UM sows consumed less feed throughout lactation (P = 0.0002). Average piglet (P < 0.05) and total litter (P < 0.001) weights were greater as of day 7 in UM compared to LW sows. Mean piglet weight on day 24 was 6.13 ± 0.16 kg for UM litters and 5.33 ± 0.33 kg for LW litters. Suckling interval was similar for UM and LW litters on day 5 (P = 0.533), but was shorter for UM litters on day 20 (41.4 ± 1.2 vs. 48.3 ± 2.8 min; P= 0.060). On day 22, daily milk yield corrected for actual suckling interval was greater (10.59 ± 0.47 vs. 8.03 ± 0.65 kg; P = 0.003) in UM sows. Milk from UM sows contained more fat (P= 0.042) and lactose (P = 0.005). In conclusion, the greater growth rate of piglets from UM sows is mainly due to a higher frequency of nursings and to greater energy content of milk. Key words: Sows, lactation, breed, Meishan, behavior, nursing

scholarly journals Effects of month of kidding, parity number, and litter size on milk yield of commercial dairy goats in Australia

2020 ◽  
Vol 103 (1) ◽  
pp. 954-964 ◽  
Author(s):  
F. Zamuner ◽  
K. DiGiacomo ◽  
A.W.N. Cameron ◽  
B.J. Leury
Keyword(s):  
Litter Size ◽  
Milk Yield ◽  
Dairy Goats ◽  
Parity Number

scholarly journals Milk Production of Lacaune Sheep with Different Degrees of Crossing with Manchega Sheep in a Commercial Flock in Spain

Animals ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 520
Author(s):  
Lizbeth E. Robles Jimenez ◽  
Juan C. Angeles Hernandez ◽  
Carlos Palacios ◽  
José A. Abecia ◽  
Anna Naranjo ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Milk Production ◽  
Litter Size ◽  
Milk Yield ◽  
Mixed Model ◽  
The Other ◽  
Commercial Flock ◽  
Parity Number ◽  
Available Information ◽  
Autumn And Winter

The objective of the present study was to evaluate the effect of the grade of crossbreeding (Lacaune x Manchega) and environmental factors on milk production in a commercial flock in Spain. A total of 5769 milk production records of sheep with different degrees of purity of the Lacaune breed crossed with Manchega were used as follows: 100% Lacaune (n = 2960), 7/8 Lacaune (n = 502), 13/16 Lacaune (n = 306), 3/4 (n = 1288), 5/8 Lacaune (n = 441) and 1/2 Lacaune: Manchega (n = 272). Additional available information included the number of parity (1 to 8), litter size (single or multiple), and the season of the year of lambing (spring, summer, autumn and winter). A mixed model was used to evaluate the level of crossbreeding and environmental factors on milk production. The 100% Lacaune sheep presented the highest milk production with respect to the F1 Lacaune x Manchega sheep (p < 0.01), showing that as the degree of gene absorption increases with the Manchega breed, it presents lower milk yield. The 100%, 13/16, and 3/4 Lacaune genotypes had the highest milk yields with respect to the 1/2 Lacaune/Manchega breed (p < 0.001). The Lacaune registered on average 181.1 L in a period adjusted to 160 days of lactation (1.13 L/ day). Likewise, the parity number, litter size, and season of lambing effects showed significant differences (p < 0.01). It was concluded that 13/16 and 3/4 Lacaune/Manchega ewes presented the highest milk yields with respect to the other crosses.

Estrogen Decreases Chemokine Levels in Murine Mammary Tissue: Implications for the Regulatory Role of MIP-1 Alpha and MCP-1/JE in Mammary Tumor Formation

Endocrine ◽  
2003 ◽  
Vol 22 (2) ◽  
pp. 161-168 ◽  
Author(s):  
Peter Fanti ◽  
Michael Nazareth ◽  
Robert Bucelli ◽  
Michael Mineo ◽  
Kathleen Gibbs ◽  
...  
Keyword(s):  
Mammary Tumor ◽  
Tumor Formation ◽  
Regulatory Role ◽  
Mammary Tissue

Gammaglutamyltransferase activity in buffalo mammary tissue during lactation

2006 ◽  
Vol 82 (3) ◽  
pp. 351-354 ◽  
Author(s):  
M. E. Pero ◽  
N. Mirabella ◽  
P. Lombardi ◽  
C. Squillacioti ◽  
A. De Luca ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Epithelial Cells ◽  
Milk Production ◽  
Milk Protein ◽  
Water Buffalo ◽  
Alveolar Epithelial Cells ◽  
Mammary Tissue ◽  
Activity Levels ◽  
Alveolar Epithelial

AbstractIn the present study, the rôle of gammaglutamyltransferase (GGT) during lactation has been investigated in the water buffalo. GGT activity has been evaluated in the mammary tissue at 4 and 6 months after calving and during the non-lactating period. The highest GGT activity levels were found at day 120 (32·57±7·41 U per g) of lactation and were statistically higher than those at 180 (10·76±3·6 U per g) or during the non-lactating period (9·86±7·94 U per g). Histochemistry confirmed these findings and revealed that GGT reactivity was distributed throughout the cytoplasm of alveolar epithelial cells. Such results showed that the GGT production is high during lactation thus supporting the hypothesis that this enzyme plays a rôle in determining milk production in water buffalo by supporting milk protein synthesis.

scholarly journals Covariance components by a repeatability model in Slovenian dairy sheep using test-day records

2009 ◽  
Vol 54 (No. 9) ◽  
pp. 426-434 ◽  
Author(s):  
A. Komprej ◽  
G. Gorjanc ◽  
D. Kon ◽  
M. Kovač
Keyword(s):  
Protein Content ◽  
Litter Size ◽  
Milk Yield ◽  
Genetic Correlations ◽  
Dairy Sheep ◽  
Milk Traits ◽  
Environment Effect ◽  
Covariance Components ◽  
Daily Milk Yield ◽  
Daily Milk

The estimation of covariance components for daily milk yield, fat and protein content was performed in three Slovenian dairy sheep breeds (Bovec, Improved Bovec, and Istrian Pramenka). In the period 1994–2002, 38 983 test-day records of 3 068 ewes were collected according to ICAR regulations (method A4). All the available relationships between animals were considered. For that reason, information on 3 534 animals was included. Test-day records were analysed by a multiple-trait repeatability animal model. In its fixed part, the model contained breed and season of lambing as classes. Days after lambing, parity, and litter size were treated as covariates. Days after lambing were modelled with modified Ali-Schaeffer’s lactation curve, parity with quadratic, and litter size with linear regression. The random part of the model consisted of flock-test month effect, additive genetic effect, permanent environment effect over lactations, and permanent environment effect within lactation. Covariance components were estimated using the restricted maximum likelihood method (REML). The estimated heritabilities were 0.11 for daily milk yield, 0.08 for fat content, and 0.10 for protein content. A relatively high variance ratio for all milk traits was explained by the flock-test month effect (from 0.27 for daily milk yield to 0.57 for protein content), while ratios explained by both permanent environment effects were lower (up to 0.13). Additive genetic correlations between daily milk yield and fat content, and daily milk yield and protein content were negative and similar (–0.36 and –0.37). A high and positive (0.67) additive genetic correlation between fat and protein content was found. Correlations for environmental effects showed a pattern similar to additive genetic correlations. Genetic parameters estimated in Slovenian dairy sheep showed that genetic progress in milk traits could be achieved using test-day milk records.

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