We evaluated the impact of concurrent pregnancy and lactation on: nest-building (i.e., digging, straw-carrying, hair-pulling), food intake, milk output, body weight, and the concentration of estradiol and progesterone in blood. Digging was lower in pregnant-lactating (PL) rabbits, compared with pregnant-only (PO) does, on 21-23 d (52±64 vs. 104±86 g, respectively; mean±SD; P<0.05). Straw-carrying was also reduced in PL does on 24-26 d (9±27 vs. 79±94 g; P<0.005), 27-29 (27±56 vs. 99±77 g; P<0.005), and in the total amount of material introduced into the nest box (132±167 vs. 286±217 g; P<0.02). Hair-pulling was expressed by practically all animals. Food intake declined in PO does on the three days preceding parturition (P<0.01) and increased markedly during lactation; this increase was much larger in PL than in lactating-only (LO) rabbits (P<0.01). Milk output was similar between PL and LO does during the fi rst 21 d of lactation but a marked decline in this parameter occurred in PL does from then until 30 d. The differences in nest-building between PL and PO rabbits may be related to the concentrations of estradiol and progesterone on specifi c days of pregnancy. PL does showed signifi cantly higher estradiol levels than PO animals on pregnancy 1 d (33±13 vs. 23±4 pg/mL; P<0.02) and 21 (34±19 vs. 24±6 pg/mL; P<0.05) and also higher levels of progesterone on pregnancy 1 d (4±5 vs. 1±2 ng/mL; P<0.05). However, PL rabbits had lower levels of progesterone on 7 d (6±3 vs. 9±2 ng/mL; P<0.02) and 14 d (8±3 vs. 11±3 ng/mL; P<0.005) than PO does. Our results indicate that the unique endocrine milieu of PL rabbits has a direct bearing on specifi c behavioral and physiological phenomena that impact productivity on the farm.
Rabbits nurse inside a nest once/day for 3-5 min. We quantified mother's time inside the nest box (TINB) and milk output as we varied the number and age of pups across lactation. TINB was larger and milk output smaller on lactation days 2, 3, 7, or 8, when one pup (2-3 days old) was provided, but normal on Days 4-6, when suckling eight pups. Maintaining 1, 2, or 6-8 growing pups across 30 days increased TINB in the first two groups without modifying milk intake/pup. Substituting a 15 day-old for a newborn increased TINB (Days 15-20) and decreased milk intake/pup (Days 15-30). Substituting for a newborn on Days 5, 9, 13, 17, 21, 25, and 29 increased TINB on such days and revealed a gradual decline in TINB on the "non-switch" days. Litter size, age, and lactation stage interact to determine TINB and milk output.
ABSTRACT:We investigated the capacity of New Zealand White female rabbits to nurse their litter in a nest different from their own (i.e., from another female, in a box containing synthetic or male hair, or in a new box containing part of the original nest material). In females that nursed in their own nest across lactation days 1-3 (one nest-condition) the mere addition of any of the above boxes (without pups) across days 4, 5, 6, 7, or 8 provoked an increase in the latency to enter their own nest for nursing (0.05±0 vs. 2±1 min; P<0.01; Group 1A). In the two-nest condition females took a longer time to enter any box for nursing than they did to enter their own. These differences were significant only for the synthetic nest (4±1.5 min; P<0.05). When the two-nest condition began on lactation day 1 (Group 1B) the latency to enter significantly increased only with the male nest (8±4 vs. 1±0 min, own nest; P<0.05). The time inside the nest box devoted to nursing was practically the same under all conditions and within the normal duration (ca. 3 min). Milk production rose steadily across the days of observation, regardless of the type of nest-box the litter was placed in. We also explored the effect of using alien kits, rather than the female's own, on the rabbit's capacity to nurse them in any of the above nest types (Group 2). The only differences between Group 2 and Group 1B were: a) on day 1 females nursing an alien litter produced less milk (48±5 g) than the two groups nursing their own (69±5, 75±8 g; P<0.02); b) the latency to enter the male nest was smaller in Group 2 (2±2 vs. 8±4 min; P<0.05). These results show that, although able to distinguish among different nest types, rabbits can nurse their own or alien kits in several environments. These findings can be useful in small farm rabbit husbandry practices for facing the problems of kit death or nest deterioration in early lactation.
In this paper, the percentage of the population aged 18 years and over with perception of insecurity during March and April 2021 is estimated for each municipality in Mexico using small area estimation techniques. Two methods are considered: the Empirical Best Linear Unbiased Predictor (EBLUP) and the Spatial Empirical Best Linear Unbiased Predictor (SEBLUP), both based on the Fay-Herriot area-level model. The National Survey of Victimization and Perception of Public Safety 2021 (ENVIPE 2021, for its acronym in Spanish) is the base survey from which the variable object of estimation is obtained; the auxiliary variables that allow to establish the considered models are obtained from other information sources, such as the population and housing census and administrative records. The results are adjusted to satisfy the benchmarking property and are contrasted with direct estimates given by the same survey, ENVIPE 2021, to compare their reliability level.
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